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IBM Informix Spatial Data User's Guide

1. Factory ID Description OGC well known text string 6285 Qatar DATUM D_Qatar SPHEROID International_1924 6378388 297 6286 Qatar 1948 DATUM D_Qatar_1948 SPHEROID Helmert_1906 6378200 298 3 6287 Qornoq DATUM D_Qornoq SPHEROID International_1924 6378388 297 6124 RT 1990 DATUM D_RT_1990 SPHEROID Bessel_1841 6377397 155 299 1528128 6291 South American DATUM D_South_American_1969 Datum 1969 SPHEROID GRS_1967_Truncated 6378160 298 25 6125 Samboja DATUM D_Samboja SPHEROID Bessel_1841 6377397 155 299 1528128 6292 Sapper Hill 1943 DATUM D_Sapper_Hill_1943 SPHEROID International_1924 6378388 297 6293 Schwarzeck DATUM D_Schwarzeck SPHEROID Bessel_Namibia 6377483 865 299 1528128 6294 Segora DATUM D_Segora SPHEROID Bessel_1841 6377397 155 299 1528128 6295 Serindung DATUM D_Serindung SPHEROID Bessel_1841 6377397 155 299 1528128 6308 Stockholm 1938 DATUM D_Stockholm_1938 SPHEROID Bessel_1841 6377397 155 299 1528128 6138 Alaska St George DATUM D_St_George_Island SPHEROID Clarke_1866 6378206 4 Island 294 9786982 6136 Alaska St Lawrence DATUM D_St_Lawrence_Island SPHEROID Clarke_1866 6378206 4 Island 294 9786982 6137 Alaska St Paul DATUM D_St_Paul_Island SPHEROID Clarke_1866 6378206 4 294 9786982 Island 6296 Sudan DATUM D_Sudan SPHEROID Clarke_1880_IGN 6378249 2 293 46602
2. gt gt loadshp 0 Append Mode gt lt Init and Create Mode SQL Mode V Append mode append tablename colname f filename D database 7 gt s server 7 J 7 u username rar a b begin_row e end_row c commit_interval Lae b eaa ic log Lairet Init and create mode create 1 tablename colname f filename gt init gt D database gt gt S server u username pisaid C Cae aa a a b begin_row e end_row in dbspace put sbspace_list gt a n arten si2e sieve ee eene size sgi amenat ic noi dx srid srid log SQL mode Cairat H sq1 1 tablename colname Seg eee a eC in dbspace put sbspace_list gt eee eie Operation modes next next_extent_size log Cineto You use the o flag to set the operation mode for the loadshp command Set the o flag to one of the following options append Spatial features are added to the table specified by the 1 flag The structure of the existing database table must match the structure of a table derived Appendix A Load and unload shapefile data A 3 A 4 from information specified by the 1 command line option and from metadata stored in the shapefile s associated dbf file create Spatial features are l
3. lt Polygon Text gt EMPTY lt LineString Text gt lt LineString Text gt lt M i ltipoint Text gt EMPTY lt Point Text gt lt Point Text gt lt MultiLineString Text gt EMPTY lt LineString Text gt lt LineString Text gt lt MultiPolygon Text gt EMPTY lt Polygon Text gt lt Polygon Text gt Well known text representation in an SQL editor Since the well known text representation is text it can be typed into an SQL script or directly into an SQL editor The text is converted to and from a geometry by a function Functions that convert text to geometry have the following syntax function text description SRID Example ST_PointFromText point zm 10 01 20 04 3 2 9 5 1 The spatial reference identifier SRID the primary key to the spatial_references table identifies the possible spatial reference systems within an IBM Informix instance An SRID is assigned to a spatial column when it is created Before a geometry can be inserted into a spatial column its SRID must match the SRID of the spatial column The text description is made up of three basic components enclosed in single quotation marks geometry type coordinate type coordinate list The geometry type is defined as one of the following point linestring polygon multipoint multilinestring or multipolygon The coordinate type specifies whether the geomet
4. The ST_IsSimple function on page 8 5 Determines whether a geometry is topologically valid The ST_IsValid function on page 8 5 Determines whether an object has Z coordinates Tests whether two geometries meet the conditions specified by a specified DE 91M pattern matrix The SE_Is3D function on page The ST_Relate function oni page 8 9 The ST_Contains function on page 8 2 Determine if a certain Determines whether one geometry completely relationship exists between two contains another geometries Determines whether a geometry crosses another The ST_Crosses function on page 8 2 Determines whether two geometries are completely non intersecting The ST_Disjoint function on page 8 3 FA eal 0 A amp XQ a D a Determines whether the envelopes of two geometries intersect The SE_EnvelopesIntersect unction on page 8 37 ER Determines whether two geometries are spatially equal The ST_Equals function on page 8 3 Determines whether two geometries intersect The ST_Intersects function on page 8 5 Determines whether two geometries overlap The ST_Overlaps function on page 8 8 Determines whether two geometries touch The ST_Touches function on page 8 10 Determines whether one object is completely inside another The ST_Within function on page 8 11
5. The ST_NumGeometries function The ST_NumGeometries function takes a ST_GeomCollection ST_MultiPoint ST_MultiLineString or ST_MultiPolygon and returns the number of geometries in the collection Syntax ST_NumGeometries mpt1 ST MultiPoint ST_NumGeometries mln1 ST _MultiLineString ST_NumGeometries mp11 ST MultiPolygon Return type INTEGER Example The city engineer needs to know the number of distinct buildings associated with each building footprint The building footprints are stored in the buildingfootprints table that was created with the following CREATE TABLE statement CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon The query lists the building_id that uniquely identifies each building and the number of buildings in each footprint with the ST_NumGeometries function SELECT building_id ST_NumGeometries footprint no_of_buildings FROM buildingfootprints building_id no_of_buildings 506 543 1208 178 at pad ey Chapter 8 Spatial functions 8 81 The ST_NuminteriorRing function The ST_NumInteriorRing function takes an ST_Polygon and returns the number of its interior rings Syntax ST_NumInteriorRing pl1 ST Polygon Return type INTEGER Example An ornithologist studying a bird population on several South Sea islands wants to identify which islands contain one or more lakes because the bird species of interest feeds only in freshw
6. This ST_Crosses function matrix applies to ST_LineString and ST_LineString ST_LineString and ST_MultiLineString and ST_MultiLineString and ST_MultiLineString The matrix states that the dimension of the intersection of the interiors must be 0 intersect at a point If the dimension of this intersection was 1 intersect at a linestring the ST_Crosses function would return FALSE but the ST_Overlaps function would return TRUE b Interior Boundary Exterior Interior 0 a Boundary j i i Exterior i Related reference The ST_Crosses function on page 8 26 The ST_Within function The ST_Within function pattern matrix states that the interiors of both geometries must intersect and that the interior and boundary of the primary geometry geometry a must not intersect the exterior of the secondary geometry b 7 20 IBM Informix Spatial Data User s Guide b Interior Boundary Exterior Interior T a Boundary Exterior Related reference The ST_Within function on page 8 110 The ST_Contains function The pattern matrix of the ST_Contains function states that the interiors of both geometries must intersect and that the interior and boundary of the secondary geometry b must not intersect the exterior of the primary geometry a b Interior Boundary Exterior Interior T a a Boundary i i 7 Exterior F F Related reference T
7. Licensees of this program who wish to have information about it for the purpose of enabling i the exchange of information between independently created programs and other programs including this one and ii the mutual use of the information which has been exchanged should contact IBM Corporation J46A G4 555 Bailey Avenue San Jose CA 95141 1003 USA Such information may be available subject to appropriate terms and conditions including in some cases payment of a fee The licensed program described in this document and all licensed material available for it are provided by IBM under terms of the IBM Customer Agreement IBM International Program License Agreement or any equivalent agreement between us Any performance data contained herein was determined in a controlled environment Therefore the results obtained in other operating environments may vary significantly Some measurements may have been made on development level systems and there is no guarantee that these measurements will be the same on generally available systems Furthermore some measurements may have been estimated through extrapolation Actual results may vary Users of this document should verify the applicable data for their specific environment Information concerning non IBM products was obtained from the suppliers of those products their published announcements or other publicly available sources IBM has not tested those products and cannot confirm
8. Properties of geometries are described in Properties of spatial data types on page p i Syntax SE_Is3D g1 ST Geometry Chapter 8 Spatial functions 8 53 Return type BOOLEAN Example The threed_test table is created with INTEGER gid and g1 ST_Geometry columns CREATE TABLE threed_ test gid smallint gl ST_Geometry The following INSERT statements insert two points into the threed_test table The first point does not contain Z coordinates while the second does INSERT INTO threed_test VALUES 1 ST PointFromText point 10 10 1000 l INSERT INTO threed_test VALUES 1 ST_PointFromText point z 10 92 10 12 5 1000 i The query lists the contents of the gid column with the results of the SE_Is3d function The function returns a 0 for the first row which does not have a Z coordinate and a 1 for the second row which does SELECT gid SE_Is3D gl is_it_3d from threed_test gid is_it_3d 1 f 1 t The ST_IsClosed function The ST_IsClosed function takes an ST_LineString or ST_MultiLineString and returns t TRUE if it is closed otherwise it returns f FALSE Properties of geometries are described in Properties of spatial data types on page pi Syntax ST_IsClosed 1n1 ST_LineString ST_IsClosed mln1 ST _MultiLineString Return type BOOLEAN Example The closed_linestring table is created with a single ST_LineString column CREATE TABLE closed_linestring Inl ST_LineString The f
9. The ST_Overlaps function on page 7 4 The ST_Overlaps function on page 7 19 The SE_ParamGet function The SE_ParamGet function with no arguments returns the values of all parameters Calling SE_ParamGet with a parameter name in quotation marks returns the current value of the named parameter Syntax SE_ParamSet name lvarchar returns lvarchar SE_ParamSet returns lvarchar Return type LVARCHAR Example execute function SE ParamGet execute function SE ParamGet MemMode Related reference Optimize spatial queries on page 1 12 The SE_ParamSet function The SE_ParamSet function with no arguments returns usage information Calling SE_ParamSet with a parameter name in quotation marks and a value sets the parameter to the specified value The new value is returned Parameter names are not case sensitive Quotation marks are not required for numeric values Chapter 8 Spatial functions 8 85 Syntax SE_ParamSet name lvarchar value lvarchar returns lvarchar SE_ParamSet returns lvarchar Return type LVARCHAR Example execute function SE ParamSet execute function SE ParamSet memmode 0 execute function SE ParamSet MemMode 1 The ST_Perimeter function The ST_Perimeter function returns the perimeter of a polygon or multipolygon Syntax ST_Perimeter s ST Polygon ST_Perimeter ms ST _MultiPolygon Return type DOUBLE PRECISION Example An ecologis
10. printf Island ID d Total lake perimeter d n island_id total_perimeter SQLFreeStmt lake_cursor SQL_DROP SQLFreeStmt island_cursor SQL_DROP The ST_Intersection function The ST_Intersection function takes two ST_Geometry objects and returns the intersection set as an ST_Geometry object If the two objects do not intersect the return value is an empty geometry Syntax ST_Intersection gl ST Geometry g2 ST Geometry Return type ST_Geometry Example The fire marshal must obtain the areas of the hospitals schools and nursing homes intersected by the radius of a possible hazardous waste contamination The sensitive areas are stored in the sensitive_areas table that is created with the CREATE TABLE statement that follows The zone column defined as an ST_Polygon type stores the outline of each of the sensitive areas CREATE TABLE sensitive_areas id integer name varchar 128 size float type varchar 10 zone ST Polygon Chapter 8 Spatial functions 8 51 The hazardous sites are stored in the hazardous_sites table created with the CREATE TABLE statement that follows The location column defined as an ST_Point type stores a location that is the geographic center of each hazardous site CREATE TABLE hazardous sites site_id integer name varchar 40 location ST Point The ST_Buffer function generates a five mile buffer surrounding the hazardous waste site locations The ST_Interse
11. The SE_Generalize function The ST_GeometryN function The ST_GeometryType function The ST_GeomFromGML function The ST_GeomFromKML function The SE_GeomFromShape function The ST_GeomFromText function The ST_GeomFromWKB function The SE_InRowSize function The ST_InteriorRingN function The ST_Intersection function The ST_Intersects function The SE_Is3D function The ST_IsClosed function The ST_IsEmpty function The SE_IsMeasured function The ST_IsRing function The ST_IsSimple function The ST_IsValid function The ST_Length function The ST_LineFromGML function The ST_LineFromKML function The SE_LineFromShape function The ST_LineFromText function The ST_LineFromWKB function The SE_LocateAlong function The SE_LocateBetween function The SE_M function The SE_Metadatalnit function The SE_Midpoint function 8 9 8 10 8 11 8 12 8 13 8 14 8 15 8 16 8 18 8 19 8 20 8 21 8 22 8 23 8 24 8 26 8 26 8 28 8 29 8 30 8 31 8 32 8 33 8 33 8 35 8 36 8 36 8 36 8 37 8 38 8 39 8 40 8 41 8 42 8 43 8 45 8 46 8 47 8 47 8 48 8 49 8 51 8 52 8 53 8 54 8 55 8 56 8 57 8 58 8 59 8 59 8 60 8 61 8 62 8 63 8 63 8 64 8 65 8 66 8 67 8 68 Contents Vv The ST_MLineFromGML function The ST_MLineFromKML
12. e Between two UNKNOWN coordinate systems that is the srtext column in the spatial_references table for both SRIDs contains UNKNOWN e Between a projected coordinate system and an unprojected coordinate system in which the underlying geographic coordinate systems are the same e Between two projected coordinate systems in which the underlying geographic coordinate systems are the same e Between two coordinate systems with the same geographic coordinate system these are coordinate systems with a difference in false origin or system unit only Appendix B OGC well known text representation of spatial reference systems on page B 1 contains information about supported coordinate systems and their constituent parts Syntax ST_Transform g ST Geometry SRID integer Return type ST_Geometry Examples Example 1 Changing the false origin of a spatial reference system Suppose you created a spatial_references table entry suitable for Australia You can do this with the SE_CreateSrid function as follows EXECUTE FUNCTION SE_CreateSrid 110 45 156 10 Australia lat lon coords expression 1002 Now load all of your data for Australia In this example we just create a table with a few points CREATE TABLE aus_locns name varchar 128 locn ST Point INSERT INTO aus_locns VALUES Adelaide 1002 point 139 14 34 87 INSERT INTO aus_locns VALUES Brisbane 1002 point 153 36 27 86 INSERT INTO
13. lt projection gt lt parameter gt lt linear unit gt lt projection gt PROJECTION lt name gt lt parameter gt PARAMETER lt name gt lt value gt lt value gt lt number gt A coordinate system of a data set is identified by one of the following three keywords PROJCS if the data is in projected coordinates GEOGCS if in geographic coordinates GEOCCS if in geocentric coordinates Copyright IBM Corp 2001 2010 B 1 B 2 The PROJCS keyword is followed by all of the pieces that define the projected coordinate system The first piece of any object is always the name Several objects follow the name the geographic coordinate system the map projection one or more parameters and the linear unit of measure As an example UTM zone 10N on the NAD83 datum is defined as PROJCS NAD_1983_UTM_Zone_10N lt geographic cs gt PROJECTION Transverse Mercator PARAMETER False_Easting 500000 0 PARAMETER False_Northing 0 0 PARAMETER Central_Meridian 123 0 PARAMETER Scale_Factor 0 9996 PARAMETER Latitude_of_Origin 0 0 UNIT Meter 1 0 The name and several objects define the geographic coordinate system object the datum the prime meridian and the angular unit of measure lt geographic cs gt GEOGCS lt name gt lt datum gt lt prime meridian gt lt angular unit gt lt datum gt DATUM lt name gt lt spheroid gt lt spheroid gt SPHEROID lt name gt
14. s Perpendicular point is coincident with the input point on the base of the U SELECT SE _PerpendicularPoint line ST _PointFromText point 5 0 FROM linestring_test expression MULTIPOINT Z 5 0 4 Perpendicular points are located on all three segments of the U SELECT SE PerpendicularPoint line ST _PointFromText point 5 5 FROM linestring_test expression MULTIPOINT Z 0 5 2 5 0 4 10 5 6 Perpendicular points are located at the endpoints of the U SELECT SE_PerpendicularPoint line ST _PointFromText point 5 10 FROM linestring_test expression MULTIPOINT Z 0 10 1 10 10 7 Perpendicular point is on the base of the U SELECT SE PerpendicularPoint line ST _PointFromText point 5 15 FROM linestring_ test expression MULTIPOINT Z 5 0 4 No perpendicular point can be constructed SELECT SE PerpendicularPoint line ST _PointFromText point 15 15 0 FROM linestring_test expression POINT EMPTY The ST_Point function The ST_Point function returns an ST_Point given an X coordinate Y coordinate and spatial reference ID Syntax ST_Point X double precision Y double precision SRID integer Return type ST_Point Chapter 8 Spatial functions 8 87 Example The following CREATE TABLE statement creates the point_test table which has a single point column pt1 CREATE TABLE point_test pt1 ST Point The ST_Point function con
15. type varchar 10 zone ST _Polygon The program fragment populates the sensitive_areas table The question marks represent parameter markers for the ID name size type and zone values that will be retrieved at run time IBM Informix Spatial Data User s Guide Create the SQL insert statement to populate the sensitive_areas table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO sensitive_areas id name size type zone VALUES SE_PolyFromShape d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp id 0 amp pcbvaluel Bind the name to the second parameter pcbvalue2 name_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR 0 0 name 0 amp pcbvalue2 Bind the size to the third parameter pcbvalue3 0 rc SQLBindParameter hstmt 3 SQL PARAM INPUT SQL_C_FLOAT SQL_REAL 0 0 amp size 0 amp pcbvalue3 Bind the type to the fourth parameter pcbvalue4 type_len rc SQLBindParameter hstmt 4 SQL_PARAM_INPUT SQL_C_CHAR SQL_VARCHAR type_len 0 type type_len amp pcbvalue4 Bind the zone geometry to the fifth param
16. 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 JE INSERT INTO empty_test VALUES Polygon ST_PolyFromText polygon empty 1000 JE The query returns the geometry type from the geotype column and the results of the ST_IsEmpty function SELECT geotype ST_IsEmpty g1 Is_it_empty FROM empty_test geotype is_it_empty Point f Point t Linestring f Linestring t Polygon f Polygon je The SE_IsMeasured function 8 56 The SE_IsMeasured function returns t TRUE if the ST_Geometry object has measures otherwise returns f FALSE Properties of geometries are described in Properties of spatial data types on page p i IBM Informix Spatial Data User s Guide Syntax SE_IsMeasured g1 ST Geometry Return type BOOLEAN Example The measure_test table is created with two columns a SMALLINT column gid which uniquely identifies rows and g1 an ST_Geometry column which stores the ST_Point geometries CREATE TABLE measure_test gid smallint gl ST Geometry The following INSERT statements insert two records into the measure_test table The first record stores a point that does not have a measure while the second record does have a measure value INSERT INTO measure_test VALUES 1 ST_PointFromText point 10 10 1000 Ja INSERT INTO measure_test VALUES 2 ST_PointFromText point m 10 92 10 12 5 1000 Ja The query lists the gid column and the results of the SE_IsMeasured fun
17. 6307 Nord Sahara 1959 DATUM D_Nord_Sahara_1959 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6276 NSWC 9Z 2 DATUM D_NSWC_9Z_2 SPHEROID NWL_9D 6378145 298 25 6275 Nouvelle DATUM D_NTF SPHEROID Clarke_1880_IGN 6378249 2 293 46602 Triangulation Francaise 6272 New Zealand DATUM D_New_Zealand_1949 SPHEROID International_1924 6378388 297 Geodetic Datum 1949 6129 Observatario DATUM D_Observatario SPHEROID Clarke_1866 6378206 4 294 9786982 superseded by Tete 6279 OS SN 1980 DATUM D_OS_SN_1980 SPHEROID Airy_1830 6377563 396 299 3249646 6277 OSGB 1936 DATUM D_OSGB_1936 SPHEROID Airy_1830 6377563 396 299 3249646 6278 OSGB 1970 SN DATUM D_OSGB_1970_SN SPHEROID Airy_1830 6377563 396 299 3249646 6280 Padang 1884 DATUM D_Padang_1884 SPHEROID Bessel_1841 6377397 155 299 1528128 6281 Palestine 1923 DATUM D_Palestine_1923 SPHEROID Clarke_1880_Benoit 6378300 79 293 466234571 6282 Pointe Noire DATUM D_Pointe_Noire SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6248 Provisional South DATUM D_Provisional_S_American_1956 American Datum SPHEROID International_1924 6378388 297 1956 6284 Pulkovo 1942 DATUM D_Pulkovo_1942 SPHEROID Krasovsky_1940 6378245 298 3 6200 Pulkovo 1995 DATUM D_Pulkovo_1995 SPHEROID Krasovsky_1940 6378245 298 3 Appendix B OGC well known text representation of spatial reference systems B 11 Table B 5 Horizontal datums continued
18. 7024 Krasovsky 1940 SPHEROID Krasovsky_1940 6378245 298 3 7025 Transit precise ephemeris SPHEROID NWL_9D 6378145 298 25 Appendix B OGC well known text representation of spatial reference systems B 5 Table B 3 Geodetic spheriods continued Factory ID Description OGC well known text string 7032 OSU 1986 geoidal model SPHEROID OSU_86F 6378136 2 298 25722 7033 OSU 1991 geoidal model SPHEROID OSU_91A 6378136 3 298 25722 7027 Plessis 1817 SPHEROID Plessis_1817 6376523 308 64 7035 Authalic sphere SPHEROID Sphere 6371000 0 7028 Struve 1860 SPHEROID Struve_1860 6378298 3 294 73 7029 War Office SPHEROID War_Office 6378300 583 296 7026 NWL 10D WGS 1972 SPHEROID NWL_10D 6378135 298 26 7043 WGS 1972 SPHEROID WGS_1972 6378135 298 26 7030 WGS 1984 SPHEROID WGS_1984 6378137 298 257223563 107001 WGS 1966 SPHEROID WGS_1966 6378145 298 25 107002 Fischer 1960 SPHEROID Fischer_1960 6378166 298 3 107003 Fischer 1968 SPHEROID Fischer_1968 6378150 298 3 107004 Fischer modified SPHEROID Fischer_Modified 6378155 298 3 107005 Hough 1960 SPHEROID Hough_1960 6378270 297 107006 Everest modified 1969 SPHEROID Everest_Modified_1969 6377295 664 300 8017 107007 Walbeck SPHEROID Walbeck 6376896 302 78 107008 Authalic sphere SPHEROID Sphere_ARC_INFO 6370997 0 ARC INFO 107036 GRS 1967 Truncated SPHEROID GRS_1967_Truncated 6378160 298 25
19. IBM Informix Version 11 70 IBM Informix Spatial Data User s Guide tl IBM Informix Version 11 70 IBM Informix Spatial Data User s Guide Note Before using this information and the product it supports read the information in Notices on page I 1 This document contains proprietary information of IBM It is provided under a license agreement and is protected by copyright law The information contained in this publication does not include any product warranties and any statements provided in this publication should not be interpreted as such When you send information to IBM you grant IBM a nonexclusive right to use or distribute the information in any way it believes appropriate without incurring any obligation to you Copyright IBM Corporation 2001 2010 US Government Users Restricted Rights Use duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp Contents Introduction About this publication Types of users Assumptions about your locale What s new in spatial data for IBM Informi V rsi 11 70 Example code conventions Additional documentation Compliance with industry sndards Syntax diagrams How to read a command Jine syntax diagram Keywords and punctuation Identifiers and names How to Provide Documentation Feedback Chapter 1 Getting started with spatial data Comparison of spatial and geodetic data Overview of usin
20. Return type ST_LineString Example An ornithologist studying the bird population on several South Sea islands knows that the feeding zone of the bird species of interest is restricted to the shoreline As part of the calculation of the island s carrying capacity the ornithologist requires the islands perimeters Some of the islands are so large they have several ponds on them However the shorelines of the ponds are inhabited exclusively by another more aggressive bird species Therefore the ornithologist requires the perimeter of the exterior ring only of the islands The ID and name columns of the islands table identifies each island while the land polygon column stores the island s geometry CREATE TABLE islands id integer name varchar 32 land ST Polygon The ST_ExteriorRing function extracts the exterior ring of each island polygon as a linestring The length of the linestring is calculated by the ST_Length function The linestring lengths are summarized by the SUM operator SELECT SUM ST_Length ST_ExteriorRing land FROM islands As shown in the following figure the exterior rings of the islands represent the ecological interface each island shares with the sea Some of the islands have lakes which are represented by the interior rings of the polygons Island shoreline Loo Figure 8 6 Islands and lakes The SE_Generalize function 8 40 The SE_Generalize function reduces the number of vertice
21. SELECT id FROM equal_test WHERE line ST_LineFromText linestring 10 10 20 20 1000 id 1 Syntax ST_Equals gl1 ST Geometry g2 ST Geometry Return type BOOLEAN Example The city GIS technician suspects that some of the data in the buildingfootprints table was somehow duplicated To alleviate concern the technician queries the table to determine if any of the footprints multipolygons are equal The buildingfootprints table is created with the following statement The building_id column uniquely identifies the buildings the lot_id identifies the building s lot and the footprint multipolygon stores the building s geometry CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon The buildingfootprints table is spatially joined to itself by the ST_Equals function which returns 1 whenever it finds two multipolygons that are equal The bf1 building_id lt gt bf2 building_id condition eliminates the comparison of a geometry to itself SELECT bfl building_id bf2 building_id FROM buildingfootprints bf1 buildingfootprints bf2 WHERE ST Equals bf1 footprint bf2 footprint AND bfl building_id lt gt bf2 building_id Related reference The ST_Equals function on page 7 1 The ST_ExteriorRing function The ST_ExteriorRing function returns the exterior ring of a polygon as a linestring Syntax ST_ExteriorRing pl1 ST_Polygon Chapter 8 Spatial functions 8 39
22. function on page 8 85 The value of MemMode takes precedence over the value of the ST MEMMODE environment variable MemMode remains set until the server is shut down When the server is restarted it sets the value to that of ST MEMMODE Use the following functions to view and change the value of the MemMode parameter e SE ParamGet e SE ParamSet Related reference The SE_ParamGet function on page 8 85 The SE_ParamSet function on page 8 85 Spatial data replication You can use spatial data types with Enterprise Replication and high availability clusters The following conditions must be met to replicate spatial data Chapter 1 Getting started with spatial data 1 13 e You must ensure that all copies of the spatial_references table are synchronized at all times e Spatial data type columns in tables that you include in your data replication system must be nullable For information about Enterprise Replication see the IBM Informix Enterprise Replication Guide For information about high availability clusters see the IBM Informix Administrator s Guide The IBM Informix Web Feature Service 1 14 The IBM Informix Web Feature Service WFS is a transaction service that acts as a presentation layer for spatial data WEIS supports the following operations e Creating new feature instances e Deleting feature instances e Updating feature instances e Querying features based on spatial and non
23. ms 8 6 IBM Informix Spatial Data User s Guide Table 8 1 Spatial functions by task type continued Function task type Description Function name Compare geometries and return anew geometry based on how the geometries are related An aggregate function that computes the union of geometries of the same dimension The SE_Dissolve function on page 8 3 Returns the portion of the primary geometry that is not intersected by the secondary geometry The ST_Difference function on page 8 2 Computes the intersection of two geometries The ST_Intersection function on page 8 5 pay Returns the perpendicular projection of a point on the nearest segment of a linestring Returns an ST_Geometry object that is composed of the parts of the two source geometries that are not common to both The SE_PerpendicularPoint unction on page 8 86 The ST_SymDifference unction on page 8 103 ER ER Computes the union of two geometries The ST_Union function on Generate a new geometry from an existing geometry Generates a geometry that is the buffer surrounding the source object The ST_Buffer function on page 8 1 Generates the combined boundary of the geometry The ST_Boundary function on page 8 1 Calculates the spatial extent of all geometries in a table column The SE_BoundingBox function on page 8 1
24. 13 PolyLineZM 15 PolygonZM 18 MultiPointZM 19 PolygonZ 20 MultiPointZ 21 PointM 23 PolyLineM 25 PolygonM 28 MultiPointM Spatial data type Empty ST_Geometry ST_Point ST_MultiLineString ST_MultiPolygon ST_MultiPoint ST_Point with Z coordinates ST_MultiLineString with Z coordinates ST_Point with Z coordinates and measures ST_MultiLineString with Z coordinates and measures ST_MultiPolygon with Z coordinates and measures ST_MultiPoint with Z coordinates and measures ST_MultiPolygon with Z coordinates ST_MultiPoint with Z coordinates ST_Point with measures ST_MultiLineString with measures ST_MultiPolygon with measures ST_MultiPoint with measures Shape types not specified above 2 4 6 and so on are reserved for future use The ST_LineString and ST_Polygon Spatial data types do not have equivalent shape type values Shape types in XY space These topics describe shapes with X and Y coordinates Point A Point consists of a pair of double precision coordinates in the order X Y The following table shows Point byte stream contents Copyright IBM Corp 2001 2010 E 1 Position Field Value Type Number Byte order Byte 0 Shape Type 1 Integer 1 Little endian Byte 4 X X Double 1 Little endian Byte 12 Y Y Double 1 Little endian MultiPoint A MultiPoint consists of a collection of points The bounding box is stored in the order Xmin Ymin Xmax Ymax The following table shows MultiPoint b
25. 5 NOTIFY If there is more than one syntax element with a dotted decimal number the symbol is displayed on a line by itself followed by the syntax elements that are optional For example if you hear the lines 5 5 NOTIFY and 5 UPDATE you know that syntax elements NOTIFY and UPDATE are optional that is you can choose one or none of them The symbol is equivalent to a bypass line in a railroad diagram Specifies a default syntax element A dotted decimal number followed by the symbol and a syntax element indicates that the syntax element is the default option for all syntax elements that share the same dotted decimal number Only one of the syntax elements that share the same dotted decimal number can specify a symbol For example if you hear the lines 2 FILE 2 1 KEEP and 2 1 DELETE you know that KEEP is the default option for the FILE keyword In this example if you include the FILE keyword but do not specify an option default option KEEP is applied A default option also applies to the next higher dotted decimal number In IBM Informix Spatial Data User s Guide this example if the FILE keyword is omitted default FILE KEEP is used However if you hear the lines 2 FILE 2 1 2 1 1 KEEP and 2 1 1 DELETE the default option KEEP only applies to the next higher dotted decimal number 2 1 which does not have an associated keyword and does not apply to 2 FILE Nothing is used if the keyword FILE is omitte
26. 7 14 IBM Informix Spatial Data User s Guide Creating a convex hull is often the first step when tessellating a set of points to create a triangulated irregular network TIN If vertices of the geometry do not form a convex ST_ConvexHull returns a null ST_ConvexHull generates an ST_Polygon value from the convex hull of three of the geometries pictured in the following figure ST_ConvexHull returns a null for the two point ST_LineString because it does not form a convex hull Gay Figure 7 17 The ST_ConvexHull function Related reference The ST_ConvexHull function on page 8 22 The SE_Generalize function The SE_Generalize function reduces the number of vertices in an ST_LineString ST_MultiLineString ST_Polygon or ST_MultiPolygon while preserving the general character of the geometric shape Vt NS Z sZ ST_Polygon ST_MultiLineString Figure 7 18 Geometries resulting from use of SE_Generalize Chapter 7 Determine spatial relationships and transform geometries 7 15 Related reference The SE_Generalize function on page 8 40 The Dimensionally Extended 9 Intersection Model 7 16 The Dimensionally Extended 9 Intersection Model DE 9IM developed by Clementini and others dimensionally extends the 9 Intersection Model of Egenhofer and Herring DE 9IM is a mathematical approach that defines the pair wise spatial relationship between geometries of different types and dimensions T
27. Clarke_1866_Michigan 6378450 047 294 978684677 7034 Clarke 1880 SPHEROID Clarke_1880 6378249 138 293 466307656 7013 Clarke 1880 Arc SPHEROID Clarke_1880_Arc 6378249 145 293 466307656 7010 Clarke 1880 Benoit SPHEROID Clarke_1880_Benoit 6378300 79 293 466234571 7011 Clarke 1880 IGN SPHEROID Clarke_1880_IGN 6378249 2 293 46602 7012 Clarke 1880 RGS SPHEROID Clarke_1880_RGS 6378249 145 293 465 7014 Clarke 1880 SGA SPHEROID Clarke_1880_SGA 6378249 2 293 46598 7042 Everest 1830 definition SPHEROID Everest_1830 6377299 36 300 8017 7018 Everest 1830 modified SPHEROID Everest_1830_Modified 6377304 063 300 8017 7015 Everest adjustment 1937 SPHEROID Everest_Adjustment_1937 6377276 345 300 8017 7044 Everest definition 1962 SPHEROID Everest_Definition_1962 6377301 243 300 8017255 7016 Everest definition 1967 SPHEROID Everest_Definition_1967 6377298 556 300 8017 7045 Everest definition 1975 SPHEROID Everest_Definition_1975 6377299 151 300 8017255 7031 GEM gravity potential SPHEROID GEM_10C 6378137 298 257222101 model 7036 GRS 1967 International SPHEROID GRS_1967 6378160 298 247167427 1967 7019 GRS 1980 SPHEROID GRS_1980 6378137 298 257222101 7020 Helmert 1906 SPHEROID Helmert_1906 6378200 298 3 7021 Indonesian National SPHEROID Indonesian 6378160 298 247 7022 International 1924 SPHEROID International_1924 6378388 297 7023 International 1967 SPHEROID International_1967 6378160 298 25
28. D_Deutsche_Hauptdreiecksnetz SPHEROID Bessel_1841 Hauptdreiecksnetz 6377397 155 299 1528128 6228 Douala DATUM D_Douala SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6230 European Datum DATUM D_European_1950 SPHEROID International_1924 6378388 297 1950 6231 European Datum DATUM D_European_1987 SPHEROID International_1924 6378388 297 1987 6229 Egypt 1907 DATUM D_Egypt_1907 SPHEROID Helmert_1906 6378200 298 3 6258 European Terrestrial DATUM D_ETRF_1989 SPHEROID WGS_1984 6378137 298 257223563 Reference Frame 1989 6232 Fahud DATUM D_Fahud SPHEROID Clarke_1880_RGS 6378249 145 293 465 6132 Final Datum 1958 DATUM D_FD_1958 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6233 Gandajika 1970 DATUM D_Gandajika_1970 SPHEROID International_1924 6378388 297 6234 Garoua DATUM D_Garoua SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6283 Geocentric Datum of DATUM D_GDA_1994 SPHEROID GRS_1980 6378137 298 257222101 Australia 1994 6121 Greek Geodetic DATUM D_GGRS_ 1987 SPHEROID GRS_1980 6378137 298 257222101 Reference System 1987 Appendix B OGC well known text representation of spatial reference systems B 9 Table B 5 Horizontal datums continued Factory ID Description OGC well known text string 6120 Greek DATUM D_Greek SPHEROID Bessel_1841 6377397 155 29
29. E 12 M Array An array of length NumPoints The measures for each part in the PolyLineZM are stored end to end The measures for part 2 follow the measures for part 1 and so on There is no delimiter in the measure array between parts The following table shows PolyLineZM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 13 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer NumParts Little endian Byte X Points Points Point NumPoints Little endian Byte Y Zmin Zmin Double 1 Little endian Byte Y 8 Zmax Zmax Double 1 Little endian Byte Y 16 Z Array Z Array Double NumPoints Little endian Byte Z Mmin Mmin Double 1 Little endian Byte Z 8 Mmax Mmax Double 1 Little endian Byte Z 16 M Array M Array Double NumPoints Little endian Tip X 44 4 NumParts Y X 16 NumPoints Z Y 16 8 NumPoints PolygonZM A PolyLineZM consists of a number of rings A ring is a closed non self intersecting loop A PolyLineZM may contain multiple outer rings The rings of a PolyLineZM are referred to as its parts The following fields are for a PolyLineZM Box The bounding box for the PolyLineZM stored in the order Xmin Ymin Xmax Ymax NumParts The number of rings in the PolyLineZM NumPoints The total number of points for all rings Parts An arra
30. Everest_Adjustment_1937 6377276 345 300 8017 6145 Kalianpur 1962 DATUM D_Kalianpur_1962 SPHEROID Everest_Definition_1962 6377301 243 300 8017255 6146 Kalianpur 1975 DATUM D_Kalianpur_1975 SPHEROID Everest_Definition_1975 6377299 151 300 8017255 6147 Hanoi 1972 DATUM D_Hanoi_1972 SPHEROID Krasovsky_1940 6378245 298 3 6148 Hartebeesthoek 1994 DATUM D_Hartebeesthoek_1994 SPHEROID WGS_1984 6378137 298 257223563 6149 CH 1903 DATUM D_CH1903 SPHEROID Bessel_1841 6377397 155 299 1528128 6150 CH 1903 DATUM D_CH1903 SPHEROID Bessel_1841 6377397 155 299 1528128 6151 Swiss Terrestrial DATUM D_Swiss_TRF_1995 SPHEROID GRS_1980 6378137 298 257222101 Reference Frame 1995 6152 NAD 1983 HARN DATUM D_North_American_1983_HARN SPHEROID GRS_1980 6378137 298 257222101 6153 Rassadiran DATUM D_Rassadiran SPHEROID International_1924 6378388 297 6154 ED 1950 ED77 DATUM D_European_1950_ED77 SPHEROID International_1924 6378388 297 6135 Old Hawaiian DATUM D_Old_Hawaiian SPHEROID Clarke_1866 6378206 4 294 9786982 6601 Antigua Astro 1943 DATUM D_Antigua_1943 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6604 Montserrat Astro DATUM D_Montserrat_1958 SPHEROID Clarke_1880_RGS 1958 6378249 145 293 465 6139 Puerto Rico DATUM D_Puerto_Rico SPHEROID Clarke_1866 6378206 4 294 9786982 Appendix B OGC well known text representation of spatial reference systems B 13 Table B
31. Feedback from all methods is monitored by the team that maintains the user documentation The feedback methods are reserved for reporting errors and omissions in the documentation For immediate help with a technical problem contact IBM Technical Support For instructions see the IBM Informix Technical Support website at http www ibm com planetwide We appreciate your suggestions Introduction XV xvi IBM Informix Spatial Data User s Guide Chapter 1 Getting started with spatial data These topics introduce the IBM Informix spatial extension data types and routines describe how to use the spatial_references table and explain how to create a table with a spatial column and insert data into it IBM Informix spatial data types embed a geographic information system GIS within the IBM Informix database server IBM Informix spatial data types implement the Open GIS Consortium Inc OpenGIS or OGC SQL3 specification of abstract data types ADTs These data types can store spatial data such as the location of a landmark a street or a parcel of land IBM Informix spatial data types also conforms to the OpenGIS Simple Features Specification for SQL Revision 1 1 The GIS of the past were spatially centric and focused on gathering spatial data and attaching non spatial attribute data to it The IBM Informix spatial data types integrate spatial and non spatial data providing a seamless point of access using SQL Structured Quer
32. KML representation of an ST_Geometry spatial type ST_AsKMLJ can also take an optional parameter that describes KML shape attributes Syntax ST_ASKML p ST_Geometry ST_AsKML p ST Geometry attributes lvarchar The attributes parameter can contain one or more KML shape attributes in XML format The following table describes common KML shape attributes Table 8 2 KML shape attributes Attribute Description lt extrude gt A Boolean value that specifies if the geometry is connected to the ground 1 or not 0 To extrude a geometry the value of the lt altitudeMode gt attribute must be either relativeToGround or absolute and the Z coordinate within the lt coordinates gt element must be greater than zero 0 If this attribute is not specified it is false 0 lt tessellate gt A Boolean value that specifies if the geometry should follow the terrain 1 or not 0 To enable tessellation for the geometry the value for the lt altitudeMode gt attribute must be clampToGround If this attribute is not specified it is false 0 Chapter 8 Spatial functions 8 13 Table 8 2 KML shape attributes continued Attribute Description lt altitudeMode gt Specifies how Z coordinates in the lt coordinates gt element are interpreted Possible values are clampToGround default Indicates to ignore the altitude specification in the geometry and place it at ground level relativeToGround Int
33. Returns usage information if called with no parameters The SE_ParamSet function on page 8 8 Returns the version and release date of the IBM Informix Spatial DataBlade Module The SE_Release function on page 8 9 Generates a sort key for geometries The SE_SpatialKey function on page 8 9 Controls tracing to assist in debugging The SE_Trace function on page 8 10 O1 The ST_Area function The ST_Area function returns the area of a polygon or multipolygon Syntax ST_Area pl1 ST Polygon ST_Area mp11 ST_MultiPolygon Return type DOUBLE PRECISION Example The city engineer needs a list of building areas To create the list a GIS technician selects the building ID and area of each building footprint 8 8 IBM Informix Spatial Data User s Guide The building footprints are stored in the buildingfootprints table created with the following CREATE TABLE statement CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon To satisfy the city engineer s request the technician selects the unique key the building_id and the area of each building footprint from the buildingfootprints table SELECT building id ST Area footprint area FROM buildingfootprints building_id area 506 78 00000000000 543 68 00000000000 1208 123 0000000000 178 87 00000000000 The following figure shows the four building footprints lab
34. a Boundary j Exterior T 7 ig This pattern matrix applies to ST_LineString and ST_LineString and to ST_MultiLineString and ST_MultiLineString overlaps In this case the intersection of the geometries must result in a geometry that has a dimension of 1 another ST_LineString or ST_MultiLineString If the dimension of the intersection of the interiors had resulted in 0 a point the ST_Overlaps function would return FALSE however the ST_Crosses function would have returned TRUE Chapter 7 Determine spatial relationships and transform geometries 7 19 b Interior Boundary Exterior Interior 1 T a Boundary j r j Exterior T Related reference The ST_Overlaps function on page 8 83 The ST_Crosses function The ST_Crosses function returns TRUE if the intersection object contains points that are interior to both source geometries but is not equal to either of the source objects This ST_Crosses function pattern matrix applies to ST_MultiPoint and ST_LineString ST_MultiPoint and ST_MultiLineString ST_MultiPoint and ST_Polygon ST_MultiPoint and ST_MultiPolygon ST_LineString and ST_Polygon and ST_LineString and ST_MultiPolygon The matrix states that the interiors must intersect and that at least the interior of the primary geometry a must intersect the exterior of the secondary geometry b b Interior Boundary Exterior Interior T T a Boundary i Exterior
35. areas and five mile hazardous site radii that do not intersect The sensitive_areas table contains several columns that describe the threatened institutions in addition to the zone column which stores the institutions ST_Polygon geometries CREATE TABLE sensitive_areas id integer name varchar 128 size float type varchar 10 zone ST Polygon The hazardous_sites table stores the identity of the sites in the site_id and name columns while the actual geographic location of each site is stored in the location point column CREATE TABLE hazardous sites site_id integer name varchar 40 location ST_Point The ST_Buffer function generates a five mile buffer surrounding the hazardous waste site locations The ST_StartPoint function returns the polygons of the buffered hazardous waste site polygons and the sensitive areas that do not intersect SELECT sa name sensitive_area hs name hazardous_site ST_Area ST_SymDifference ST_buffer hs location 5 5280 sa zone ST_MultiPolygon area FROM hazardous sites hs sensitive_areas sa The following figure shows that the symmetric difference of the hazardous waste sites and the sensitive areas results in the subtraction of the intersected areas Chapter 8 Spatial functions 8 103 AL UUL Figure 8 11 Using the ST_SymDifference function Related reference The ST_SymDifference function on page 7 10 The SE_TotalSize function
36. existing spatial data type functions Syntax SE_AsKML p ST Geometry Return type ST_Geometry Example In this example the SE_AsSKML function converts the location column of the table mytable into its KML description CREATE TABLE mytable id integer location ST Point INSERT INTO mytable VALUES 1 ST_PointFromText point 10 02 20 01 1000 SELECT id SE_AsKML p1 FROM point_t ORDER BY id asc id 100_xy lt Point gt lt coordinates gt 10 02 20 01 lt coordinates gt lt Point gt CREATE TABLE line_t id integer pl ST_LineString INSERT INTO line_t VALUES IBM Informix Spatial Data User s Guide 1 ST_LineFromText linestring 0 0 0 0 0 0 1 0 1 0 0 0 1 0 1 0 1000 1 row s inserted INSERT INTO line_t VALUES 2 ST_LineFromText linestring z 0 0 0 0 0 0 0 1 0 1 1 0 0 0 1 1 0 1 0 1 1000 s 1 row s inserted INSERT INTO line_t VALUES 3 ST_LineFromText linestring m 0 0 0 0 0 0 0 1 0 1 1 0 0 0 1 1 0 1 0 1 1000 1 row s inserted SELECT id SE_AsKML p1 FROM line_t ORDER BY id ASC id 1 lt LineString gt lt coordinates gt 0 0 0 1 1 0 1 1 lt coordinates gt lt LineString gt id 2 lt LineString gt lt coordinates gt 0 0 0 0 1 1 1 0 1 1 1 1 lt coordinates gt lt LineString gt id 3 lt LineString gt lt coordinates gt 0 0 0 1 1 0 1 1 lt coordinates gt lt LineString gt The ST_ASKML function The ST_AsKML function returns the Keyhole Markup Language
37. function 8 85 SE_ParamSet function 8 85 SE_PerpendicularPoint function 8 86 SE_PointFromShape function 3 2 8 89 E 1 SE_PolyFromShape function 3 2 8 94 E 1 SE_Release function 8 98 SE_ShapeToSQL function 8 98 SE_SpatialKey function 8 99 SE_SRID_Authority function 8 101 SE_TotalSize function 8 104 SE_Trace function 8 105 SE_VertexAppend function 8 109 SE_VertexDelete function 8 109 SE_VertexUpdate function 8 109 SE_Xmax function 8 113 SE_Xmin function 8 113 SE_Ymax function 8 114 SE_Ymin function 8 114 SE_Z function 2 4 8 115 Shape representation E 1 Shape types Multipoint E 2 MultiPointM E 5 MultiPointZ E 8 Point E 1 PointM E 5 PointZ E 7 PointZM E 10 Polygon E 3 PolygonM E 6 PolygonZ E 9 PolygonZM_ E 12 Polyline E 2 PolyLineM E 5 PolyLineZ E 8 PolyLineZM_ E 11 values E 1 Shapefiles A 1 A 6 Shapes E 1 dimension 2 3 properties 2 1 Shortcut keys keyboard H 1 shp files A 1 shx files A 1 Simple property 2 5 Size spatial columns 6 1 Smart large objects 6 3 Space requirements 6 1 Spatial columns 1 2 Spatial data 1 1 Spatial data types F 1 Spatial indexes size 6 3 Spatial operator classes 4 4 Spatial reference identifier C 2 C 4 Spatial reference systems B 1 Spatial relationships 7 1 spatial_references table 1 5 replication 1 13 triggers 5 1 SPL 2 9 SRID 2 4 ST_Area function 2 6 2 8 8 8 ST_AsBinary function 1 2 3 2 8 9 ST_AsGML function 3
38. generates a polygon or a multipolygon surrounding a given geometry at a specified radius Buffering a gt gt ST_LineString Buffering a ST_Polygon with one interior ring Buffering a ST_Point Buffering a ST_MultiPoint Figure 7 14 Buffers generated by the ST_Buffer function Related reference The ST_Buffer function on page 8 19 The SE_LocateAlong function For geometries that have measures the location of a particular measure can be found with the SE_LocateAlong function SE_LocateAlong returns the location as an ST_MultiPoint If the source geometry s dimension is 0 for ST_Point and ST_MultiPoint only points with a matching measure value are returned as an ST_MultiPoint However for source geometries whose dimension is greater than 0 the location is interpolated For example if the requested measure value is 5 5 and the ST_LineString vertices have measures of 3 4 5 6 and 7 an interpolated point that falls exactly halfway between the vertices with measure values 5 and 6 is returned SE_LocateAlong locates a point on a linestring by interpolating the given measure value if necessary The following figure shows a case where a point with measure 5 5 is interpolated halfway between the vertices of the ST_LineString with measures 5 and 6 For ST_MultiPoints an exact match is required In the case of the above ST_MultiPoint SE_LocateAlong returns the point that has measure 5 5 Chapter 7 Deter
39. is a 32 bit 4 byte data type that encodes a nonnegative integer in the range 0 4294967295 A double is a 64 bit 8 byte double precision data type that encodes a double precision number using the IEEE 754 double precision format The above definitions are common to both XDR and NDR XDR big endian encoding of numeric types The XDR representation of an unsigned integer is big endian most significant byte first The XDR representation of a double is big endian sign bit is first byte NDR little endian encoding of numeric types The NDR representation of an unsigned integer is little endian least significant byte first The NDR representation of a double is little endian sign bit is last byte Conversion between the NDR and XDR representations of WKB geometry Conversion between the NDR and XDR data types for unsigned integers and doubles is a simple operation involving reversing the order of bytes within each unsigned integer or double in the byte stream Copyright IBM Corp 2001 2010 D 1 Description of WKBGeometry byte streams D 2 The well known binary representation for geometry is described below The basic building block is the byte stream for a point that consists of two doubles The byte streams for other geometries are built using the byte streams for geometries that have already been defined Important These structures are only intended to define the stream of bytes that is
40. lt gml posList dimension 3 gt 110 449999933 45 2559999343 10 109 47999994 46 4600005499 10 109 86000008 43 8400000201 20 lt gml posList gt lt gm LineString gt INSERT INTO gml_linetest VALUES 3 ST_LineFromGML lt gm LineString srsName EPSG 4326 srsDimension 4 gt lt gml posList dimension 4 gt 110 449999933 45 2559999343 10 54 109 47999994 46 4600005499 10 58 109 86000008 43 8400000201 20 64 lt gml posList gt lt gml LineString gt The first record specifies a spatial reference ID of 4 WGS84 and a default dimension of 2 The second and third records contain Z and M measures and pass the spatial reference ID through the srsName attribute Output SELECT FROM gml_linetest gid 1 Inl 4 LINESTRING 110 449999933 45 2559999343 109 47999994 46 4600000469 109 86000008 43 8400000201 gid 2 Inl 4 LINESTRING Z 110 449999933 45 2559999343 10 109 47999994 46 4600005499 10 109 86000008 43 8400000201 20 gid 3 Inl 4 LINESTRING ZM 110 449999933 45 2559999343 10 54 109 47999994 46 4600005499 10 58 109 86000008 43 8400000201 20 64 The ST_LineFromKML function The ST_LineFromKML function takes a KML LineString string and an optional spatial reference ID and returns a linestring object A KML LineString string can contain the KML shape attributes lt extrude gt lt tessellate gt and lt altitudeMode gt but they are ignored in the ST_LineString representation Chapter 8
41. lt semi major axis gt lt inverse flattening gt lt semi major axis gt lt number gt NOTE semi major axis is measured in meters and must be gt 0 lt inverse flattening gt lt number gt lt prime meridian gt PRIMEM lt name gt lt longitude gt lt longitude gt lt number gt The geographic coordinate system string for UTM zone 10N on NAD83 is GEOGCS GCS_North_American_1983 DATUM D_North_American_1983 SPHEROID GRS_ 1980 6378137 298 257222101 PRIMEM Greenwich 0 UNIT Degree 0 0174532925199433 The UNIT object can represent angular or linear units of measure lt angular unit gt lt unit gt lt linear unit gt lt unit gt lt unit gt UNIT lt name gt lt conversion factor gt lt conversion factor gt lt number gt The conversion factor specifies the number of meters for a linear unit or the number of radians for an angular unit per unit and must be greater than zero Therefore the full string representation of UTM zone 10N is PROJCS NAD_1983_UTM Zone_10N GEOGCS GCS_North_American_1983 DATUM D_North_American_1983 SPHEROID GRS_1980 6378137 298 257222101 PRIMEM Greenwich 0 UNIT Degree 0 0174532925199433 PROJECTION Transverse Mercator PARAMETER False Easting 500000 0 PARAMETER False_Northing 0 0 PARAMETER Central_Meridian 123 0 PARAMETER Scale_Factor 0 9996 PARAMETER Latitude of Origin 0 0 UNIT Meter 1 0 I
42. point 10 02 20 01 1000 Ne INSERT INTO y_test VALUES ST_PointFromText point zm 10 02 20 01 5 0 7 0 1000 E The query retrieves the values in the gid column and the DOUBLE PRECISION Y coordinate of the points SELECT gid ST_Y pt1 y_coord FROM y test gid y_coord 1 2 0 01000000000 0 01000000000 NN The SE_Ymax and SE_Ymin functions 8 114 The SE_Ymax and SE_Ymin functions return the maximum and minimum Y coordinates of a geometry Syntax ST_Ymax ST_Geometry ST_Ymin ST_Geometry Return type DOUBLE PRECISION IBM Informix Spatial Data User s Guide The SE_Z function The SE_Z function returns the Z coordinate of a point Syntax SE_Z p1 ST_Point Return type DOUBLE PRECISION Example The z_test table is created with two columns gid which uniquely identifies the row and the pt1 point column CREATE TABLE z_test gid integer pt1 ST Point The following INSERT statements insert two rows One is a point without a Z coordinate or a measure The other has both a Z coordinate and a measure INSERT INTO z_test VALUES l ST_PointFromText point 10 02 20 01 1000 s INSERT INTO z_test VALUES ST_PointFromText point zm 10 02 20 01 5 0 7 0 1000 The query retrieves the values in the gid column and the DOUBLE PRECISION Z coordinate of the points The first row is NULL because the point does not have a Z coordinate SELECT gid SE_Z pt1 z_coo
43. reference ID to return an ST_MultiPolygon Syntax SE_MPolyFromShape s1 lvarchar SRID integer Return type ST_MultiPolygon Example The lots table stores the lot_id which uniquely identifies each lot and the lot multipolygon that contains the lot line geometry CREATE TABLE lots lot_id integer lot ST_MultiPolygon This code fragment populates the lots table Create the SQL insert statement to populate the lots table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO lots lot_id lot VALUES SE MpolyFromShape d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the lot_id to the first parameter pcebvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp lot_id 0 amp pcbvaluel Bind the lot geometry to the second parameter pcbvalue2 lot_shape_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR lot_shape_len 0 lot_shape_buf lot_shape_len amp pcbvalue2 Execute the insert statement rc SQLExecute hstmt The ST_MPolyFromText function The ST_MPolyFromText function takes a well known text representation of type ST_MultiPolygon and a spatial reference ID and returns an ST_MultiPolygon 8 78 IBM Informix Spatial Dat
44. site_id integer name varchar 40 location ST_Point The program fragment populates the hazardous_sites table Create the SQL insert statement to populate the hazardous_sites table The question marks are parameter markers that indicate x the column values that will be inserted at run time sprintf sql_stmt INSERT INTO hazardous_sites site_id name location VALUES SE_PointFromShape d srid Prepare the SQL statement for execution Chapter 8 Spatial functions 8 89 rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the site_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL PARAM INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp site_id 0 amp pcbvaluel Bind the name to the second parameter pcbvalue2 name_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR 0 0 name 0 amp pcbvalue2 Bind the location geometry to the third parameter pcbvalue3 location_shape_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR location_shape_len 0 location_shape_buf location_shape_len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The ST_PointFromText function The ST_PointFromText function takes a well known text representation of type point and a spatial reference ID and returns a point Syntax ST_PointFromText WKT
45. updated after the shapefile data has been loaded Unless this option is specified when executing loadshp o create or loadshp o init a unique B tree index is built on the se_row_id column an R tree index is built on the geometry column and statistics are updated for the table after the shapefile data has been loaded p optional The IBM Informix password If you specify the p option you must also specify the u option put optional Specifies the sbspaces in which large shapes inserted into the load table s geometry column will be stored Multiple sbspace names must be separated by commas and no white space must appear in the list of sbspace names This option is not valid with the append option of the o flag s optional The IBM Informix server Defaults to the value of the INFORMIXSERVER environment variable srid optional The spatial reference ID for the data you are loading The integer you specify must exist as a spatial reference ID in the spatial_references table If you do not specify the srid command line option the spatial reference ID defaults to 0 u optional The IBM Informix user name If you specify the u option you must also specify the p option V Prints version information for this utility Appendix A Load and unload shapefile data A 5 The unloadshp utility The unloadshp utility copies spatial features and associated attributes from a table in an IBM Informix database into an E
46. 20 20 Multipoint with two points ST_MultiPoint multipoint z 10 10 2 20 20 3 Multipoint with Z coordinates ST_MultiPoint multipoint m 10 10 4 20 20 5 Multipoint with measures ST_MultiPoint multipoint zm 10 10 2 4 20 20 3 5 Multipoint with Z coordinates and measures Empty multilinestring Empty multilinestring with Z coordinates Empty multilinestring with measures Empty multilinestring with Z coordinates and measures ST_MultiLineString ST_MultiLineString multilinestring empty multilinestring z empty ST_MultiLineString multilinestring m empty ST_MultiLineString multilinestring zm empty Appendix C OGC well known text representation of geometry C 3 Geometry type ST_MultiLineString ST_MultiLineString ST_MultiLineString ST_MultiLineString ST_MultiPolygon ST_MultiPolygon ST_MultiPolygon ST_MultiPolygon ST_MultiPolygon ST_MultiPolygon ST_MultiPolygon ST_MultiPolygon Text description Comment multilinestring 10 05 10 28 20 95 20 89 20 95 Multilinestring 20 89 31 92 21 45 multilinestring z 10 05 10 28 3 4 20 95 20 89 4 5 Multilinestring with Z coordinates 20 95 20 89 4 5 31 92 21 45 3 6 multilinestring m 10 05 10 28 8 4 20 95 20 89 Multilinestring with measures 9 5 20 95 20 89 9 5 31 92 21 45 8 6 multilinestring zm 10 05 10 28 3 4 8 4 20 95 20 89 Multilinestring with Z coordinates 4 5 9 5 20 95 20 89 4 5 9 5
47. 3 8 11 ST_AsKML function 3 4 ST_AsShape function 1 2 ST_AsText function 1 2 3 1 ST_Boundary function 8 16 ST_Buffer function 7 12 8 19 ST_Centroid function 2 6 2 8 8 20 ST_Contains function 8 21 ST_ConvexHull function 7 15 8 22 ST_CoordDim function 8 23 ST_Crosses function 7 5 8 26 ST_Difference function 7 8 8 28 ST_Dimension function 8 29 ST_Disjoint function 7 2 8 30 ST_Distance function 8 32 ST_EndPoint function 2 5 8 33 ST_Envelope function 2 3 8 34 ST_EnvelopeAsGML function 3 3 8 35 ST_EnvelopeAsKML function 3 4 ST_EnvelopeFromGML function 8 36 ST_Equals function 7 1 8 38 ST_ExteriorRing function 2 6 8 39 ST_Geometry_Ops operator class 4 4 ST_GeometryN function 2 1 8 41 ST_GeometryType function 2 1 8 42 ST_GeomFromGML function 3 3 8 43 ST_GeomFromKML function 3 4 8 45 ST_GeomFromText function 3 1 8 47 ST_GeomFromWKB function 3 2 8 48 ST_InteriorRingN function 2 6 8 49 ST_Intersection function 7 7 8 51 ST_Intersects function 7 2 8 53 ST_IsClosed function 2 5 2 7 8 54 ST_IsEmpty function 2 3 8 55 ST_IsRing function 2 5 8 57 ST_IsSimple function 2 2 8 58 ST_Length function 2 5 2 7 8 59 ST_LineFromGML function 3 3 8 60 ST_LineFromKML function 3 4 8 61 ST_LineFromText function 3 1 8 63 ST_LineFromWKB function 3 2 8 63 ST_LineString type 2 5 ST_MLineFromGML function 3 3 8 68 ST_MLineFromKML function 3 4 8 69 ST_ML
48. 3047972650 9014 Fathom UNIT Fathom 1 8288 9030 International nautical mile UNIT Nautical_Mile 1852 9031 German legal meter UNIT Meter_German 1 000001359650 9033 US survey chain UNIT Chain_US 20 11684023368047 9034 US survey link UNIT Link_US 0 2011684023368047 9035 US survey mile UNIT Mile_US 1609 347218694438 9036 Kilometer UNIT Kilometer 1000 9037 Yard Clarke UNIT Yard_Clarke 0 914391795 9038 Chain Clarke UNIT Chain_Clarke 20 11661949 9039 Link Clarke s ratio UNIT Link_Clarke 0 2011661949 9040 Yard Sears UNIT Yard_Sears 0 9143984146160287 9041 Sear s foot UNIT Foot_Sears 0 3047994715386762 9042 Chain Sears UNIT Chain_Sears 20 11676512155263 9043 Link Sears UNIT Link_Sears 0 2011676512155263 9050 Yard Benoit 1895 A UNIT Yard_Benoit_1895_A 0 9143992 9051 Foot Benoit 1895 A UNIT Foot_Benoit_1895_A 0 3047997333333333 Appendix B OGC well known text representation of spatial reference systems B 3 Table B 1 Linear units of measure continued Factory ID Description OGC well known text string 9052 Chain Benoit 1895 A UNIT Chain_Benoit_1895_A 20 1167824 9053 Link Benoit 1895 A UNIT Link_Benoit_1895_A 0 201167824 9060 Yard Benoit 1895 B UNIT Yard_Benoit_1895_B 0 9143992042898124 9061 Foot Benoit 1895 B UNIT Foot_Benoit_1895_B 0 3047997347632708 9062 Chain Benoit 1895 B UNIT Chain_Benoit_1895_B 20 116782494
49. 31 92 21 45 3 6 8 6 and measures multipolygon empty Empty multipolygon multipolygon z empty Empty multipolygon with Z coordinates multipolygon m empty Empty multipolygon with measures multipolygon zm empty Empty multipolygon with Z coordinates and measures multipolygon 10 10 10 20 20 20 2015 1010 Multipolygon 50 40 50 50 60 50 60 40 50 40 multipolygon z 10 10 7 10 20 8 20 20 7 20 155 Multipolygon with Z coordinates 10 10 7 50 40 6 50 50 6 60 50 5 60 40 6 50 40 7 multipolygon m 10 10 2 10 20 3 20 20 4 2015 Multipolygon with measures 5 10 10 2 50 40 7 50 50 3 60 50 4 60 40 5 50 40 7 multipolygon zm 10 10 7 2 10 20 8 3 202074 Multipolygon with Z coordinates 20 15 5 5 10 10 7 2 50 40 6 7 50 50 6 3 60 50 5 4 and measures 60 40 6 5 50 40 7 7 Modified well known text representation The IBM Informix software provides an additional modified well known text representation for loading text strings directly into geometry columns without filtering the string through one of the Spatial DataBlade text functions By placing the SRID in front of the text description you can insert the resulting text string directly into a spatial column The load statement in the DB Access utility reads text files generated with this format and inserts the modified well known text representation into the geometry columns To create a modified well kn
50. 33 08 93 37 33 19 IBM Informix Spatial Data User s Guide 94 36 32 49 lt gml posList gt lt gml LinearRing gt lt gml exterior gt lt gml Pol ygon gt lt gml Pol ygonMember gt lt gml PolygonMember gt lt gm1 Polygon srsName EPSG 4326 srsDimension 2 gt lt gml exterior gt lt gm LinearRing gt lt gml posList dimension 2 gt 84 36 32 49 82 66 32 69 82 15 32 46 83 09 33 08 83 37 33 19 84 36 32 49 lt gml posList gt lt gml LinearRing gt lt gml exterior gt lt gml Polygon gt lt gml1 PolygonMember gt lt gml MultiPolygon gt 4 This record specifies a spatial reference ID of 4 WGS84 and both member polygons have a dimension of 2 and six sides Output SELECT FROM test_multipoly id 1 geom 4 MULTIPOLYGON 94 3600000805 32 4900000536 92 6599999799 326899999866 92 1500000335 32 4600000469 93 0900000201 33 0800000738 93 3700000268 33 1899999866 94 3600000805 32 4900000536 84 3600000805 32 4900000536 82 6599999799 326899999866 82 1500000335 32 4600000469 83 0900000201 33 0800000738 83 3700000268 33 1899999866 84 3600000805 32 4900000536 The ST_MPolyFromKML function The ST_MPolyFromKML function takes a MultiGeometry and Polygon combination and an optional spatial reference ID and returns a polygon object Syntax ST_MPolyFromKML kmlstring lvarchar ST_MPolyFromKML kmlstring lvarchar SRID integer Return type ST_MultiPolygon Example The t
51. 82 1500000335 32 4600000469 83 0900000201 33 0800000738 83 3700000268 33 1899999866 84 3600000805 32 4900000536 Chapter 8 Spatial functions 8 93 The ST_PolyFromKML function The ST_PolyFromKMLJ function takes a KML Polygon string representation and an optional spatial reference ID and returns a polygon object Syntax ST_PolyFromKML kmlstring lvarchar ST_PolyFromKML kmlstring lvarchar SRID integer Return type ST_Polygon Example EXECUTE FUNCTION ST_PolyFromKML lt Polygon gt lt outerBoundaryIs gt lt LinearRing gt lt coordinates gt 122 365662 37 826988 0 122 365202 37 826302 0 122 364581 37 82655 0 122 365038 37 827237 0 122 365662 37 826988 0 lt coordinates gt lt LinearRing gt lt outerBoundaryIs gt lt Polygon gt 4 Output 4 POLYGON Z 122 365662056 37 8269879529 0 122 365202058 37 8263019779 0 122 364580958 37 8265500822 0 122 36503794 37 827237063 0 122 365662056 37 8269879529 0 The SE_PolyFromShape function 8 94 The SE_PolyFromShape function returns an ST_Polygon from a shape of type polygon and a spatial reference ID Syntax SE_PolyFromShape sl lvarchar SRID integer Return type ST_Polygon Example The sensitive_areas table contains several columns that describe the threatened institutions in addition to the zone column which stores the institution polygon geometries CREATE TABLE sensitive_areas id integer name varchar 128 size float
52. D 4 POSC EPSG B 1 PROJCS keyword B 1 Projections B 1 R R tree access method about 4 1 operators for 4 4 R tree indexes 8 80 Replication of spatial data 1 13 Rings 2 5 D 4 rowsize column 6 2 S SBSPACENAME configuration parameter 1 3 sbspaces for spatial data 1 4 Screen reader reading syntax diagrams H 1 SE_AsGML function 3 3 8 11 SE_AsKML function 3 4 8 12 SE_AsShape function 3 2 8 14 E 1 SE_AsText function 8 15 SE_BoundingBox function 8 18 SE_CreateSRID function 8 24 SE_CreateSrtext function 8 26 SE_Dissolve function 8 31 SE_EnvelopeAsKML function 8 36 SE_EnvelopeFromKML function 3 4 8 37 SE_EnvelopesIntersect function 8 37 SE_Generalize function 7 15 8 40 SE_GeomFromShape function 3 2 8 46 E 1 SE_InRowSize function 8 48 SE_Is3D function 2 4 8 53 SE_IsMeasured function 2 4 8 56 SE_LineFromShape function 3 2 8 62 SE_LocateAlong function 7 13 8 64 SE_LocateBetween function 7 14 8 65 SE_M function 2 4 8 66 X 2 IBM Informix Spatial Data User s Guide SE_Metadata opaque type 5 1 SE_MetaDatalInit function 8 67 SE_MetadataTable table 5 1 SE_Midpoint function 8 68 SE_MlineFromShape function 8 70 SE_MLineFromShape function 3 2 SE_Mmax function 8 72 SE_Mmin function 8 72 SE_MPointFromShape function 3 2 8 74 SE_MPolyFromShape function 3 2 8 78 SE_Nearest function 8 80 SE_NearestBbox function 8 80 SE_OutOfRowSize function 8 83 SE_ParamGet
53. Ellipsoids B 5 EMPTY keyword C 2 Endpoints 2 5 ESRI binary shape representation E 1 ESRI shape representation 3 2 Extended Backus Naur Form B 1 Exterior rings 7 12 Copyright IBM Corp 2001 2010 F False origin 1 7 Falsem 1 5 Falsex 1 5 Falsey 1 5 Falsez 1 5 Fragmented tables 5 1 G GEOGCS keyword B 1 Geographic Information Systems 1 1 Geography markup language GML 3 3 Geography Markup Language GML 8 11 Geometry dimension 2 3 properties 2 1 Geometry type C 2 geometry_columns table 1 9 A 2 F 1 geometry_type column 1 9 F 1 GIS 1 1 GML representation 3 3 H Homogeneous collections 2 1 Indexes access methods for 4 1 operator classes for 4 4 R tree using 4 1 syntax for 4 1 using 4 5 industry standards xi infoshp utility A 1 Instantiated data type 2 1 Interior rings 7 12 K Keyhole markup language KML 3 4 KML representation 3 4 L Linestrings 2 1 2 5 C 2 closed 2 5 Little endian D 1 Loading data A 1 loadshp utility A 1 A 2 Locale override 2 9 M MapObjects 1 2 Measures 2 4 3 2 7 13 7 14 Modified well known text representation C 4 Multilinestrings 2 1 C 2 Multipoints 2 1 C 2 Multipolygons 2 1 C 2 D 4 N NDR D 1 converting to XDR D 1 Nearest neighbor queries 8 80 O ODBC 1 2 D 1 Open GIS Consortium 1 1 OpenGIS Consortium 2 1 Operator classes 4 4 Origin false 1 7 P Parallel database query PDQ feature 5 1 Points 2 1 C 2 Polygons 2 1 C 2
54. Flat_Polar_Quartic B 18 IBM Informix Spatial Data User s Guide Table B 8 Map projections continued Factory ID Description OGC well known text string 43046 Craster Parabolic PROJECTION Craster_Parabolic 43047 Gnomonic PROJECTION Gnomonic 43048 Bartholomew Times PROJECTION Times 43049 Vertical Near Side Perspective PROJECTION Vertical_Near_Side_Perspective Appendix B OGC well known text representation of spatial reference systems B 19 B 20 IBM Informix Spatial Data User s Guide Appendix C OGC well known text representation of geometry Each geometry type has a well known text representation from which new instances can be constructed or existing instances can be converted to textual form for alphanumeric display Related reference Well known text representation on page 3 1 Well known binary representation on page 3 1 Well known text representation in a C program The well known text representation of geometry can be incorporated into a C program The structure for such an implementation is defined below The notation denotes zero or more repetitions of the tokens within the braces The braces do not appear in the output token list lt Geometry Tagged Text gt lt Point Tagged Text gt lt LineString Tagged Text gt lt Polygon Tagged Text gt lt MultiPoint Tagged Text gt lt MultiLineString Tagged Text gt lt MultiPolygon Tagged Text gt lt Po
55. Kong 1980 DATUM D_Hong_Kong_1980 SPHEROID International_1924 6378388 297 106262 Datum Lisboa Bessel DATUM D_Datum_Lisboa_Bessel SPHEROID Bessel_1841 6377397 155 299 1528128 106263 Datum Lisboa DATUM D_Datum_Lisboa_Hayford SPHEROID International_1924 Hayford 6378388 297 Appendix B OGC well known text representation of spatial reference systems B 15 Table B 5 Horizontal datums continued Factory ID Description OGC well known text string 106264 Reseau Geodesique DATUM D_RGF_1993 SPHEROID GRS_1980 6378137 298 257222101 Francais 1993 106265 New Zealand Geodetic Datum 2000 DATUM D_NZGD_2000 SPHEROID GRS_1980 6378137 298 257222101 Prime meridians IBM Informix spatial data types support many prime meridians The following table lists a representative sample of the prime meridians supported by the IBM Informix spatial data types For a complete list of supported prime meridians see the file INFORMIXDIR extend spatial version include pedef h Table B 6 Prime meridians Factory ID Description OGC well known text string 8901 Greenwich 0 00 00 PRIMEM Greenwich 0 8912 Athens 23 42 58 815 E PRIMEM Athens 23 7163375 8907 Bern 7 26 22 5 E PRIMEM Bern 7 439583333333333 8904 Bogota 74 04 51 3 W PRIMEM Bogota 74 08091666666667 8910 Brussels 4 22 04 71 E PRIMEM Brussels 4 367975 8909 Ferro 17 40 00 W P
56. SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the lot_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL PARAM INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp lot_id 0 amp pcbvaluel Chapter 8 Spatial functions 8 79 Bind the lot geometry to the second parameter pcbvalue2 lot_wkb_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C BINARY SQL_INFX_UDT_LVARCHAR lot_wkb_len 0 lot_wkb_buf lot_wkb_len amp pcbvalue2 Execute the insert statement rc SQLExecute hstmt The SE_Nearest and SE_NearestBbox functions 8 80 The SE_Nearest function allows you to query for the nearest neighbors to a specified geometry The SE_Nearest function uses an R tree index which you must create if it does not already exist Query results are returned in order of increasing distance from the query object The distance is measured using the same algorithm as used by the ST_Distance function The SE_NearestBBox function is similar to SE_Nearest but distances are measured between objects bounding boxes envelopes Because this is a simpler calculation SE_NearestBBox executes more quickly but may return objects in a different order depending on the actual shape of the objects These functions can only be used in the WHERE clause of a query Important To use the SE_Nearest and SE_NearestBBox functions yo
57. ST_Distance function on page 8 3 Returns the data type The ST_GeometryType unction on page 8 42 p Returns the number of points The ST_NumPoints function on page 8 8 Returns the spatial reference ID The ST_SRID function on page 0o 100 Returns the maximum and minimum X coordinate The SE_Xmax and SE_Xmin unctions on page 8 113 p Returns the maximum and minimum Y coordinate The SE_Ymax and SE_Ymin unctions on page 8 11 iS Returns the maximum and minimum Z coordinate The ST_Zmax and ST_Zmin ER unctions on page 8 115 Returns the maximum and minimum measure value The SE_Mmax and SE Mmini p unctions on page 8 72 ca Chapter 8 Spatial functions 8 5 Table 8 1 Spatial functions by task type continued Function task type Description Function name Determine the properties of a Determines whether a linestring or geometry multilinestring is closed The ST_IsClosed function on page 8 5 Determines whether a geometry is empty it has no points The ST_IsEmpty function on page 8 5 Determines whether a geometry has measures Determines whether a linestring is a ring it is closed and simple The SE_IsMeasured function on page 8 5 The ST_IsRing function on page 8 5 Determines whether a geometry is simple
58. The SE_TotalSize function returns the sum of the in row and out of row components of a geometry You can use this function to obtain an estimate of the amount of disk space consumed by one or more geometries However this function does not account for dbspace and sbspace overhead so cannot be used to obtain an exact total Syntax SE_TotalSize ST_Geometry Return type INTEGER See also The SE_InRowSize function on page 8 48 The SE_OutOfRowSize function on page 8 83 The ST_Touches function 8 104 The ST_Touches function returns t TRUE if none of the points common to both geometries intersect the interiors of both geometries otherwise it returns f FALSE At least one geometry must be an ST_LineString ST_Polygon ST_MultiLineString or ST_MultiPolygon Syntax ST_Touches gl ST_Geometry g2 ST_Geometry Return type BOOLEAN IBM Informix Spatial Data User s Guide Example The GIS technician has been asked to provide a list of all sewer lines whose endpoints intersect another sewer line The sewerlines table is created with three columns The first column sewer_id uniquely identifies each sewer line The INTEGER class column identifies the type of sewer line generally associated with the line s capacity The sewer ST_LineString column stores the sewer line s geometry CREATE TABLE sewerlines sewer_id integer class integer sewer ST_LineString The query returns a list of sewer_i
59. WKBPolygon byte byteOrder uint32 wkbType Hi 3 uint32 numRings LinearRing rings numRings WKBMul1 tiPoint byte byteOrder uint32 wkbType 4 uint32 num_wkbPoints WKBPoint WKBPoints num_wkbPoints WKBMultiLineString byte byteOrder uint32 wkbType 5 uint32 num_wkbLineStrings WKBLineString WKBLineStrings num_wkbLineStrings wkbMultiPolygon byte byteOrder uint32 wkbType 6 uint32 num_wkbPolygons WKBPolygon wkbPolygons num_wkbPolygons WKBGeometry union WKBPoint point WKBLineString linestring WKBPolygon polygon WKBGeometryCollection collection WKBMu1 ti Point mpoint WKBMultiLineString mlinestring WKBMu1tiPolygon mpolygon I WKBGeometryCollection byte byte_order uint32 wkbType 7 uint32 num_wkbGeometries WKBGeometry wkbGeometries num_wkbGeometries Appendix D OGC well known binary representation of geometry D 3 WKB Polygon Figure D 1 Well known binary representation for a geometry object in NDR format B 1 of type polygon T 3 with two rings NR 2 and each ring having three points NP 3 The number of bytes in each box is shown 8 8 8 8 8 8 4 8 8 8 8 8 8 Assertions for well known binary representation for geometry D 4 The well known binary representation for geometry is designed to represent instances of the geometry types described in the geometry object model and in the O
60. a spatial column must use the same spatial reference system Geometry is the term adopted by the OpenGIS Consortium to refer to two dimensional spatial data The IBM Informix spatial functions use the parameters of a spatial reference system to translate and scale each floating point coordinate of the geometry into 54 bit positive integers prior to storage When retrieved the coordinates are restored to their external floating point format Related concepts Overview of using spatial data on page 1 2 Spatial reference system on page 2 4 Related reference The SE_CreateSRID function on page 8 24 Establish a spatial reference system on page 1 8 The structure of the spatial_references table Before you can create geometry and insert it into a table you must enter the SRID of that geometry into the spatial_references table The columns of the spatial_references table are described in the following table Table 1 1 The spatial_references table Column name Type Example value Description srid INTEGER NOT NULL 12345 Primary key the unique key for the record describing a particular spatial reference system description VARCHAR 64 WGS 1984 A text description of the spatial reference system auth_name VARCHAR 255 EPSG The name of the standard or standards body cited for the reference system auth_srid INTEGER 4326 The ID of the spatial reference system as defined by the authority
61. and query the rowsize column of the systables table In this example a table called lots is created with three columns create table lots lot_id integer owner_name varchar 128 owner_address varchar 128 Selecting the row size for the lots table from systables returns a value of 262 bytes select rowsize from systables where tabname lots 262 Tables containing variable length columns of type VARCHAR or NVARCHAR require the row size to be reduced to reflect the actual length of the data stored In this example the owner_name and owner_address columns are variable length VARCHAR columns and can occupy up to 129 bytes each 128 bytes for data plus an extra byte for the null terminator The average size of the owner name is actually 68 bytes and the average size of the address is 102 bytes Therefore the estimated row size should be reduced to 174 bytes Estimate dbspace overhead requirements The amount of dbspace overhead that spatial tables require depends on the number of rows Spatial tables with more than 10 000 rows require about 200 bytes of overhead per row 6 2 IBM Informix Spatial Data User s Guide Spatial tables with fewer than 10 000 rows but more than 1 000 rows require 300 bytes per row Spatial tables with fewer than 1 000 rows require 400 bytes per row Estimating the smart large object storage space A spatial data value is stored in row if the value is less than or equal to 930 bytes However if th
62. by the IBM Informix spatial data types For a complete list of supported map projections see the file INFORMIXDIR extend spatial version include pedef h Table B 8 Map projections Factory ID Description OGC well known text string 43001 Plate Carree PROJECTION Plate_Carree 43002 Equidistant Cylindrical PROJECTION Equidistant_Cylindrical 43003 Miller Cylindrical PROJECTION Miller_Cylindrical 43004 Mercator PROJECTION Mercator 43005 Gauss Kruger PROJECTION Gauss_Kruger 43006 Transverse Mercator PROJECTION Transverse_Mercator 43007 Albers PROJECTION Albers 43008 Sinusoidal PROJECTION Sinusoidal Appendix B OGC well known text representation of spatial reference systems B 17 Table B 8 Map projections continued Factory ID Description OGC well known text string 43009 Mollweide PROJECTION Mollweide 43010 Eckert VI PROJECTION Eckert_VI 43011 Eckert V PROJECTION Eckert_V 43012 Eckert IV PROJECTION Eckert_IV 43013 Eckert III PROJECTION Eckert_III 43014 Eckert II PROJECTION Eckert_II 43015 Eckert I PROJECTION Eckert_I 43016 Gall Stereographic PROJECTION Gall_Stereographic 43017 Behrmann PROJECTION Behrmann 43018 Winkel I PROJECTION Winkel_I 43019 Winkel II PROJECTION Winkel_II 43020 Lambert Conformal Conic PROJECTION Lamber
63. case sensitive because they illustrate utility syntax Other types of syntax such as SQL are not case sensitive The Creating a No Conversion Job diagram illustrates the following steps 1 Type onpladm create job and then the name of the job 2 Optionally type p and then the name of the project 3 Type the following required elements e n e d and the name of the device e D and the name of the database e t and the name of the table Introduction Xiii 4 Optionally you can choose one or more of the following elements and repeat them an arbitrary number of times e S and the server name e T and the target server name e The run mode To set the run mode follow the Setting the Run Mode segment diagram to type f optionally type d p or a and then optionally type l or u 5 Follow the diagram to the terminator Keywords and punctuation Keywords are words reserved for statements and all commands except system level commands When a keyword appears in a syntax diagram it is shown in uppercase letters When you use a keyword in a command you can write it in uppercase or lowercase letters but you must spell the keyword exactly as it appears in the syntax diagram You must also use any punctuation in your statements and commands exactly as shown in the syntax diagrams Identifiers and names Variables serve as placeholders for identifiers and names in the syntax diagrams and examples You c
64. cited in auth_name Chapter 1 Getting started with spatial data 1 5 Table 1 1 The spatial_references table continued Column name Example value Description falsex falsey FLOAT NOT NULL 180 The external floating point X coordinates are converted to integers for storage in the database by subtracting the falsex values FLOAT NOT NULL 90 The external floating point Y coordinates are converted to integers for storage in the database by subtracting the falsey values xyunits FLOAT NOT NULL 1000000 Before being inserted into the database the external floating point X and Y coordinates are scaled by the value in xyunits adding a half unit and truncating the remainder falsez FLOAT NOT NULL 1000 The external floating point Z coordinates are converted to integers for storage in the database by subtracting the falsez values zunits FLOAT NOT NULL 1000 A factor used to scale the Z coordinate falsem FLOAT NOT NULL 1000 The external floating point M coordinates are converted to integers for storage in the database by subtracting the falsem values munits FLOAT NOT NULL 1000 A factor used to scale the measure values srtext CHAR 2048 The srtext column contains the WKT GEOGCS GCS_WGS_1984 representation of the spatial reference DATUM D_WGS 1984 system SPHEROID WGS_1984 6378137 298 257223563 contains a PRIMEM Greenwich 0 complete description o
65. coordinates that represents the display polygon The SE_PolygonFromShape function converts the display window shape into a polygon that the SE_EnvelopesIntersect function uses as its intersection Chapter 8 Spatial functions 8 37 envelope All sensitive_areas zone polygons that intersect the interior or boundary of the display window are returned Each polygon is fetched from the result set and passed to the draw_polygon function Get the display window coordinates as a polygon shape get_window amp query_shape_ buf amp query_shape_len Create the SQL expression The envelopesintersect function limits the result set to only those zone polygons that intersect the envelope of the display window sprintf sql_stmt select SE_AsShape zone from sensitive_areas where SE _EnvelopesIntersect zone SE_PolyFromShape 1 Prepare the SQL statement SQLPrepare hstmt UCHAR sql_stmt SQL_NTS Bind the query geometry parameter pcbvaluel query_shape_len SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR query_shape_len 0 query_shape_buf query_shape_len amp pcbvaluel Execute the query rc SQLExecute hstmt Assign the results of the query the Zone polygons to the fetched_shape_buf variable SQLBindCol hstmt 1 SQL_C_BINARY fetched_shape_buf 100000 amp fetched_shape_len Fetch each polygon within the display window and
66. d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the site_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp site_id 0 amp pcbvaluel Bind the name to the second parameter pcbvalue2 name_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR 0 0 name 0 amp pcbvalue2 Bind the location geometry to the third parameter pcbvalue3 location_wkb_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR location_wkb_len 0 location_wkb buf location_wkb_len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The ST_PointN function The ST_PointN function takes an ST_LineString and an INTEGER index and returns a point that is the nth vertex in the ST_LineString s path The numbering of the vertices in the linestring starts with 1 Syntax ST_PointN 1nl ST_LineString index integer Return type ST_Point Chapter 8 Spatial functions 8 91 Example The pointn_test table is created with the gid column which uniquely identifies each row and the In1 ST_LineString column CREATE TABLE pointn_test gid integer Jnl ST_LineString The following INSERT statements insert two linestring values The first linestring does not have Z coordinates or
67. display it while SQL_SUCCESS rc SQLFetch hstmt draw_polygon fetched_shape_buf The ST_Equals function 8 38 The ST_Equals function compares two geometries and returns t TRUE if the geometries are spatially equal otherwise it returns f FALSE Using the ST_Equals function is functionally equivalent to using ST_IsEmpty ST_SymDifference a b The ST_Equals function is computationally intensive and you should consider whether you could use the Equals function instead which does a byte by byte comparison of two objects The Equals function is a system function it is called in SQL statements when you use the operator as shown in the second SELECT statement in the following example To illustrate the difference between ST_Equals and Equals consider the following example CREATE TABLE equal_test id integer line ST_LineString INSERT INTO equal_test VALUES 1 ST_LineFromText linestring 10 10 20 20 1000 INSERT INTO equal_test VALUES 2 ST_LineFromText linestring 20 20 10 10 1000 The following query returns both rows because ST_Equals determines that both linestrings are spatially equivalent IBM Informix Spatial Data User s Guide SELECT id FROM equal_test WHERE ST Equals line ST _LineFromText linestring 10 10 20 20 1000 id 1 2 The following query only returns the first row because Equals only performs a memory comparison of the linestrings
68. do not intersect and the boundary of either geometry intersects the other s interior or boundary At least one geometry must be an ST_LineString ST_Polygon ST_MultiLineString or ST_MultiPolygon type Chapter 7 Determine spatial relationships and transform geometries 7 3 ST_Point ST_LineString ST_LineString ST_LineString e J e e ST_MultiPoint ST_LineString ST_Point ST_Polygon ee y ST_MultiPoint ST_Polygon ST_LineString ST_Polygon Figure 7 4 Touching geometries Related reference The ST_Touches function on page 8 104 The ST_Overlaps function The ST_Overlaps function determines whether two geometries overlap ST_Overlaps returns t TRUE only for geometries of the same dimension and only when their intersection set results in a geometry of the same dimension In other words if the intersection of two ST_Polygon types results in an ST_Polygon then ST_Overlaps returns t TRUE gt ST_LineString ST_LineString ST_Polygon ST_Polygon J e e ST_MultiPoint ST_MultiPoint Figure 7 5 Overlapping geometries Related reference The ST_Overlaps function on page 8 83 The ST_Crosses function The ST_Crosses function determines whether the following pairs of geometries cross each other IBM Informix Spatial Data User s Guide ST_MultiPoint and ST_Polygon ST_MultiPoint and ST_LineString ST_LineString and ST_LineString ST_LineString and ST_Polygon and ST_LineString and ST_M
69. first argument is the GML representation and the second optional argument is the spatial reference identifier to assign to the ST_Geometry For example the ST_GeomFromGML function has the following syntax ST_GeomFromGML gml_string SRID ST_GeomFromGML lt gm1 Point srsName ESPG 1234 srsDimension 2 gt lt gml pos gt 10 02 20 01 lt gml pos gt lt gm1l Point gt 1000 The SE_ASGML and ST_AsGMLJ functions convert the geometry value into a GML representation The ST_EnvelopeAsGMLJ function converts an ST_Polygon into a GML3 Envelope element Chapter 3 Data exchange formats 3 3 Keyhole Markup Language representation 3 4 You can generate a geometry from a Keyhole Markup Language KML representation KML is an XML based schema for expressing geographic annotation and visualization on online maps and earth browsers The following functions generate a geometry from a KML string SE_EnvelopeFromKML The function creates an ST_Polygon from a KML LatLonBox string ST_GeomFromKML The function creates an ST_Geometry from a KML fragment ST_LineFromKML The function creates an ST_LineString from a KML LineString string ST_MLineFromKML The function creates an ST_MultiLineString from a KML MultiGeometry string ST_MPointFromKML The function creates an ST_MultiPoint from a KML MultiGeometry and Point combination string ST_MPolyFromKML The function creates an ST_MultiPolygon from a KML MultiGeom
70. following query shows the resulting spatial_references table entry SELECT FROM spatial_references WHERE srid 1001 srid 1001 description New Zealand lat lon coords auth_name auth_srid falsex 164 6000000000 falsey 49 4000000000 xyunits 127826407 5600 falsez 1000 00000000 zunits 1000 000000000 falsem 1000 00000000 munits 1000 000000000 srtext UNKNOWN See also The SE_CreateSrtext function on page 8 26 Chapter 8 Spatial functions 8 25 Related concepts Select a false origin and system units on page 1 6 The spatial_references table on page 1 5 Related reference The SE_CreateSrtext function The SE_CreateSrtext function The SE_CreateSrtext function returns the OGC well known text representation of a spatial reference system given the ESRI Projection Engine ID number for a coordinate system These ID numbers can be found in the file pedef h which is included in the directory INFORMIXDIR extend spatial version include Syntax SE_CreateSrtext factory_id integer Return type LVARCHAR Example To obtain the spatial reference system text for the 1983 North American Datum EXECUTE FUNCTION SE_CreateSrtext 4269 expression GEOGCS GCS_North_American_1983 DATUM D North American_1983 SP HEROID GRS_1980 6378137 298 257222101 PRIMEM Greenwich 0 U NIT Degree 0 0174532925199432955 Tip You can transfer the output of SE_CreateSrtext directly into th
71. for spatial data Spatial tables require sbspaces to store spatial data and statistics about spatial tables Spatial data is stored in the default sbspace when a geometry exceeds 930 bytes for example a line or polygon with more than 50 vertices The default sbspace is specified by the SBSPACENAME configuration parameter in the onconfig file If you want to store spatial data in a different sbspace use the PUT clause in the CREATE TABLE statement to specify a different sbspace when you create your spatial tables If you do not create a default sbspace or specify a different sbspace when you create a spatial table the database server creates the default sbspace in the root dbspace for the database server To avoid filling up your root dbspace create the default sbspace on a different disk When you create an sbspace for spatial data you can enable the logging of user data By default only smart large object metadata is logged and smart large object user data is not logged Therefore only the metadata can be restored and the user data cannot be restored If you create the spatial data sbspace with logging you can backup and restore the user data as well as the metadata You can create a logged sbspace by using the DF LOGGING ON option of the onspaces utility You can move the smart large object containing metadata about spatial data to a different sbspace by running the ALTER TABLE statement with the PUT clause to specify a different
72. insurance coverage for the town s hospital nursing homes and schools Part of this process includes determining the threat the hazardous waste sites pose to each institution At this time the insurance company wants to consider only those institutions that are not at risk of contamination The GIS consultant hired by the insurance company has been commissioned to locate all institutions that are outside a five mile radius of a hazardous waste storage facility The sensitive_areas table contains several columns that describe the threatened institutions in addition to the zone column which stores the institutions polygon geometries CREATE TABLE sensitive_areas id integer name varchar 128 size float type varchar 10 zone ST Polygon The hazardous_sites table stores the identity of the sites in the site_id and name columns while the actual geographic location of each site is stored in the location point column CREATE TABLE hazardous_sites site_id integer name varchar 40 location ST Point IBM Informix Spatial Data User s Guide The SELECT statement lists the names of all sensitive areas that are outside the five mile radius of a hazardous waste site SELECT sa name FROM sensitive_areas sa hazardous_sites hs WHERE ST Disjoint ST_Buffer hs location 5 5280 sa zone You could also use the ST_Intersects function to perform this query because ST_Intersects and ST_Disjoint return the opposite results
73. is required SELECT gid SE_LocateBetween g1 6 5 7 5 Geometry FROM locatebetween_test gid 1 geometry 1000 MULTILINESTRING M 27 005 19 38 6 5 30 19 18 47 7 38 085 19 6 05 7 5 27 4 22 135 6 5 30 98 23 98 7 36 95 24 98 7 5 gid 2 geometry 1000 MULTIPOINT M 30 19 18 47 7 30 98 23 98 7 Related reference The SE_LocateBetween function on page 7 14 The SE_M function 8 66 The SE_M function returns the measure value of a point Syntax SE_M p1 ST_ Point Return type DOUBLE PRECISION IBM Informix Spatial Data User s Guide Example The m_test table is created with the gid INTEGER column which uniquely identifies the row and the pt1 ST_Point column that stores the sample geometry CREATE TABLE m_test gid integer pt1 ST Point The following INSERT statements insert a point with measures and a point without measures INSERT INTO m_test VALUES 1 gt ST_PointFromText point 10 02 20 01 1000 s INSERT INTO m_test VALUES 2 ST_PointFromText point zm 10 02 20 01 5 0 7 0 1000 s In this query the SE_M function lists the measure values of the points Because the first point does not have measures the SE_M function returns NULL SELECT gid SE_M ptl The measure FROM m_test gid the_measure 1 2 7 000000000000 The SE_Metadatalnit function The SE_MetadataInit function reinitializes the spatial reference system large object and memory cache For comput
74. known text string 6261 Merchich DATUM D_Merchich SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6312 Militar DATUM D_MGI SPHEROID Bessel_1841 6377397 155 299 1528128 Geographische Institut 6264 Mhast DATUM D_Mhast SPHEROID International_1924 6378388 297 6263 Minna DATUM D_Minna SPHEROID Clarke_1880_RGS 6378249 145 293 465 6265 Monte Mario DATUM D_Monte_Mario SPHEROID International_1924 6378388 297 6130 Moznet DATUM D_Moznet SPHEROID WGS_1984 6378137 298 257223563 6266 M poraloko DATUM D_Mporaloko SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6268 NAD Michigan DATUM D_North_American_Michigan SPHEROID Clarke_1866_Michigan 6378450 047 294 978684677 6267 North American DATUM D_North_American_1927 SPHEROID Clarke_1866 Datum 1927 6378206 4 294 9786982 6269 North American DATUM D_North_American_1983 SPHEROID GRS_1980 6378137 Datum 1983 298 257222101 6270 Nahrwan 1967 DATUM D_Nahrwan_1967 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6271 Naparima 1972 DATUM D_Naparima_1972 SPHEROID International_1924 6378388 297 6902 Nord de Guerre DATUM D_Nord_de_Guerre SPHEROID Plessis_1817 6376523 308 64 6318 National Geodetic DATUM D_NGN SPHEROID WGS_1984 6378137 298 257223563 Network Kuwait 6273 NGO 1948 DATUM D_NGO_1948 SPHEROID Bessel_Modified 6377492 018 299 1528128
75. lvarchar SRID integer Return type ST_Point Example The point_test table is created with the single ST_Point column pt1 CREATE TABLE multipoint_test gid smallint mpt1 ST_MultiPoint The ST_PointFromText function converts the point text coordinates to the ST_Point format before the INSERT statement inserts the point into the pt1 column INSERT INTO multipoint_test VALUES 1 ST_MPointFromText multipoint 10 01 20 03 10 52 40 11 30 29 oo 10 74 1000 The ST_PointFromWKB function The ST_PointFromWKB function takes a well known binary representation of type ST_Point and a spatial reference ID to return an ST_Point Syntax ST_PointFromWKB WKB lvarchar SRID integer 8 90 IBM Informix Spatial Data User s Guide Return type ST_Point Example The hazardous sites are stored in the hazardous_sites table created with the CREATE TABLE statement that follows The location column defined as an ST_Point stores a location that is the geographic center of each hazardous site CREATE TABLE hazardous sites site_id integer name varchar 40 location ST Point The program fragment populates the hazardous_sites table Create the SQL insert statement to populate the hazardous_sites table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO hazardous_sites site_id name location VALUES ST PointFromWKB
76. multilinestring while the second is a multipoint INSERT INTO locatealong test VALUES 1 ST_MLineFromText multilinestring m 10 29 19 23 5 23 82 20 29 6 30 19 18 47 7 45 98 20 74 8 23 82 20 29 6 30 98 23 98 7 42 92 25 98 8 1000 INSERT INTO locatealong_test VALUES 2 ST_MPointFromText multipoint m 10 29 19 23 5 23 82 20 29 6 30 19 18 47 7 45 98 20 74 8 23 82 20 29 6 30 98 23 98 7 42 92 25 98 8 1000 In this query the SE_LocateAlong function finds points whose measure is 6 5 The first row returns an ST_MultiPoint containing two points However the second row returns an empty point For linear features geometry with a dimension greater than 0 SE_LocateAlong can interpolate the point but for multipoints the target measure must match exactly SELECT gid SE_locatealong g1 6 5 Geometry FROM locatealong_test gid il geometry 1000 MULTIPOINT M 27 005 19 38 6 5 27 4 22 135 6 5 gid 2 geometry 1000 POINT M EMPTY In this query the SE_LocateAlong function returns a multipoint for both rows The target measure of 7 matches measures in the multilinestring and multipoint source data SELECT gid SE_locatealong gl 7 Geometry FROM locatealong_ test gid 1 geometry 1000 MULTIPOINT M 30 19 18 47 7 30 98 23 98 7 gid 2 geometry 1000 MULTIPOINT M 30 19 18 47 7 30 98 23 98 7 Related reference The SE_LocateAlong function on page 7 13 The SE_LocateBetween function The SE_L
77. non intersected endpoints Chapter 2 Spatial data types 2 7 e 3 is a non simple ST_MultiLineString because the interior of one of its ST_LineString elements is intersected The boundary of this ST_MultiLineString is the three non intersected endpoints e 4 is a simple non closed ST_MultiLineString It is not closed because its element ST_LineStrings are not closed It is simple because none of the interiors of any of the element ST_LineStrings intersect e 5 is a simple closed ST_MultiLineString It is closed because all its elements are closed It is simple because none of its elements intersect at the interiors DAS 2 OS Figure 2 4 Examples of ST_MultiLineString objects Functions The following functions operate on ST_MultiLineStrings ST_Length The function returns the cumulative length of all its ST_LineString elements as a double precision number ST_IsClosed The function returns t TRUE if the ST_MultiLineString is closed and f FALSE otherwise ST_MultiPolygon data type 2 8 The ST_MultiPolygon data type defines features such as a forest stratum or a non contiguous parcel of land such as an island chain Properties The boundary of an ST_MultiPolygon is the cumulative length of its elements exterior and interior rings The interior of an ST_MultiPolygon is defined as the cumulative interiors of its element ST_Polygons The boundary of an ST_MultiPolygon s elements can only intersect at a tangent
78. not accessible to ArcSDE and other ESRI client tools Use the ESRI shp2sde command to load data if you want to access it using ESRI client tools Data loaded using the loadshp utility is accessible to client programs that do not depend on ESRI system tables other than the OGC standard geometry_columns and spatial_references tables Related reference Insert data into a spatial column on page 1 9 Create a spatial index on page 1 11 The infoshp utility gt gt infoshp 0 V The infoshp utility reports information extracted from headers of the shp shx and dbf files that make up ESRI shapefiles It also detects the presence of optional prj files that may be associated with ESRI shapefiles and reports the coordinate system information The infoshp utility can check for spatial_references table entries that are qualified to load one or more shapefiles If no spatial reference exists that can be used to load the specified shapefiles the infoshp utility can create a new entry in the spatial_references table for loading the shapefiles Syntax Y filename gt lt Info Info f Copyright IBM Corp 2001 2010 A 1 Info Info info sheis 0 database create s server u username p password Operation modes You use the o flag to set the operation mode for the infoshp command Set the o flag to one of the following options check Checks for spatial_refere
79. parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO species_sitings species genus sitings VALUES SE_MpointFromShape d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the species to the first parameter pcbvaluel species_len rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR species_len 0 species species len amp pcbvaluel Bind the genus to the second parameter pcbvalue2 genus_len IBM Informix Spatial Data User s Guide rc SQLBindParameter hstmt 2 SQL PARAM INPUT SQL_C_CHAR SQL_CHAR genus_len 0 genus genus_len amp pcbvalue2 Bind the sitings geometry to the third parameter pcbvalue3 sitings_shape_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR sitings_shape_len 0 sitings shape buf sitings shape _len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The ST_MPointFromText function The ST_MPointFromText function creates an ST_MultiPoint from a well known text representation of type ST_MultiPoint and a spatial reference ID Syntax ST_MPointFromText WKT lvarchar SRID integer Return type ST_MultiPoint Example The multipoint_test table is created with the single ST_MultiPoint mpt1 column CREATE TABLE multipoint
80. point In addition to the other properties inherited from the superclass ST_Geometry ST_MultiPolygons have area The following figure shows examples of ST_MultiPolygon 1 is ST_MultiPolygon with two ST_Polygon elements The boundary is defined by the two exterior rings IBM Informix Spatial Data User s Guide and the three interior rings 2 is an ST_MultiPolygon with two ST_Polygon elements The boundary is defined by the two exterior rings and the two interior rings The two ST_Polygon elements intersect at a tangent point Figure 2 5 Examples of ST_MultiPolygon objects Functions The following functions that operate on ST_MultiPolygons ST_Area The function returns the cumulative area of its ST_Polygon elements as a double precision number ST_Centroid The function returns an ST_Point that is the center of an ST_MultiPolygon s envelope ST_PointOnSurface The function returns an ST_Point that is guaranteed to be on the surface of one of its ST_Polygon elements Locale override The external text representation of double precision numbers in spatial data types follows the U S English locale en_us 8859 1 In this standard all text input must use dots as decimal separators and must be single byte ASCII regardless of the locale Internally the database server overrides the current locale with the U S English locale For example in many European locales the decimal separator is a comma You can ke
81. spatial constraints The IBM Informix WFS includes a CGI client program and an IBM Informix server side function to let web programs send requests to IBM Informix for geographical features These geographical features are encoded in the platform independent XML based geography markup language GML You can use WFS with the IBM Informix spatial data types or the Geodetic DataBlade module to enable IBM Informix database servers to manage geographical features WFS is written to the Open Geospatial Consortium OGC standard in document 04 094 Web Feature Service Implementation Specification Version 1 1 0 For more information see the IBM Informix Database Extensions User s Guide and the OGC website at http www opengeospatial org IBM Informix Spatial Data User s Guide Chapter 2 Spatial data types IBM Informix spatial data types are divided into two categories the base geometry subclasses and the homogeneous collection subclasses e The base geometries are ST_Point ST_LineString ST_Polygon e The homogeneous collections are ST_MultiPoint ST_MultiLineString ST_MultiPolygon Homogeneous collections are collections of base geometries in addition to sharing base geometry properties homogeneous collections also have some properties of their own The ST_GeometryType function takes an ST_Geometry and returns the instantiable subclass in the form of a character string The ST_NumGeometries function ta
82. tables on page 1 7 Chapter 3 Data exchange formats on page 3 1 Preparing to use spatial data Before you can create a spatial table you must prepare the database server To prepare the database server for spatial data 1 Set the STACKSIZE configuration parameter in the onconfig file to 64 Increasing the stack size prevents stack overflow errors 2 If necessary create a default sbspace and set the SBSPACENAME configuration parameter in the onconfig file If you do not have a default sbspace when you Chapter 1 Getting started with spatial data 1 3 1 4 create spatial tables the database server creates one in the root dbspace and dynamically sets the SBSPACENAME configuration parameter 3 If necessary create the system sbspace and set the SYSSBSPACENAME configuration parameter in the onconfig file The value of the SYSSBSPACENAME configuration parameter can be the same as the value of the SBSPACENAME configuration parameter If you do not have a system sbspace when you create spatial tables the database server creates one in the root dbspace and dynamically sets the SYSSBSPACENAME configuration parameter 4 Restart the database server to enable the changes to the onconfig file Related reference LH SYSSBSPACENAME Configuration Parameter Administrator s Reference L ISBSPACENAME Configuration Parameter Administrator s Reference L STACKSIZE Configuration Parameter Administrator s Reference Sbspaces
83. the database until the data is loaded One option for loading data is to use the loadshp utility This utility allows you to copy data from ESRI shapefiles to an IBM Informix database A companion utility unloadshp allows you to unload data from a database to shapefiles Important The loadshp utility does not add information to ESRI system tables such as the layers table Therefore data loaded with the loadshp utility is not accessible to ArcSDE and other ESRI client tools Use the ESRI shp2sde command to load data if you want to access it using ESRI client tools Data loaded using the loadshp utility is accessible to client programs that do not depend on ESRI system tables other than the OGC standard geometry_columns and spatial_references tables Another option is to develop your own loader application The source code for two sample programs load_wkb and load_shapes is supplied with the IBM Informix software These programs illustrate how to convert data into OGC well known binary and ESRI shapefile formats The programs can be modified and linked into existing applications They are located under the INFORMIXDIR extend spatial version examples directory ESQL C and ODBC versions of both programs are provided Alternatively you can acquire data from a vendor and load the data through the ESRI SDE server The shp2sde command loads shapefiles into an existing table Accessing spatial tables through SDE software also provides immediate a
84. the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each part in the PolyLineM are stored end to end The points for part 2 follow the points for part 1 and so on The parts array holds the array index of the starting point for each part There is no delimiter in the points array between parts M Range The minimum and maximum measures for the PolyLineM stored in the order Mmin Mmax M Array An array of length NumPoints The measures for each part in the PolyLineM are stored end to end The measures for part 2 follow the measures for part 1 and so on The parts array holds the array index of the starting point for each part There is no delimiter in the measure array between parts The following table shows PolyLineM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 23 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer Num Parts Little endian Byte X Points Points Point NumPoints Little endian Byte Y Mmin Mmin Double 1 Little endian Byte Y 8 Mmax Mmax Double 1 Little endian Byte Y 16 M Array M Array Double NumPoints Little endian Tip X 44 4 NumParts Y X 16 NumPoints PolygonM A PolygonM consists of a number of rings A ring is a closed non self intersecting loop
85. to have the same spatial reference system as the other and resubmit the function USE24 Incompatible geometries in function FUNCTION Explanation The function expected two geometries of a certain type and did not receive them User response __Review the syntax of the function described in Chapter 8 Spatial functions on page 8 1 correct the geometry and resubmit the function USE25 Subscript SUBSCRIPT out of range in function FUNCTION Explanation The function has detected that the subscript entered is outside the allowable range of values For instance the ST_PointN Q function returns the nth point identified by the index parameter If a negative value 0 or a number greater than the number of points in the source linestring were entered this error message would be returned User response Correct the subscript value and resubmit the function USE26 Subtype mismatch received subtype TYPE1 expected subtype TYPE2 Explanation This error can occur when you try to insert a geometry of one subtype into a column of a different subtype for example an ST_Point into an ST_LineString column User response To insert more than one subtype into a column make that a column of type ST_Geometry USE27 Unknown or unsupported geometry data structure version YVERSION found in FUNCTION Explanation Future versions of the Spatial DataBlade may not be able to interpret geome
86. translate and scale your data prior to storage If you change these values you will be unable to retrieve your original floating point coordinate data Related reference The SE_CreateSRID function on page 8 24 Work with spatial tables These topics describe how to create tables with spatial columns how to insert and update spatial data and how to create indexes on spatial columns Related concepts Overview of using spatial data on page 1 2 Create a spatial table A spatial table is a table that includes one or more spatial columns To create a spatial table include a spatial column in the column clause of the CREATE TABLE statement You should create your spatial tables in a logged database A spatial column can only accept data of the type required by the spatial column For example a column of ST_Polygon type rejects integers characters and even other types of geometry In addition to the geometry column ESRI client software also requires a unique key the se_row_id INTEGER column Chapter 1 Getting started with spatial data 1 7 1 8 Consider the sensitive areas and hazardous waste sites example Stored in the sensitive_areas table are schools hospitals and playgrounds while the hazardous_sites table holds locations of hazardous waste sites The ST_Polygon data type is used to store the sensitive areas while hazardous sites are stored as points using the ST_Point type CREATE TABLE sensitive_areas s
87. waterways table is created with the ID and name columns that identify each stream and river system stored in the table The water column is an ST_MultiLineString because the river and stream systems are often an aggregate of several linestrings CREATE TABLE waterways id integer name varchar 128 water ST MultiLineString Chapter 8 Spatial functions 8 71 This code fragment populates the waterways table with a unique ID a name and a water ST_MultiLineString Create the SQL insert statement to populate the waterways table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO waterways id name water VALUES ST_MlineFromWKB d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL _C_SLONG SQL_INTEGER 0 0 amp id 0 amp pcbvaluel Bind the name to the second parameter pcbvalue2 name_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR name_len 0 name name_len amp pcbvalue2 Bind the water geometry to the third parameter pcbvalue3 water_wkb_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR water_wkb_len 0 water_wkb_buf water_wkb_len amp
88. zone_wkb_ buf zone_wkb_len amp pcbvalue5 Execute the insert statement rc SQLExecute hstmt The ST_Polygon function The ST_Polygon function generates an ST_Polygon from a ring an ST_LineString that is both simple and closed Syntax ST Polygon 1n ST_LineString Return type ST_Polygon Example The following CREATE TABLE statement creates the polygon_test table which has a single column p1 CREATE TABLE polygon_test pl ST_polygon The INSERT statement converts a ring an ST_LineString that is both closed and simple into an ST_Polygon and inserts it into the p1 column using the ST_LineFromText function within the ST_Polygon function INSERT INTO polygon_test VALUES ST_Polygon ST_LineFromText linestring 10 01 20 03 20 94 ade 35 93 10 04 10 01 20 03 1000 The ST_Relate function The ST_Relate function compares two geometries and returns 1 TRUE if the geometries meet the conditions specified by the DE 9IM pattern matrix string otherwise 0 FALSE is returned Syntax ST_Relate gl ST Geometry g2 ST Geometry patternMatrix lvarchar Return type BOOLEAN Example A DE 9IM pattern matrix is a device for comparing geometries There are several types of such matrices For example the equals pattern matrix will tell you if any two geometries are equal Chapter 8 Spatial functions 8 97 In this example an equals pattern matrix shown below is read left to right and top
89. 0012 Longitude Of Center PARAMETER Longitude_Of_Center 75 100013 Longitude Of 1st Point PARAMETER Longitude_Of_1st_Point 0 100014 Longitude Of 2nd Point PARAMETER Longitude_Of_2nd_Point 60 100020 Central Parallel PARAMETER Central_Parallel 0 100021 Latitude Of Origin PARAMETER Latitude_Of_Origin 0 100022 Latitude Of Center PARAMETER Latitude_Of_Center 40 100023 Latitude Of 1st Point PARAMETER Latitude_Of_1st_Point 0 100024 Latitude Of 2nd Point PARAMETER Latitude_Of_2nd_Point 60 100025 Standard Parallel 1 PARAMETER Standard_Parallel_1 60 100026 Standard Parallel 2 PARAMETER Standard_Parallel_2 60 100027 Pseudo Standard Parallel 1 PARAMETER Pseudo_Standard_Parallel_1 60 100037 X Scale PARAMETER X_Scale 1 100038 Y Scale PARAMETER Y_Scale 1 100039 XY Plane Rotation PARAMETER XY_Plane_Rotation 0 100040 X Axis Translation PARAMETER X_Axis_Translation 0 100041 Y Axis Translation PARAMETER Y_Axis_Translation 0 100042 Z Axis Translation PARAMETER Z_Axis_Translation 0 100043 X Axis Rotation PARAMETER X_Axis_Rotation 0 100044 Y Axis Rotation PARAMETER Y_Axis_Rotation 0 100045 Z Axis Rotation PARAMETER Z_Axis_Rotation 0 100046 Scale Difference PARAMETER Scale_Difference 0 100047 Dataset Name PARAMETER Dataset_ 0 Map projections IBM Informix spatial data types support many map projections The following table lists a representative sample of the map projections supported
90. 1E 06 9112 Centesimal minute 1 100th Gon UNIT Minute_Centesimal 0 0001570796326794897 Grad 9113 Centesimal second 1 10000th UNIT Second_Centesimal 1 570796326794897E 06 Gon Grad 9114 Mil angle subtended by 1 6400 UNIT Mil_6400 0 0009817477042468104 circle B 4 IBM Informix Spatial Data User s Guide Geodetic spheroids IBM Informix spatial data types support many geodetic spheriods The following table lists a representative sample of the geodetic spheroids supported by the IBM Informix spatial data types For a complete list of supported geodetic spheroids see the file INFORMIXDIR extend spatial version include pedef h Table B 3 Geodetic spheriods Factory ID Description OGC well known text string 7001 Airy 1830 SPHEROID Airy_1830 6377563 396 299 3249646 7002 Airy modified SPHEROID Airy_Modified 6377340 189 299 3249646 7041 Average Terrestrial System SPHEROID ATS_1977 6378135 298 257 1977 7003 Australian National SPHEROID Australian 6378160 298 25 7004 Bessel 1841 SPHEROID Bessel_1841 6377397 155 299 1528128 7005 Bessel modified SPHEROID Bessel_Modified 6377492 018 299 1528128 7006 Bessel Namibia SPHEROID Bessel_Namibia 6377483 865 299 1528128 7007 Clarke 1858 SPHEROID Clarke_1858 6378293 639 294 260676369 7008 Clarke 1866 SPHEROID Clarke_1866 6378206 4 294 9786982 7009 Clarke 1866 Michigan SPHEROID
91. 2 gt lt gml pos gt 10 32 23 98 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gm PointMember gt lt gml Point srsName DEFAULT srsDimension 2 gt lt gm pos gt 11 92 25 64 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gml MultiPoint gt 1000 INSERT INTO geometry_test VALUES 55 ST_GeomFromGML lt gm MultiLineString srsName DEFAULT srsDimension 2 gt lt gml LineStringMember gt lt gml LineString srsName DEFAULT srsDimension 2 gt lt gml posList dimension 2 gt 10 02 20 01 10 32 23 98 11 92 25 64 lt gml posList gt lt gml LineString gt lt gml LineStringMember gt lt gml LineStringMember gt lt gml LineString srsName DEFAULT srsDimension 2 gt lt gml posList dimension 2 gt 9 55 23 75 15 36 30 11 lt gml posList gt lt gml LineString gt IBM Informix Spatial Data User s Guide lt gml LineStringMember gt lt gml MultiLineString gt 1000 INSERT INTO geometry_test VALUES 6 ST_GeomFromGML lt gm MultiPolygon srsName DEFAULT srsDimension 2 gt lt gm PolygonMember gt lt gml Polygon srsName DEFAULT srsDimension 2 gt lt gml exterior gt lt gm LinearRing gt lt gml posList dimension 2 gt 10 02 20 01 19 15 33 94 25 02 34 15 11 92 35 64 10 02 20 01 lt gml posList gt lt gml LinearRing gt lt gml exterior gt lt gm1 Polygon gt lt gm1 PolygonMember gt lt gm Pol ygonMember gt lt gml Pol
92. 20 01 15 36 30 11 9 55 30 11 9 55 20 01 10 02 20 01 73 36 20 01 73 36 35 64 10 02 35 64 10 02 20 01 See also The SE_BoundingBox function on page 8 18 The ST_EnvelopeAsGML function The ST_EnvelopeAsGMLJ function takes a geometry value returned by ST_Envelope and generates a GML3 Envelope element Syntax ST_EnvelopeAsGML p ST Geometry Return type ST_Geometry Example ST_EnvelopeFromGML ST_Envelope ST_LineFromText LINESTRING 1 2 3 4 1003 Output lt gml Envelope srsName EPSG 1234 gt lt gml lowerCorner gt 1 2 lt gml lowerCorner gt lt gml upperCorner gt 3 4 lt gml upperCorner gt lt gml Envelope gt Chapter 8 Spatial functions 8 35 The SE_EnvelopeAsKML function The SE_EnvelopeAsKML function takes a geometry value returned by ST_Envelope and returns it as a KML LatLonBox Syntax SE_EnvelopeAsKML p ST_ Geometry Return type ST_Geometry Example EXECUTE FUNCTION SE_EnvelopeAsKML ST_PolyFromText POLYGON 124 21160602 25 8373769872 67 1589579416 25 8373769872 67 1589579416 49 384359066 124 21160602 49 384359066 124 21160602 25 8373769872 3 Output lt LatLonBox gt lt north gt 49 384359066 lt north gt lt south gt 25 8373769872 lt south gt lt east gt 67 1589579416 lt east gt lt west gt 124 21160602 lt west gt lt LatLonBox gt The ST_EnvelopeFromGML function The ST_EnvelopeFromGML function takes a GML2 or GML
93. 298 257222101 potential model 6036 GRS 1967 DATUM D_GRS_1967 SPHEROID GRS_1967 6378160 298 247167427 6019 GRS 1980 DATUM D_GRS_1980 SPHEROID GRS_1980 6378137 298 257222101 6020 Helmert 1906 DATUM D_Helmert_1906 SPHEROID Helmert_1906 6378200 298 3 6021 Indonesian DATUM D_Indonesian SPHEROID Indonesian 6378160 298 247 National 6022 International 1927 DATUM D_International_1924 SPHEROID International_1924 6378388 297 6023 International 1967 gt DATUM D_International_1967 SPHEROID International_1967 6378160 298 25 6024 Krasovsky 1940 DATUM D_Krasovsky_1940 SPHEROID Krasovsky_1940 6378245 298 3 6025 Transit precise DATUM D_NWL_9D SPHEROID NWL_9D 6378145 298 25 ephemeris 6032 OSU 1986 geoidal DATUM D_OSU_86F SPHEROID OSU_86F 6378136 2 298 25722 model 6033 OSU 1991 geoidal DATUM D_OSU_91A SPHEROID OSU_91A 6378136 3 298 25722 model 6027 Plessis 1817 DATUM D_Plessis_1817 SPHEROID Plessis_1817 6376523 308 64 6035 Authalic sphere DATUM D_Sphere SPHEROID Sphere 6371000 0 6028 Struve 1860 DATUM D_Struve_1860 SPHEROID Struve_1860 6378298 3 294 73 6029 War Office DATUM D_War_Office SPHEROID War_Office 6378300 583 296 106001 WGS 1966 DATUM D_WGS_1966 SPHEROID WGS_1966 6378145 298 25 B 7 Appendix B OGC well known text representation of spatial reference systems Table B 4 Spheroid horizontal datums continued Factory ID Desc
94. 3 string representation of an envelope and an optional spatial reference ID and returns a geometry object If the srsName attribute is specified in the GML string then a corresponding entry in the spatial_references table must exist unless it is specified as UNKNOWN or DEFAULT Syntax ST_EnvelopeFromGML gml_string lvarchar ST_EnvelopeFromGML gml_string lvarchar SRID integer Return type A four sided ST_Polygon representing the envelope Example ST_EnvelopeFromGML lt gm Envelope gt lt gml lowerCorner gt 180 0 90 0 lt gml lowerCorner gt lt gml upperCorner gt 180 0 90 0 lt gml upperCorner gt lt gml Envelope gt 1003 The SE_EnvelopeFromKML function The SE_EnvelopeFromKML function takes a KML LatLonBox or LatLonAltBox and an optional spatial reference ID and returns a polygon 8 36 IBM Informix Spatial Data User s Guide The LatLonBox and LatLonAltBox contain four coordinates north south east and west that are used to form the traditional pair of SW NE coordinates usually found with bounding boxes LatLonAltBox also contains the elements minAltitude and maxAltitude and while those will be accepted as valid tags in the KML fragment they are not used to form a Z polygon Only 2 D polygons are returned Syntax SE_EnvelopeFromKML kml_string lvarchar SE_EnvelopeFromKML kml_string lvarchar SRID integer Return type A four sided ST_Polygon representing the envelope Example In this exa
95. 37587 9063 Link Benoit 1895 B UNIT Link_Benoit_1895_B 0 2011678249437587 9070 Foot 1865 UNIT Foot_1865 0 3048008333333334 9080 Indian geodetic foot UNIT Foot_Indian 0 3047995102481469 9081 Indian foot 1937 UNIT Foot_Indian_1937 0 30479841 9082 Indian foot 1962 UNIT Foot_Indian_1962 0 3047996 9083 Indian foot 1975 UNIT Foot_Indian_1975 0 3047995 9084 Indian yard UNIT Yard_Indian 0 9143985307444408 9085 Indian yard 1937 UNIT Yard_Indian_1937 0 91439523 9086 Indian yard 1962 UNIT Yard_Indian_1962 0 9143988 9087 Indian yard 1975 UNIT Yard_Indian_1975 0 9143985 Angular units IBM Informix spatial data types support many angular units The following table shows a representative sample of the angular units of measure supported by the IBM Informix spatial data types For a complete list of supported angular units of measure see the file INFORMIXDIR extend spatial version include pedef h Table B 2 Angular units Factory ID Description OGC well known text string 9101 Radian UNIT Radian 1 9102 Degree UNIT Degree 0 0174532925199433 9103 Arc minute UNIT Minute 0 0002908882086657216 9104 Arc second UNIT Second 4 84813681109536E 06 9105 Grad angle subtended by 1 400 UNIT Grad 0 01570796326794897 circle 9106 Gon angle subtended by 1 400 UNIT Gon 0 01570796326794897 circle 9109 Microradian le 6 radian UNIT Microradian
96. 378137 298 257222101 6247 La Canoa DATUM D_La_Canoa SPHEROID International_1924 6378388 297 6249 Lake DATUM D_Lake SPHEROID International_1924 6378388 297 6250 Leigon DATUM D_Leigon SPHEROID Clarke_1880_RGS 6378249 145 293 465 6251 Liberia 1964 DATUM D_Liberia_1964 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6207 Lisbon DATUM D_Lisbon SPHEROID International_1924 6378388 297 6126 Lithuania 1994 DATUM D_Lithuania_1994 SPHEROID GRS_1980 6378137 298 257222101 6288 Loma Quintana DATUM D_Loma_Quintana SPHEROID International_1924 6378388 297 6252 Lome DATUM D_Lome SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6253 Luzon 1911 DATUM D_Luzon_1911 SPHEROID Clarke_1866 6378206 4 294 9786982 6903 Madrid 1870 DATUM D_Madrid_1870 SPHEROID Struve_1860 6378298 3 294 73 6128 Madzansua DATUM D_Madzansua SPHEROID Clarke_1866 6378206 4 294 9786982 superseded by Tete 6256 Mahe 1971 DATUM D_Mahe_1971 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6257 Makassar DATUM D_Makassar SPHEROID Bessel_1841 6377397 155 299 1528128 6259 Malongo 1987 DATUM D_Malongo_1987 SPHEROID International_1924 6378388 297 6260 Manoca DATUM D_Manoca SPHEROID Clarke_1880_RGS 6378249 145 293 465 6262 Massawa DATUM D_Massawa SPHEROID Bessel_1841 6377397 155 299 1528128 B 10 IBM Informix Spatial Data User s Guide Table B 5 Horizontal datums continued Factory ID Description OGC well
97. 45 2559999343 10 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gml PointMember gt lt gml Point srsName EPSG 4326 srsDimension 3 gt lt gml pos gt 99 86 33 84 20 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gml MultiPoint gt INSERT INTO gml_pointtest VALUES 3 ST_MPointFromGML lt gml MultiPoint srsName EPSG 4326 srsDimension 4 gt lt gml PointMember gt lt gml Point srsName EPSG 4326 srsDimension 4 gt lt gml pos gt 109 47999994 46 4600005499 10 58 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gm PointMember gt lt gml Point srsName EPSG 4326 srsDimension 4 gt lt gm1 pos gt 99 45 33 256 10 54 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gml MultiPoint gt The first record specifies a spatial reference ID of 4 WGS84 and a default dimension of 2 The second and third records contain Z and M measures and pass the spatial reference ID through the srsName attribute Output SELECT FROM gml_pointtest gid 1 mpt1 4 MULTIPOINT 110 449999933 45 2559999343 99 4499999329 33 2559999343 gid 2 mpt1 4 MULTIPOINT Z 110 449999933 45 2559999343 10 99 8600000805 33 840000 0201 20 gid 3 mptl 4 MULTIPOINT ZM 109 47999994 46 4600005499 10 58 99 4499999329 33 255 9999343 10 54 3 row s retrieved The ST_MPointFromKML function The ST_MPointFromKML function takes a KML MultiGeometry and Point combinati
98. 5 Horizontal datums continued Factory ID Description OGC well known text string 6131 Indian 1960 DATUM D_Indian_1960 SPHEROID Everest_Adjustment_1937 6377276 345 300 8017 6155 Dabola DATUM D_Dabola SPHEROID Clarke_1880_RGS 6378249 145 293 465 6156 S JTSK DATUM D_S_JTSK SPHEROID Bessel_1841 6377397 155 299 1528128 6165 Bissau DATUM D_Bissau SPHEROID International_1924 6378388 297 106101 Estonia 1937 DATUM D_Estonia_1937 SPHEROID Bessel_1841 6377397 155 299 1528128 106102 Hermannskogel DATUM D_Hermannskogel SPHEROID Bessel_1841 6377397 155 299 1528128 106103 Sierra Leone 1960 DATUM D_Sierra_Leone_1960 SPHEROID Clarke_1880_RGS 6378249 145 293 465 106201 European 1979 DATUM D_European_1979 SPHEROID International_1924 6378388 297 106202 Everest Bangladesh DATUM D_Everest_Bangladesh SPHEROID Everest_Adjustment_1937 6377276 345 300 8017 106203 Everest India and DATUM D_Everest_India_Nepal Nepal SPHEROID Everest_Definition_1962 6377301 243 300 8017255 106204 Hjorsey 1955 DATUM D_Hjorsey_1955 SPHEROID International_1924 6378388 297 106205 Hong Kong 1963 DATUM D_Hong_Kong_1963 SPHEROID International_1924 6378388 297 106206 Oman DATUM D_Oman SPHEROID Clarke_1880_RGS 6378249 145 293 465 106207 South Asia Singapore DATUM D_South_Asia_Singapore SPHEROID Fisc
99. 6297 Tananarive 1925 DATUM D_Tananarive_1925 SPHEROID International_1924 6378388 297 6127 Tete DATUM D_Tete SPHEROID Clarke_1866 6378206 4 294 9786982 6298 Timbalai 1948 DATUM D_Timbalai_1948 SPHEROID Everest_Definition_1967 6377298 556 300 8017 6299 TM65 DATUM D_TM65 SPHEROID Airy_Modified 6377340 189 299 3249646 6300 TM75 DATUM D_TM75 SPHEROID Airy_Modified 6377340 189 299 3249646 6301 Tokyo DATUM D_Tokyo SPHEROID Bessel_1841 6377397 155 299 1528128 6302 Trinidad 1903 DATUM D_Trinidad_1903 SPHEROID Clarke_1858 6378293 639 294 260676369 6303 Trucial Coast 1948 DATUM D_Trucial_Coast_1948 SPHEROID Helmert_1906 6378200 298 3 6304 Voirol 1875 DATUM D_Voirol_1875 SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6305 Voirol Unifie 1960 DATUM D_Voirol_Unifie_1960 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6322 WGS 1972 DATUM D_WGS_1972 SPHEROID WGS_1972 6378135 298 26 6324 WGS 1972 Transit DATUM D_WGS_1972_BE SPHEROID WGS_1972 6378135 298 26 Broadcast Ephemeris 6326 WGS 1984 DATUM D_WGS_1984 SPHEROID WGS_1984 6378137 298 257223563 6309 Yacare DATUM D_Yacare SPHEROID International_1924 6378388 297 6310 Yoff DATUM D_Yoff SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6311 Zanderij DATUM D_Zanderij SPHEROID International_1924 6378388 297 6600 Anguilla 1957 DATUM D_Anguilla_1957 SPHEROID Clarke_1880_RGS 6378249 145 293 465 B 12 IBM Informix Spatial Data U
100. 67 SPHEROID International_1924 6378388 297 106227 Santo DOS 1965 DATUM D_Santo_DOS_1965 SPHEROID International_1924 6378388 297 106228 Viti Levu 1916 DATUM D_Viti_Levu_1916 SPHEROID Clarke_1880_RGS 6378249 145 293 465 B 14 IBM Informix Spatial Data User s Guide Table B 5 Horizontal datums continued Factory ID Description OGC well known text string 106229 Wake Eniwetok 1960 DATUM D_Wake_Eniwetok_1960 SPHEROID Hough_1960 6378270 297 106230 Wake Island Astro DATUM D_Wake_Island_1952 SPHEROID International_1924 6378388 297 1952 106231 Anna 1 Astro 1965 DATUM D_Anna_1_1965 SPHEROID Australian 6378160 298 25 106232 Gan 1970 DATUM D_Gan_1970 SPHEROID International_1924 6378388 297 106233 ISTS 073 Astro 1969 DATUM D_ISTS_073_1969 SPHEROID International_1924 6378388 297 106234 Kerguelen Island DATUM D_Kerguelen_Island_1949 SPHEROID International_1924 1949 6378388 297 106235 Reunion DATUM D_Reunion SPHEROID International_1924 6378388 297 106237 Ascension Island DATUM D_Ascension_Island_1958 SPHEROID International_1924 1958 6378388 297 106238 Astro DOS 71 4 DATUM D_DOS_71_4 SPHEROID International_1924 6378388 297 106239 Cape Canaveral DATUM D_Cape_Canaveral SPHEROID Clarke_1866 6378206 4 294 9786982 106240 Fort Thomas 1955 DATUM D_Fort_Thomas_1955 SPHEROID Clarke_1880_RGS 63
101. 78249 145 293 465 106241 Graciosa Base SW DATUM D_Graciosa_Base_SW_1948 SPHEROID International_1924 1948 6378388 297 106242 ISTS 061 Astro 1968 DATUM D_ISTS_061_1968 SPHEROID International_1924 6378388 297 106243 L C 5 Astro 1961 DATUM D_LC5_1961 SPHEROID Clarke_1866 6378206 4 294 9786982 106245 Observ DATUM D_Observ_Meteorologico_1939 Meteorologico 1939 SPHEROID International_1924 6378388 297 106246 Pico de Las Nieves DATUM D_Pico_de_Las_Nieves SPHEROID International_1924 6378388 297 106247 Porto Santo 1936 DATUM D_Porto_Santo_1936 SPHEROID International_1924 6378388 297 106249 Sao Braz DATUM D_Sao_Braz SPHEROID International_1924 6378388 297 106250 Selvagem Grande DATUM D_Selvagem_Grande_1938 SPHEROID International_1924 1938 6378388 297 106251 Tristan Astro 1968 DATUM D_Tristan_1968 SPHEROID International_1924 6378388 297 106252 American Samoa DATUM D_Samoa_1962 SPHEROID Clarke_1866 6378206 4 294 9786982 1962 106253 Camp Area Astro DATUM D_Camp_Area SPHEROID International_1924 6378388 297 106254 Deception Island DATUM D_Deception_Island SPHEROID Clarke_1880_RGS 6378249 145 293 465 106255 Gunung Segara DATUM D_Gunung_ Segara SPHEROID Bessel_1841 6377397 155 299 1528128 106257 S 42 Hungary DATUM D_S42_ Hungary SPHEROID Krasovsky_1940 6378245 298 3 106260 Alaskan Islands DATUM D_Alaskan_Islands SPHEROID Clarke_1866 6378206 4 294 9786982 106261 Hong
102. 9 1528128 6235 Guyane Francaise DATUM D_Guyane_Francaise SPHEROID International_1924 6378388 297 6255 Herat North DATUM D_Herat_North SPHEROID International_1924 6378388 297 6254 Hito XVIII 1963 DATUM D_Hito_XVIHI_1963 SPHEROID International_1924 6378388 297 6236 Hu Tzu Shan DATUM D_Hu_Tzu_Shan SPHEROID International_1924 6378388 297 6237 Hungarian Datum DATUM D_Hungarian_1972 SPHEROID GRS_1967 6378160 298 247167427 1972 6239 Indian 1954 DATUM D_Indian_1954 SPHEROID Everest_Adjustment_1937 6377276 345 300 8017 6240 Indian 1975 DATUM D_Indian_1975 SPHEROID Everest_Adjustment_1937 6377276 345 300 8017 6238 Indonesian Datum DATUM D_Indonesian_1974 SPHEROID Indonesian 6378160 298 247 1974 6241 Jamaica 1875 DATUM D_Jamaica_1875 SPHEROID Clarke_1880 6378249 138 293 466307656 6242 Jamaica 1969 DATUM D_Jamaica_1969 SPHEROID Clarke_1866 6378206 4 294 9786982 6243 Kalianpur 1880 DATUM D_Kalianpur_1880 SPHEROID Everest_1830 6377299 36 300 8017 6244 Kandawala DATUM D_Kandawala SPHEROID Everest_Adjustment_1937 6377276 345 300 8017 6245 Kertau DATUM D_Kertau SPHEROID Everest_1830_Modified 6377304 063 300 8017 6123 Kartastokoordinaatti DATUM D_KKJ SPHEROID International_1924 6378388 297 jarjestelma 6246 Kuwait Oil Company DATUM D_Kuwait_Oil_Company SPHEROID Clarke_1880_RGS 6378249 145 293 465 6319 Kuwait Utility DATUM D_Kuwait_Utility SPHEROID GRS_1980 6
103. 9 4799999397 36 4600000469 10 99 8600000805 33 8400000201 20 gid 3 Inl 4 MULTILINESTRING ZM 110 449999933 45 2559999343 10 54 109 47999994 4 6 4600005499 10 58 109 86000008 43 8400000201 20 64 99 4499999329 33 2559999343 10 54 99 4799999397 36 4600000469 10 58 99 8600000805 33 84 00000201 20 64 3 row s retrieved The ST_MLineFromKML function The ST_MLineFromKML function takes a KML MultiLineString string and an optional spatial reference ID and returns a multipart polyline object A KML MultiLineString string can contain the KML shape attributes lt extrude gt lt tessellate gt and lt altitudeMode gt but they are ignored in the ST_MultiLineString representation Syntax ST_MLineFromKML kmlstring lvarchar ST_MLineFromKML kmlstring lvarchar SRID integer Return type ST_MultiLineString Example EXECUTE FUNCTION ST_MLineFromKML lt MultiGeometry gt lt LineString gt lt coordinates gt 122 4425587930444 37 80666418607323 0 122 4428379594768 37 80663578323093 0 lt coordinates gt lt LineString gt lt LineString gt Chapter 8 Spatial functions 8 69 lt coordinates gt 122 4425509770566 37 80662588061205 0 122 4428340530617 37 8065999493009 0 lt coordinates gt lt LineString gt lt MultiGeometry gt 4 The SE_MLineFromShape function 8 70 The SE_MLineFromShape function creates an ST_MultiLineString from a shape of type polyline and a spatial refe
104. 957 DATUM D_Bermuda_1957 SPHEROID Clarke_1866 6378206 4 294 9786982 6217 Bern 1898 DATUM D_Bern_1898 SPHEROID Bessel_1841 6377397 155 299 1528128 6306 Bern 1938 DATUM D_Bern_1938 SPHEROID Bessel_1841 6377397 155 299 1528128 6218 Bogota DATUM D_Bogota SPHEROID International_1924 6378388 297 6219 Bukit Rimpah DATUM D_Bukit_Rimpah SPHEROID Bessel_1841 6377397 155 299 1528128 6220 Camacupa DATUM D_Camacupa SPHEROID Clarke_1880_RGS 6378249 145 293 465 6221 Campo Inchauspe DATUM D_Campo_Inchauspe SPHEROID International_1924 6378388 297 6222 Cape DATUM D_Cape SPHEROID Clarke_1880_Arc 6378249 145 293 466307656 6223 Carthage DATUM D_Carthage SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6224 Chua DATUM D_Chua SPHEROID International_1924 6378388 297 6315 Conakry 1905 DATUM D_Conakry_1905 SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6225 Corrego Alegre DATUM D_Corrego_Alegre SPHEROID International_1924 6378388 297 6226 Cote d Ivoire DATUM D_Cote_d_Ivoire SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6274 Datum 73 DATUM D_Datum_73 SPHEROID International_1924 6378388 297 6227 Deir ez Zor DATUM D_Deir_ez_Zor SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6316 Dealul Piscului 1933 DATUM D_Dealul_Piscului_1933 SPHEROID International_1924 6378388 297 6317 Dealul Piscului 1970 DATUM D_Dealul_Piscului_1970 SPHEROID Krasovsky_1940 6378245 298 3 6314 Deutsche DATUM
105. Appendix G Error messages Spatial DataBlade functions that generate any of these errors will abort Likewise if a Spatial DataBlade function is part of a transaction the transaction also aborts Error message parameters marked with percent signs for example are replaced with appropriate values in the actual message text Error messages and their explanations USE01 Unable to establish a connection in FUNCTION Explanation The IBM Informix server unexpectedly returned a null value instead of a connection handle when the function attempted to connect to the server The function was unable to determine the exact cause of the error User response If this error continues to occur contact IBM Informix Technical Support for assistance 7USE02 Function FUNCTION is unable to allocate memory Explanation The function could not allocate the memory that it requires User response Ensure that your hardware meets the minimum memory requirements specified in the IBM Informix installation guide Also make sure that you have not overallocated memory to the IBM Informix server or other applications Consider increasing the amount of your hardware physical memory USE03 Invalid geometry in FUNCTION Explanation The parameters entered into the function have produced an invalid geometry User response Check the parameters and review Chapter 2 Spatial data types on page 2 1 for a description of valid geo
106. AsGML function is defined as LVARCHAR You can write user defined routines UDRs in C or SPL to extend the functionality of the existing spatial data type functions You can use the SE_AsGMLJ function to convert an ST_Geometry type to its GML representation Syntax SE_ASGML p ST_Geometry Return type ST_Geometry Example In this example the SE_AsGML function converts the location column of the table mytable into its GML description CREATE TABLE mytable id integer location ST Point INSERT INTO mytable VALUES EEE 10 02 20 01 1000 SELECT SE_AsGML location FROM mytable WHERE id 1 lt gml Point srsName UNKNOWN gt lt gm coord gt lt gm X gt 10 02 lt gm1 X gt lt gml Y gt 20 01 lt gm1 Y gt lt gm1 coord gt lt gml Point gt The INFORMIXDIR extend spatial version examples gml directory contains more information about how to use an XML parser to validate the results of this function The ST_ASGML function The ST_AsGMLJ function returns the Geography Markup Language GML representation of an ST_Geometry spatial type that conforms to either the GML2 or GMLS3 standard Typically you use the ST_AsGML function to retrieve the GML representation of a spatial primitive from the server and send it to a client specifying the GML version to use For example SELECT ST_AsGML geomcol 3 FROM mytable Syntax ST_ASGML p ST Geometry int Version Version is the GML version that i
107. BM Informix Spatial Data User s Guide A geocentric coordinate system is quite similar to a geographic coordinate system It is represented by lt geocentric cs gt GEOCCS lt name gt lt datum gt lt prime meridian gt lt linear unit gt You can use the SE_CreateSrtext function to assist you in constructing these spatial reference system text strings The remainder of this appendix shows the OGC well known text building blocks of spatial reference systems that are supported by the IBM Informix spatial data types These text strings can be generated by the SE_CreateSrtext function you use the factory ID number in the first column of the table as the input argument to SE_CreateSrtext Related reference The SE_CreateSrtext function on page 8 26 Linear units IBM Informix spatial data types support many linear units The following table shows a representative sample of the linear units of measure supported by the IBM Informix spatial data types For a complete list of supported linear units of measure see the file INFORMIXDIR extend spatial version include pedef h Table B 1 Linear units of measure Factory ID Description OGC well known text string 9001 International meter UNIT Meter 1 9002 International foot UNIT Foot 0 3048 9003 US survey foot UNIT Foot_US 0 3048006096012192 9005 Clarke s foot UNIT Foot_Clarke 0
108. CETEMP parameter in your onconfig file e Spatial data need not be presorted BOTTOM_UP_BUILD yes Creates a more compact index in less time BOUNDING_BOX_INDEX yes Does not require a temporary dbspace NO_SORT yes e Spatial data must be presorted Related reference The SE_Spatialkey function on page 8 99 Bottom up versus top down index builds R tree indexes are created using one of two options top down build or bottom up build When an index is built from the top down spatial objects are inserted into the R tree one at a time Objects are grouped together in the R tree according to their spatial proximity to one another When an index is built from the bottom up objects are first sorted according to a numeric value which is generated by the SE_SpatialKey function Then the R tree is built by inserting all objects into the leaf pages the bottom level of the tree in sorted order and then building a hierarchy of bounding boxes above the leaf pages An R tree index can be built much more quickly from the bottom up than from the top down typically 10 to 20 times faster This increased speed comes at a price you must create a temporary dbspace of sufficient size to sort all the spatial data in the table To determine the size use the following formula Size in bytes Number of rows in table 1000 Refer to your IBM Informix Administrator s Guide for more information about dbspaces The NO_SORT op
109. Error messages and their explanations G1 Appendix H Accessibility a a 2 ew ee ee ee ee ee ee AT Accessibility features for IBM Informix products H 1 Accessibility features oog H 1 Keyboard navigation koni H 1 Related accessibility information H 1 IBM and accessibility H 1 Dotted decimal syntax diagrams H 1 Notices l 1 Trademarks 1 3 Index X 1 viii IBM Informix Spatial Data User s Guide Introduction This introduction provides an overview of the information in this publication and describes the conventions it uses About this publication This publication contains information to assist you in using the IBM Informix spatial extension with IBM Informix The IBM Informix spatial extension adds custom data types and supporting routines to the server This section discusses the organization of the publication the intended audience and the associated software products that you must have to develop and use the IBM Informix spatial extension General information about the Informix spatial extension is available at http www ibm com software data informix blades patial Types of users This publication is written for the following audience e Developers who design the tables to hold spatial information in IBM Informix databases e Developers who write applications to access spatial information stored in IBM Informix databases Assumptions about your locale IBM Informix p
110. Generates the convex hull of a geometry The ST_ConvexHull function on page 8 2 Generates the bounding box of a geometry The ST_Envelope function on page 8 3 Generates a geometry with fewer vertices but of the same general shape The SE_Generalize function on page 8 4 gs v IQ oO T p Ww D o ea N e e Generates an ST_MultiPoint representing points that have the specified measure value The SE_LocateAlong function on page 8 6 l Generates an ST_MultiPoint or ST_MultiLineString representing points or paths that have measures in the specified range The SE_LocateBetween unction on page 8 65 ER Appends a vertex to a linestring The SE_VertexAppend unction on page 8 109 ER Deletes a vertex from a geometry The SE_VertexDelete function on page 8 10 Updates a vertex in a geometry The SE_VertexUpdate function on page 8 10 Manage collections Nearest neighbor queries Returns the nth geometry The ST_GeometryN function on page 8 41 Returns the number of geometries in the collection Retrieves nearby geometries in increasing distance order SE_NearestBbox is similar to SE_Nearest but measures distances between bounding boxes of geometries The ST_NumGeometries unction on page 8 81 The SE_Nearest and SE_NearestBbox functions on ER Chapter 8 Sp
111. Horizontal datums spheroid only IBM Informix spatial data types support many spheriod horizontal datums The following table lists a representative sample of the horizontal datums spheroid only supported by the IBM Informix spatial data types For a complete list of supported horizontal datums spheroid only see the file INFORMIXDIR extend spatial version include pedef h Table B 4 Spheroid horizontal datums Factory ID Description OGC well known text string 6001 Airy 1830 DATUM D_Airy_1830 SPHEROID Airy_1830 6377563 396 299 3249646 6002 Airy modified DATUM D_Airy_Modified SPHEROID Airy_Modified 6377340 189 299 3249646 6003 Australian DATUM D_Australian SPHEROID Australian 6378160 298 25 National 6004 Bessel 1841 DATUM D_Bessel_1841 SPHEROID Bessel_1841 6377397 155 299 1528128 6005 Bessel modified DATUM D_Bessel_Modified SPHEROID Bessel_Modified 6377492 018 299 1528128 6006 Bessel Namibia DATUM D_Bessel_Namibia SPHEROID Bessel_Namibia 6377483 865 299 1528128 6007 Clarke 1858 DATUM D_Clarke_1858 SPHEROID Clarke_1858 6378293 639 294 260676369 6008 Clarke 1866 DATUM D_Clarke_1866 SPHEROID Clarke_1866 6378206 4 294 9786982 B 6 IBM Informix Spatial Data User s Guide Table B 4 Spheroid horizontal datums continued Factory ID Description OGC well known
112. INSERT INTO ring_linestring VALUES Bis ST_LineFromText linestring 15 47 30 12 20 73 22 12 10 83 14 13 16 45 17 24 21 56 13 37 11 23 22 56 19 11 26 78 15 47 30 12 1000 The query returns the results of the ST_IsRing function The first and third rows return 0 because the linestrings are not rings while the second row returns 1 because it is a ring SELECT gid ST_IsRing Inl Is_it_a_ring FROM ring_linestring gid is_it_a_ring 1 f 2 t 3 f The ST_IsSimple function 8 58 The ST_IsSimple function returns t TRUE if the geometry object is simple otherwise it returns f FALSE Properties of geometries are described in Properties of spatial data types on page 2 1 Syntax ST_IsSimple gl ST_Geometry Return type BOOLEAN IBM Informix Spatial Data User s Guide Example The table issimple_test is created with two columns The pid column is a SMALLINT containing the unique identifier for each row The g1 ST_Geometry column stores the simple and nonsimple geometry samples CREATE TABLE issimple test pid smallint gl ST Geometry The following INSERT statements insert two records into the issimple_test table The first is a simple linestring because it does not intersect its interior The second is non simple because it does intersect its interior INSERT INTO issimple_test VALUES i ST_LineFromText linestring 10 10 20 20 30 30 1000 s INSERT INTO issimple_test VALUES 2 ST_Lin
113. Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumPoints NumPoints Integer 1 Little endian Byte 40 Points Points Point NumPoints Little endian Byte X Zmin Zmin Double 1 Little endian Byte X 8 Zmax Zmax Double 1 Little endian Byte X 16 Z Array Z Array Double NumPoints Little endian Tip X 40 16 NumPoints PolyLineZ A PolyLineZ consists of one or more parts A part is a connected sequence of two or more points Parts may or may not be connected to one another Parts may or may not intersect one another The following fields are for a PolyLineZ Box The bounding box for the PolyLineZ stored in the order Xmin Ymin Xmax Ymax NumParts The number of parts in the PolyLineZ NumPoints The total number of points for all parts Parts An array of length NumParts Stores for each part the index of its first point in the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each part in the PolyLineZ are stored end to end The points for part 2 follow the points for part 1 and so on The parts array holds the array index of the starting point for each part There is no delimiter in the points array between parts IBM Informix Spatial Data User s Guide Z Range The minimum and maximum Z values for the PolyLineZ stored in the order Zmin Zmax Z Array An array of length NumPoints The Z values for each part in the PolyLineZ are stored end to end T
114. J INSERT INTO dimension_test VALUES Linestring ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO dimension_test VALUES Polygon ST_PolyFromText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 s INSERT INTO dimension_test VALUES Multipoint ST_MPointFromText multipoint 10 02 20 01 10 32 23 98 11 92 25 64 1000 s INSERT INTO dimension_test VALUES Multilinestring ST_MLineFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 s INSERT INTO dimension_test VALUES Multipolygon Chapter 8 Spatial functions 8 29 ST_MPolyFromText multipolygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 J The SELECT statement lists the subclass name stored in the geotype column with the dimension of that geotype SELECT geotype ST_Dimension gl Dimension FROM dimension_test geotype dimension Point Linestring Polygon Multipoint Multilinestring Multipolygon NrONrF The ST_Disjoint function 8 30 The ST_Disjoint function takes two geometries and returns t TRUE if the two geometries are completely non intersecting otherwise it returns f FALSE Syntax ST_Disjoint gl ST Geometry g2 ST_Geometry Return type BOOLEAN Example An insurance company wants to assess the
115. LineString gt lt gml LineStringMember gt lt gml MultiLineString gt IBM Informix Spatial Data User s Guide INSERT INTO gml_linetest VALUES 3 ST_MLineFromGML lt gm MultiLineString srsName EPSG 4326 srsDimension 4 gt lt gml LineStringMember gt lt gml LineString srsName EPSG 4326 srsDimension 4 gt lt gml posList dimension 4 gt 110 449999933 45 2559999343 10 54 109 47999994 46 4600005499 10 58 109 86000008 43 8400000201 20 64 lt gm1 posList gt lt gml LineString gt lt gml LineStringMember gt lt gml LineStringMember gt lt gml LineString srsName EPSG 4326 srsDimension 4 gt lt gml posList dimension 4 gt 99 45 33 256 10 54 99 48 36 46 10 58 99 86 33 84 20 64 lt gml posList gt lt gml LineString gt lt gml LineStringMember gt lt gml MultiLineString gt The first record specifies a spatial reference ID of 4 WGS84 and a default dimension of 2 The second and third records contain Z and M measures and pass the spatial reference ID through the srsName attribute Output SELECT FROM gml_linetest gid 1 Inl 4 MULTILINESTRING 110 449999933 45 2559999343 109 47999994 46 4600000 469 109 86000008 43 8400000201 99 4499999329 33 2559999343 99 47999 99397 36 4600000469 99 8600000805 33 8400000201 gid 2 Inl 4 MULTILINESTRING Z 110 449999933 45 2559999343 10 109 47999994 46 46 00005499 10 109 86000008 43 8400000201 20 99 4499999329 33 2559999343 10 9
116. M value IBM Informix Spatial Data User s Guide Functions The following functions operate solely on the ST_Point data type ST_X The function returns a point data type s X coordinate value as a double precision number ST_Y The function returns a point data type s Y coordinate value as a double precision number SE_Z The function returns a point data type s Z coordinate value as a double precision number SE_M The function returns a point data type s M coordinate value as a double precision number ST_LineString data type The ST_LineString data type is a one dimensional object stored as a sequence of points defining a linear interpolated path ST_LineString types are often used to define linear features such as roads rivers and power lines Properties An ST_LineString is simple if it does not intersect its interior The endpoints the boundary of a closed ST_LineString occupy the same point in space An ST_LineString is a ring if it is both closed and simple In addition to properties inherited from the superclass ST_Geometry ST_LineString values have length The endpoints normally form the boundary of a ST_LineString unless the ST_LineString is closed in which case the boundary is NULL The interior of a ST_LineString is the connected path that lies between the endpoints unless it is closed in which case the interior is continuous The following figure shows examples of ST_LineString objects 1 is a sim
117. Note that intersections are calculated in XY space not in XYM space A PolygonM may contain multiple outer rings The rings of a PolygonM are referred to as its parts The following fields are for a PolygonM Box The bounding box for the PolygonM stored in the order Xmin Ymin Xmax Yma NumParts The number of rings in the PolygonM IBM Informix Spatial Data User s Guide NumPoints Parts Points The total number of points for all rings An array of length NumParts Stores for each ring the index of its first point in the points array Array indexes are numbered with respect to 0 An array of length NumPoints The points for each ring in the PolygonM are stored end to end The points for Ring 2 follow the points for Ring 1 and so on The parts array holds the array index of the starting point for each ring There is no delimiter in the points array between rings M Range The minimum and maximum measures for the PolygonM stored in the order Mmin Mmax M Array An array of length NumPoints The measures for each ring in the PolygonM are stored end to end The measures for Ring 2 follow the measures for Ring 1 and so on The parts array holds the array index of the starting measure for each ring There is no delimiter in the measure array between rings The following are important notes about PolygonM shapes e The rings are closed the first and last vertex of a ring must be the same e The order of rings in th
118. ON MySpatialFunc ST_AsText geomcol lvarchar Syntax ST_AsText gl ST Geometry Return type ST_Geometry Example The ST_AsText function converts the hazardous_sites location point into its text description CREATE TABLE hazardous sites site_id integer name varchar 40 location ST_Point INSERT INTO hazardous_sites VALUES 102 W H Kleenare Chemical Repository ST_PointFromText point 1020 12 324 02 1000 SELECT site_id name ST_AsText location Location FROM hazardous_sites site_id 102 name W H Kleenare Chemical Repository location POINT 1020 12 324 02 The ST_Boundary function 8 16 The ST_Boundary function takes a geometry object and returns its combined boundary as a geometry object Syntax ST_Boundary gl ST Geometry Return type ST_Geometry IBM Informix Spatial Data User s Guide Example In this example the boundary_test table is created with two columns geotype defined as a VARCHAR and g1 defined as the superclass ST_Geometry The INSERT statements that follow insert each one of the subclass geometries The ST_Boundary function retrieves the boundary of each subclass stored in the g1 geometry column Note that the dimension of the resulting geometry is always one less than the input geometry Points and multipoints always result in a boundary that is an empty geometry dimension 1 Linestrings and multilinestrings return a multipoint boundary dimension 0 A polygon or mult
119. R name_len 0 name name_len amp pcbvalue2 Bind the water geometry to the third parameter pcbvalue3 water_shape_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY IBM Informix Spatial Data User s Guide SQL_INFX_UDT_LVARCHAR water_shape_len 0 water_shape_buf water_shape_len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The ST_MLineFromText function The ST_MLineFromText function takes a well known text representation of type ST_MultiLineString and a spatial reference ID and returns an ST_MultiLineString Syntax ST_MLineFromText wkt lvarchar SRID integer Return type ST_MultiLineString Example The mlinestring_test is created with the gid SMALLINT column that uniquely identifies the row and the ml1 ST_MultiLineString column CREATE TABLE mlinestring test gid smallint ml1 ST MultiLineString The following INSERT statement inserts the ST_MultiLineString with the ST_MLineFromText function INSERT INTO mlinestring_test VALUES 1 ST_MLineFromText multilinestring 10 01 20 03 10 52 40 11 30 29 41 56 31 78 10 74 20 93 20 81 21 52 40 10 1000 The ST_MLineFromWKB function The ST_MLineFromWKB function creates an ST_MultiLineString from a well known binary representation of type ST_MultiLineString and a spatial reference ID Syntax ST_MLineFromWKB WKB Ivarchar SRID integer Return type ST_MultiLineString Example The
120. REATE TABLE statement CREATE TABLE sde spatial_references srid integer NOT NULL description varchar 64 auth_name varchar 255 auth_srid integer falsex float NOT NULL falsey float NOT NULL xyunits float NOT NULL falsez float NOT NULL zunits float NOT NULL falsem float NOT NULL munits float NOT NULL 8 100 IBM Informix Spatial Data User s Guide srtext char 2048 NOT NULL PRIMARY KEY srid CONSTRAINT sde sp_ref_pk s Before you can create geometry and insert it into a table you must enter the SRID of that geometry into the spatial_references table This is a sample insert of a spatial reference system The spatial reference system has an SRID value of 1 a false X Y of 0 0 and its system units are 100 The Z coordinate and measure offsets are 0 while the Z coordinate and measure units are 1 INSERT INTO spatial_references srid description auth_name auth _srid falsex falsey xyunits falsez zunits falsem munits srtext VALUES 1 NULL NULL NULL 0 0 100 0 1 0 1 UNKNOWN Important Choose the parameters of a spatial _ references table entry with care See The spatial_references table on page 1 5 for more information The following table is created for this example CREATE TABLE srid_test gl ST Geometry In the next statement an ST_Point geometry located at coordinate 10 01 50 76 is inserted into the geometry column g1 When the ST_Point geometry is created by the ST_P
121. RIMEM Ferro 17 66666666666667 8908 Jakarta 106 48 27 79 E PRIMEM Jakarta 106 8077194444444 8902 Lisbon 9 07 54 862 W PRIMEM Lisbon 9 131906111111112 8905 Madrid 3 41 16 58 W PRIMEM Madrid 3 687938888888889 8913 Oslo 10 43 22 5 E PRIMEM Oslo 10 72291666666667 8903 Paris 2 20 14 025 E PRIMEM Paris 2 337229166666667 8906 Rome 12 27 08 4 E PRIMEM Rome 12 45233333333333 8911 Stockholm 18 03 29 8 E PRIMEM Stockholm 18 05827777777778 Projection parameters IBM Informix spatial data types support many projection parameters The following table lists a representative sample of the projection parameters supported by the IBM Informix spatial data types For a complete list of supported projection parameters see the file INFORMIXDIR extend spatial version include pedef h Table B 7 Projection parameters Factory ID Description OGC well known text string 100001 False Easting PARAMETER False_Easting 0 100002 False Northing PARAMETER False_Northing 0 100003 Scale Factor PARAMETER Scale_Factor 1 100004 Azimuth PARAMETER Azimuth 45 100010 Central Meridian PARAMETER Central_Meridian 0 B 16 IBM Informix Spatial Data User s Guide Table B 7 Projection parameters continued Factory ID Description OGC well known text string 100011 Longitude Of Origin PARAMETER Longitude_Of_Origin 0 10
122. S co Takes a well known binary representation and The ST_MPointFromWKB returns an ST_MultiPoint unction on page 8 7 nl Ol Takes a well known binary representation and The ST_MPolyFromWKB returns an ST_MultiPolygon unction on page 8 7 nl Ko Generate a geometry from an Takes an ESRI shape representation and returns The SE_ShapeToSQL function ESRI shape representation an ST_Geometry using SRID 0 on page 8 9 Takes an ESRI shape representation and returns The SE_GeomFromShape an ST_Geometry unction on page 8 4 En oN Takes an ESRI shape representation and returns The SE_PointFromShape an ST_Point unction on page 8 8 En Ke Takes an ESRI shape representation and returns The SE_LineFromShape an ST_LineString unction on page 8 6 N Takes an ESRI shape representation and returns The SE_PolyFromShape an ST_Polygon unction on page 8 9 ms Takes an ESRI shape representation and returns The SE_MLineFromShape an ST_MultiLine unction on page 8 7 En Takes an ESRI shape representation and returns The SE_MPointFromShape an ST_MultiPoint unction on page 8 7 IN Takes an ESRI shape representation and returns The SE_MPolyFromShape an ST_MultiPolygon unction on page 8 7 nl oo 8 2 IBM Informix Spatial Data User s Guide Table 8 1 Spatial functions by task type continued Function task type Description Function name G
123. SELECT sa name FROM sensitive_areas sa hazardous_sites hs WHERE NOT ST_Intersects ST Buffer hs location 5 5280 sa zone The following figure shows that the nursing home is the only sensitive area for which the ST_Disjoint function will return t TRUE when comparing sensitive sites to the five mile radius of the hazardous waste sites The ST_Disjoint function returns t whenever two geometries do not intersect in any way Wl Hospital y H School Nursing Home Figure 8 5 Sensitive Sites and Hazardous Waste Sites Related reference The ST_Disjoint function on page 7 2 The ST_Disjoint function on page 7 17 The SE_Dissolve function The SE_Dissolve function is an aggregate function that computes the union of geometries of the same dimension if there is just one geometry that satisfies your query it is returned unaltered Syntax SE Dissolve g1 ST Geometry Return type ST_Geometry Chapter 8 Spatial functions 8 31 Example The following example creates a single multipolygon from the individual hexagons inserted into the honeycomb table CREATE TABLE honeycomb cell_id int hex_cell ST Polygon INSERT INTO honeycomb VALUES 1 O polygon 5 10 7 7 10 7 12 10 10 13 7 13 5 10 INSERT INTO honeycomb VALUES 2 polygon 12 4 15 4 17 7 15 10 12 10 10 7 12 4 INSERT INTO
124. SRI shapefile Syntax gt gt unloadshp 0 Init Mode gt lt Append Mode H Init mode init 1 tablename colname f filename D database 7 gt s server gt gt u username Paes 4 shape type a a where claise gt log EP Append mode append tablename colname f filename D database 7 gt s server T u username p password w where_clause log J directory Operation modes You use the o flag to set the operation mode for the unloadshp command Set the o flag to one of the following options append Spatial features are appended to the existing ESRI shapefile specified by the f option init Spatial features are unloaded into a newly created ESRI shapefile Command line switches You can use the unloadshp command flags to specify the following options D The database name f The path and name of the shapefile l The table and geometry column from which to extract data The table and column must exist and the executing user must either own the table or have access to it A 6 IBM Informix Spatial Data User s Guide log optional Specifies whether to write information about the status of data loading to a log file The log file has the same name as the shapefile you are loading into with the extension log If you do n
125. ST Polygon The hazardous sites are stored in the following hazardous_sites table The location column defined as a point stores the geographic center of each hazardous site CREATE TABLE hazardous sites site_id integer name varchar 40 location ST_Point The sensitive_areas and hazardous_sites tables are joined by the ST_Overlaps function which returns t TRUE for all sensitive_areas rows whose zone polygons overlap the buffered five mile radius of the hazardous_sites location point SELECT sa name hs name FROM sensitive_areas sa hazardous_sites hs WHERE ST Overlaps sa zone ST Buffer hs location 26400 name Johnson County Hospital name Landmark Industrial name Summerhill Elementary School name Landmark Industrial The following figure shows that some of the sensitive areas in this administrative district lie within the five mile buffer radius of the hazardous site locations It is clear that both buffers intersect the hospital and one intersects the school The Chapter 8 Spatial functions 8 19 nursing home lies safely outside both radii Hospital MAU CS School Nursing Home Figure 8 2 Sensitive areas Related reference The ST_Buffer function on page 7 12 The ST_Centroid function 8 20 The ST_Centroid function takes a polygon or multipolygon and returns its ge
126. Spatial functions 8 61 Syntax ST_LineFromKML kmlstring lvarchar ST_LineFromKML kmlstring lvarchar SRID integer Return type ST_LineString Example EXECUTE FUNCTION ST_LineFromKML lt LineString gt lt coordinates gt 130 597293 50 678292 0 129 733457 50 190606 0 130 509877 49 387208 0 128 801553 48 669761 0 129 156745 47 858658 0 128 717835 47 739997 0 lt coordinates gt lt LineString gt 4 Output expression 4 LINESTRING Z 130 597292947 50 6782919759 0 129 733456972 50 1906059982 0 130 509877068 49 3872080751 0 128 801553066 48 669761042 0 129 156744951 47 8586579701 0 128 717834948 47 7399970362 0 The SE_LineFromShape function The SE_LineFromShape function takes a shape of type polyline and a spatial reference ID to return an ST_LineString A polyline with only one part is appropriate as an ST_LineString and a polyline with multiple parts is appropriate as an ST_MultiLineString see The SE_MLineFromShape function on page 8 70 Syntax SE_LineFromShape s1 lvarchar SRID integer Return type ST_LineString Example The sewerlines table is created with three columns sewer_id which uniquely identifies each sewer line the INTEGER class column which identifies the type of sewer line generally associated with the line s capacity and the sewer ST_LineString column which stores the sewer line geometry CREATE TABLE sewerlines sewer_id integer class integer sewer ST_Lin
127. Temporary buffers used for processing spatial data are allocated from the per_routine memory pool and are not reused between UDR invocations Several memory buffers are typically allocated and freed for every row in a table that is being processed n Enables memory buffer reuse This is the default value Temporary buffers are allocated from the per_command memory pool As they are freed they are returned to a pool and are reused for subsequent memory requests This pool is drained when the UDR sequence completes which is after all rows in a table are processed N Disables memory buffer reuse but allocate all temporary buffers from the server per_command memory pool This mode in conjunction with the DONTDRAINPOOLS server environment variable has an effect similar to mode 1 but lets the server manage the memory Buffers that hold UDR return values are allocated from the per_command memory pool and are reused between UDR invocations The ST MEMMODE environment variable must be set before the server starts If you change the value of the environment variable you must restart the server To override an existing value without restarting the server you can also change the value of a parameter called MemMode MemMode is a parameter that takes the same values as the ST MEMMODE environment variable Unlike the environment variable you can set the value of MemMode at any time using the SE_ParamSet function as described in SE_ParamSet
128. Tip The loadshp utility described in Appendix A Load and unload shapefile foe on pee ao ta on page A 1 automatically creates these entries in the geometry_columns table The ESRI shp2sde command also does this Insert data into a spatial column You can copy data into or out of the database using the traditional external geometry formats or latitude and longitude based geometry formats These geometry formats include e IBM Informix load format e OGC well known text representation WKT e OGC well known binary representation WKB e ESRI shapefile format e Geography Markup Language GML e Keyhole Markup Language KML Except for the IBM Informix load format all of these formats require the use of input and output conversion functions to insert spatial data into and retrieve data from a database You use spatial data type functions to convert data into its stored data types for each of these formats For example in the SQL statements below records are inserted into the sensitive_areas and hazardous_sites table The ST_PolyFromText function converts the well known text representation of a polygon into an ST_Polygon type before inserting it into the ZONE column of the sensitive_areas table Likewise the ST_PointFromText function converts the well known text representation of a point into an ST_Point type before inserting it into the LOCATION column of the hazardous_sites table You can also enter data in ESRI shapefi
129. Tip X 44 4 NumParts Y X 16 NumPoints Measured shape types in XYZ space These topics describe shapes with X Y and Z coordinates that also have measure values PointZM A PointZM consists of a quadruplet of double precision coordinates in the order X Y Z M The following table shows PointZM byte stream contents Position Byte 0 Byte 4 Byte 12 Byte 20 Byte 28 Field Shape Type ZNK Value ZNKXxH Type Integer Double Double Double Double Number oo j ar jld Byte order Little endian Little endian Little endian Little endian Little endian MultiPointZM A MultiPointZM represents a set of PointZMs as follows e The bounding box is stored in the order Xmin Ymin Xmax Ymax e The bounding Z range is stored in the order Zmin Zmax e The bounding M range is stored in the order Mmin Mmax E 10 IBM Informix Spatial Data User s Guide The following table shows MultiPointZM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 18 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumPoints NumPoints Integer 1 Little endian Byte 40 Points Points Point NumPoints Little endian Byte X Zmin Zmin Double 1 Little endian Byte X 8 Zmax Zmax Double 1 Little endian Byte X 16 Z Array Z Array Double NumPoints Little endian Byte Y Mmin Mmin Double 1 Little endian Byte Y 8 Mmax Mmax Double 1 Little endian Byte Y 16 M Arra
130. _PointOnSurface function generates a point that is guaranteed to be on the surface of the building footprints SELECT building_id ST_PointOnSurface footprint FROM buildingfootprints building_id 506 expression 1000 POINT 12 5 49 5 building_id 543 expression 1000 POINT 32 52 5 building id 1208 expression 1000 POINT 12 5 27 5 building_id 178 expression 1000 POINT 32 30 The ST_PolyFromGML function The ST_PolyFromGML function takes a GML2 or GML3 string representation of an ST_Polygon and an optional spatial reference ID and returns a polygon object Syntax ST_PolyFromGML gmlstring lvarchar ST_PolyFromGML gmlstring lvarchar SRID integer Return type ST_Polygon Example The test_poly table is created with the INTEGER column id and the ST_Polygon column geom CREATE TABLE test_poly id INTEGER geom ST Polygon INSERT INTO test_poly VALUES 1 ST_PolyFromGML lt gm1 Polygon srsName EPSG 4326 srsDimension 2 gt lt gml exterior gt lt gml LinearRing gt lt gml posList dimension 2 gt 84 36 32 49 82 66 32 69 82 15 32 46 83 09 33 08 83 37 33 19 84 36 32 49 lt gml posList gt lt gml LinearRing gt lt gml exterior gt lt gml Polygon gt 4 This record specifies a spatial reference id of 4 WGS84 and represents a two dimensional six sided polygon Output SELECT FROM test_poly id l geom 4 POLYGON 84 3600000805 32 4900000536 82 6599999799 32 6899999866
131. _VertexUpdate function changes the value of a vertex in a geometry You must supply both the exact old value and the new value of the vertex to be altered If the input geometry has Z values or measures you must supply them as well All vertices in the geometry which match the old value will be updated Chapter 8 Spatial functions 8 109 Syntax SE_VertexUpdate ST_Geometry old ST Point new ST Point Return type ST_Geometry The ST_Within function 8 110 The ST_Within function returns t TRUE if the first object is completely within the second otherwise it returns f FALSE Syntax ST_Within gl ST Geometry g2 ST Geometry Return type BOOLEAN Example In the example two tables are created buildingfootprints contains a city s building footprints while the other lots contains its lots The city engineer wants to make sure that all the building footprints are completely inside their lots In both tables the ST_MultiPolygon data type stores the ST_Geometry of the building footprints and the lots The database designer selected ST_MultiPolygon for both features because a lot can be separated by a natural feature such as a river and a building footprint can be made up of several buildings CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon CREATE TABLE lots lot_id integer lot ST_MultiPolygon The city engineer first retrieves the buildings that are not comp
132. _Within function 7 5 8 110 ST_WKBToSQL function 8 111 ST_WKTToSQL function 8 112 ST_X function 2 4 8 113 ST_Y function 2 4 8 114 ST_Zmax function 8 115 ST_Zmin function 8 115 STACKSIZE configuration parameter 1 3 standards xi Storage space 6 1 Strategy functions 4 4 Subclass data types 2 1 Syntax diagrams reading in a screen reader H 1 SYSSBSPACENAME configuration parameter 1 3 System units 1 7 T Table fragmentation 5 1 Tessellating 7 15 Top down index build 4 3 Transformation functions 7 12 Triggers 1 5 U Unloading data A 1 unloadshp utility A 1 A 6 V Visual disabilities reading syntax diagrams H 1 Index X 3 W Well known binary representation 3 2 D 1 Well known text representation 3 1 B 1 C 1 modified C 4 X XDR D 1 converting to NDR D 1 XYunits 1 5 Z Z coordinates 2 4 3 2 X 4 IBM Informix Spatial Data User s Guide Printed in USA SC27 3547 00 aping sjasp eyeq jeneds xiuuojuy NGI OL LE UOISIaA X wojul Wal gt UOLPEWNOJUL JULAS
133. _test gid smallint mpt1 ST_MultiPoint The following INSERT statement inserts a multipoint into the mpt1 column using the ST_MPointFromText function INSERT INTO multipoint_test VALUES l ST_MPointFromText multipoint 10 01 20 03 10 52 40 11 30 29 41 56 31 78 10 74 1000 The ST_MPointFromWKB function The ST_MPointFromWKB function creates an ST_MultiPoint from a well known binary representation of type ST_MultiPoint and a spatial reference ID Syntax ST_MPointFromWKB WKB lvarchar SRID integer Return type ST_MultiPoint Example The species_sitings table is created with three columns The species and genus columns uniquely identify each row while the sitings ST_MultiPoint stores the locations of the species sightings Chapter 8 Spatial functions 8 75 CREATE TABLE species_sitings species varchar 32 genus varchar 32 sitings ST_MultiPoint This code fragment populates the species_sitings table Create the SQL insert statement to populate the species_sitings table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO species_sitings species genus sitings VALUES ST_MpointFromWKB d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the species to the first parameter pcbvaluel species_len rc SQLB
134. _test VALUES Multipolygon ST_MPolyFromText multipolygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 The SELECT statement lists the subclass name stored in the geotype column and the convex hull SELECT geotype ST_ConvexHul l g1 convexhul1 FROM convexhull_test Related reference The ST_ConvexHull function on page 7 14 The ST_CoordDim function The ST_CoordDim function returns the coordinate dimensions of the ST_Geometry value For example a point with a Z coordinate has three dimensions and a point with a Z coordinate and measures has four dimensions Syntax ST_CoordDim g ST Geometry Return type INTEGER Example The coorddim_test table is created with the columns geotype and g1 The geotype column stores the name of the geometry subclass stored in the g1 ST_Geometry column CREATE TABLE coorddim_test geotype varchar 20 gl ST_Geometry The INSERT statements insert a sample subclass into the coorddim_test table INSERT INTO coorddim_test VALUES Point ST_PointFromText point 10 02 20 01 1000 s Chapter 8 Spatial functions 8 23 INSERT INTO coorddim_test VALUES Point ST_PointFromText point z 10 02 20 01 3 21 1000 INSERT INTO coorddim_test VALUES LineString ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 s INSERT INTO coorddim_
135. a User s Guide Syntax ST_MPolyFromText WKT lvarchar SRID integer Return type ST_MultiPolygon Example The multipolygon_test table is created with the single ST_MultiPolygon mpl1 column CREATE TABLE multipolygon_test mp11 ST_MultiPolygon The following INSERT statement inserts an ST_MultiPolygon into the mp11 column using the ST_MPolyFromText function INSERT INTO multipolygon_test VALUES ST_MPolyFromText multipolygon 10 01 20 03 10 52 40 11 30 29 41 56 31 78 10 74 10 01 20 03 21 23 15 74 21 34 35 21 28 94 35 35 29 02 16 83 21 23 15 74 40 91 10 92 40 56 20 19 50 01 21 12 51 34 9 81 40 91 10 92 1000 s The ST_MPolyFromWKB function The ST_MPolyFromWKB function takes a well known binary representation of type ST_MultiPolygon and a spatial reference ID to return an ST_MultiPolygon Syntax ST_MPolyFromWKB WKB lvarchar SRID integer Return type ST_MultiPolygon Example The lots table stores the lot_id which uniquely identifies each lot and the lot multipolygon that contains the lot line geometry CREATE TABLE lots lot_id integer lot ST_MultiPolygon This code fragment populates the lots table Create the SQL insert statement to populate the lots table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO lots lot_id lot VALUES ST_MpolyFromWKB d srid Prepare the
136. a and all Java based trademarks are trademarks of Sun Microsystems Inc in the United States other countries or both Linux is a registered trademark of Linus Torvalds in the United States other countries or both Microsoft Windows and Windows NT are trademarks of Microsoft Corporation in the United States other countries or both UNIX is a registered trademark of The Open Group in the United States and other countries Other company product or service names may be trademarks or service marks of others Notices I 3 I 4 IBM Informix Spatial Data User s Guide Index A Abstract data types 1 1 Access methods B tree 4 1 R tree about 4 1 operators for 4 4 Accessibility H 1 dotted decimal format of syntax diagrams H 1 keyboard H 1 shortcut keys H 1 syntax diagrams reading in a screen reader H 1 ADTs 1 1 API 1 2 Application programming interface 1 2 ARC INFO 1 2 ArcSDE 6 3 ArcView 1 2 Big endian D 1 Binary operators 4 5 Bottom up index build 4 3 Boundary 2 2 Bounding box 4 1 C Collection data types sizing 6 1 Collections 2 1 compliance with standards xi Coordinate list C 2 Coordinate systems B 1 Coordinate type C 2 Copy data A 1 D Data types F 1 Datums B 6 B 8 dbf files A 1 DE 9IM_ 7 1 7 16 Dimension 2 3 7 12 7 13 Dimensionally Extended 9 Intersection Model 7 1 7 16 Disabilities visual reading syntax diagrams H 1 Disability H 1 Dotted decimal format of syntax diagrams H 1 E
137. al data is stored in unprojected latitude and longitude format Then when you draw a map you retrieve the data in a particular projection letting the IBM Informix Spatial DataBlade Module do the necessary transformations as it retrieves data from a table First create a spatial_references table entry that is suitable for your unprojected data For this example we use the1983 North American datum Because this is a well known standard datum we can use the SE_CreateSrtext function to create the srtext field INSERT INTO spatial_references srid description falsex falsey xyunits falsez zunits falsem munits srtext VALUES 1004 Unprojected lat lon NAD 83 datum 180 90 5000000 0 1000 0 1000 SE_CreateSrtext 4269 Now create a table and load your data CREATE TABLE airports id char 4 name varchar 128 locn ST_Point INSERT INTO airports VALUES BTM Bert Mooney 1004 point 112 4975 45 9548 INSERT INTO airports VALUES BZN Gallatin Field 1004 point 111 1530 45 7769 INSERT INTO airports VALUES COD Yellowstone Regional 1004 point 109 0238 44 5202 INSERT INTO airports VALUES JAC Jackson Hole 1004 point 110 7377 43 6073 INSERT INTO airports VALUES IDA Fanning Field 1004 point 112 0702 43 5146 Chapter 8 Spatial functions 8 107 Create one or more spatial_references table entries for any projections that you will need Be su
138. alues ST_Point ST_Point ST_LineString ST_LineString 9 ST_MultiPoint ST_MultiPoint ST_Polygon ST_Polygon NA ST_MultiLineString ST_MultiLineString ST_MultiPolygon ST_MultiPolygon SS So Figure 7 1 Equal geometries Copyright IBM Corp 2001 2010 7 1 Related reference The ST_Disjoint function The ST_Disjoint function returns t TRUE if two geometries do not intersect overlap or touch each other ST_Point ST_Point ST_Point ST_MultiPoint ST_Point ST_LineString Point Polygon e J ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_LineString e ST_MultiPoint ST_Polygon ST_LineString ST_Polygon lt gt ST_Polygon ST_Polygon Figure 7 2 Disjoint geometries Related reference The ST_Disjoint function on page 8 30 The ST_Intersects function The ST_Intersects function returns t TRUE if two geometries intersect ST_Intersects returns the opposite result of ST_Disjoint 7 2 IBM Informix Spatial Data User s Guide ST_Point ST_Point ST_Point ST_MultiPoint ST_Point ST_LineString ST_LineString ST_LineString J ST_Point ST_Polygon ST_Point ST_Polygon J ST_MultiPoint ST_Polygon ST_LineString ST_Polygon ST_Polygon ST_Polygon ST_Polygon ST_Polygon Figure 7 3 A selection of geometries that intersect Related reference The ST_Touches function The ST_Touches function returns t TRUE when the interiors of two geometries
139. amming interface API An experienced open database connectivity ODBC programmer can also make calls to the IBM Informix Spatial DataBlade Module SQL functions You can use DB Access to run SQL queries against your spatial data You can also write applications that access the database e ESQL C applications Use the IBM Informix Client Software Development Kit Client SDK Version 2 5 or later to connect to the IBM Informix server e C applications Use the IBM Informix ODBC Driver to connect to the IBM Informix server e Java applications Use the IBM Informix JDBC Driver to connect to the IBM Informix server Querying the spatial columns directly requires converting the data to one of the three supported external formats The ST_AsText function converts a spatial column value to the OGC Well Known Text WKT representation The ST_AsBinary and SE_AsShape functions convert the spatial column values to OGC Well Known Binary WKB and ESRI shape formats Once converted applications can display or manipulate the data You use an R tree index to allow indexing of spatial data R tree indexes are specifically designed to provide fast efficient access to spatial data You can find FAQs examples tips documentation tuning information for using spatial data at http www ibm com software data informix blades spatial Related concepts The spatial_references table on page 1 5 Related reference Work with spatial
140. ample programs are written These examples have not been thoroughly tested under all conditions IBM therefore cannot guarantee or imply reliability serviceability or function of these programs The sample programs are provided AS IS without warranty of any kind IBM shall not be liable for any damages arising out of your use of the sample programs Each copy or any portion of these sample programs or any derivative work must include a copyright notice as follows your company name year Portions of this code are derived from IBM Corp Sample Programs Copyright IBM Corp _enter the year or years_ All rights reserved If you are viewing this information softcopy the photographs and color illustrations may not appear Trademarks IBM the IBM logo and ibm com are trademarks or registered trademarks of International Business Machines Corp registered in many jurisdictions worldwide Other product and service names might be trademarks of IBM or other companies A current list of IBM trademarks is available on the Web at Copyright and trademark information at http www ibm com legal copytrade shtml Adobe the Adobe logo and PostScript are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States and or other countries Intel Itanium and Pentium are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries Jav
141. an replace a variable with an arbitrary name identifier or literal depending on the context Variables are also used to represent complex syntax elements that are expanded in additional syntax diagrams When a variable appears in a syntax diagram an example or text it is shown in lowercase italic The following syntax diagram uses variables to illustrate the general form of a simple SELECT statement p gt SELECT column_name FROM table_name gt lt When you write a SELECT statement of this form you replace the variables column_name and table_name with the name of a specific column and table How to Provide Documentation Feedback xiv You are encouraged to send your comments about IBM Informix user documentation Use one of the following methods e Send email to docinf us ibm com e Go to the information center at http publib boulder ibm com infocenter idshelp v117 index jsp and open the topic that you want to comment on Click the feedback link at the bottom of the page fill out the form and submit your feedback e Add comments to topics directly in the Informix information center and read comments that were added by other users Share information about the product documentation participate in discussions with other users rate topics and IBM Informix Spatial Data User s Guide more Find out more at http publib boulder ibm com infocenter idshel v117 topic com ibm start doc contributing
142. and to ESRI application servers through the IBM Informix ODBC Driver ESRI application servers communicate to license managers and ESRI clients ESRI client R SDE esRI application License applications ESRI client library See SENGT manager Informix ODBC driver ESQL C client applications ii SQL DB Access SQL Informix server C applications Informix ODBC driver Spatial data a R tree index Java applications Informix JDBC driver Figure 1 2 Architecture for IBM Informix and spatial applications IBM Informix Spatial Data User s Guide For each spatial data type there is a text file import and a text file export routine Whenever you execute a load or unload statement in the DB Access utility these import and export routines are automatically called the dbimport and dbexport utilities also use these routines The ESRI ArcSDE service provides immediate access to the spatial data stored in your IBM Informix database for the powerful ESRI GIS software programs ArcView GIS MapObjects and ArcInfo software The ArcSDE service automatically converts spatial column data into ESRI shape representation making it available to all ESRI supported applications and other applications capable of reading this format Accessing spatially enabled tables through the ArcSDE service allows you to write applications using the existing tools offered by ESRI GIS software or create applications using the SDE C application progr
143. ape to retrieve spatial data from the server and send it to a client as in IBM Informix Spatial Data User s Guide SELECT SE_AsShape geomcol FROM mytable IBM Informix automatically casts the output of the SE_AsShape function to the proper data type for transmission to the client You can write user defined routines UDRs in C or SPL to extend the functionality of the existing spatial data type functions You can use SE_AsShape to convert an ST_Geometry to ESRI shapefile format If you pass the output of SE_AsShape to another UDR whose function signature requires an LVARCHAR input you should explicitly cast the return type of SE_AsShape to LVARCHAR as in EXECUTE FUNCTION MySpatialFunc SE_AsShape geomcol lvarchar Syntax SE_AsShape gl ST Geometry Return type ST_Geometry Example The code fragment below illustrates how the SE_AsShape function converts the zone polygons of the sensitive_areas table into shape polygons These shape polygons are passed to the application s draw_polygon function for display Create the SQL expression sprintf sql_stmt SELECT SE_AsShape zone FROM sensitive_areas WHERE SE_EnvelopesIntersect zone SE PolyFromShape d srid Prepare the SQL statement SQLPrepare hstmt UCHAR sql_stmt SQL_NTS Bind the query geometry parameter pcbvaluel query_shape_len SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR
144. arallel queries on page 5 1 Optimize spatial queries You can set environment variables to optimize your spatial queries Running UPDATE STATISTICS HIGH on a very large table might require large amounts of shared memory tens of megabytes If sufficient shared memory is unavailable UPDATE STATISTICS will fail If it fails you can use the ST_MAXLEVELS environment variable to reduce the memory requirements The default value is 16 Decrease it to reduce the amount of memory that is needed to build a histogram Decreasing the value of ST MAXLEVELS might result in a less accurate histogram than would otherwise be possible The minimum recommended value is 12 Set the ST_COSTMULTIPLER environment variable to a non zero positive value to adjust the cost for each row that is computed by the database server The database server multiplies its cost estimate by this value IBM Informix Spatial Data User s Guide If you set either of these environment variables you must stop and restart the database server for the change to take effect To improve performance the database server uses a pool of temporary memory buffers for processing spatial data You can change the behavior of this memory management system if necessary in two ways e By setting the ST MEMMODE environment variable e By changing the value of the MemMode user settable parameter The ST_ MEMMODE environment variable can have three values 0 Disables memory buffer reuse
145. archar 10 zone ST Polygon The program fragment populates the sensitive_areas table Create the SQL insert statement to populate the sensitive_areas table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO sensitive areas id name size type zone VALUES ST PolyFromWKB d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL PARAM INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp id 0 amp pcbvaluel Bind the name to the second parameter pcbvalue2 name_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR 0 0 name 0 amp pcbvalue2 Bind the size to the third parameter pcbvalue3 0 rc SQLBindParameter hstmt 3 SQL PARAM INPUT SQL_C_FLOAT SQL_REAL 0 0 amp size 0 amp pcbvalue3 Bind the type to the fourth parameter pcbvalue4 type_len rc SQLBindParameter hstmt 4 SQL_PARAM_INPUT SQL_C_CHAR SQL_VARCHAR type_len 0 IBM Informix Spatial Data User s Guide type type_len amp pcbvalue4 Bind the zone geometry to the fifth parameter pcbvalue5 zone_wkb_len rc SQLBindParameter hstmt 5 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR zone_wkb_len 0
146. assigned by the ArcSDE service The indexes are three percent greater than the dbspace overhead space and spatial column size of the table To calculate the index space requirements 1 Combine the spatial column size and the dbspace overhead space size 2 Multiply this sum by the number of rows in the table 3 Multiply the result of step 2 by 1 03 Chapter 6 Estimate your spatial data 6 3 6 4 IBM Informix Spatial Data User s Guide Chapter 7 Determine spatial relationships and transform geometries Use specific spatial data type functions to perform operations on spatial data These topics describe spatial data type functions that e Determine spatial relationships e Produce a new geometry e Transform geometries Functions that determine spatial relationships You can use some spatial data type functions to determine whether a specific relationship exists between a pair of geometries The distance separating a hazardous waste disposal site and a school is an example of a spatial relationship The Dimensionally Extended 9 Intersection Model DE 9IM is a mathematical approach that defines the pair wise spatial relationship between geometries of different types and dimensions If you are interested in using this model to understand how the functions in this section operate refer to The ST_Equals function The ST_Equals function returns t TRUE if two geometries of the same type have identical X Y coordinate v
147. at 3 FILE indicates that syntax element FILE repeats Format 3 FILE indicates that syntax element FILE repeats Characters such as commas which are used to separate a string of syntax elements are shown in the syntax just before the items they separate These characters can appear on the same line as each item or on a separate line with the same dotted decimal number as the relevant items The line can also show another symbol that provides information about the syntax elements For example the lines 5 1 5 1 LASTRUN and 5 1 DELETE mean that if you use more than one of the LASTRUN and DELETE syntax elements the elements must be separated by a comma If no separator is given assume that you use a blank to separate each syntax element If a syntax element is preceded by the symbol that element is defined elsewhere The string following the symbol is the name of a syntax fragment rather than a literal For example the line 2 1 0P1 means that you should refer to a separate syntax fragment OP1 The following words and symbols are used next to the dotted decimal numbers Specifies an optional syntax element A dotted decimal number followed by the symbol indicates that all the syntax elements with a corresponding dotted decimal number and any subordinate syntax elements are optional If there is only one syntax element with a dotted decimal number the symbol is displayed on the same line as the syntax element for example
148. ater lakes The ID and name columns of the islands table identifies each island while the land ST_Polygon column stores the island geometry CREATE TABLE islands id integer name varchar 32 land ST Polygon Because interior rings represent the lakes the ST_NumInteriorRing function lists only those islands that have at least one interior ring SELECT name FROM islands WHERE ST_NumInteriorRing land gt 0 The ST_NumPoints function 8 82 The ST_NumPoints function returns the number of points in an ST_Geometry Syntax ST_NumPoints gl ST_Geometry Return type INTEGER Example The numpoints_test table has two columns geotype a VARCHAR column that contains a description of the type of geometry and gl an ST_Geometry type that contains the geometry itself CREATE TABLE numpoints_test geotype varchar 12 gl ST_Geometry The following INSERT statements insert a point a linestring and a polygon INSERT INTO numpoints_test VALUES point ST_PointFromText point 10 02 20 01 1000 J IBM Informix Spatial Data User s Guide INSERT INTO numpoints test VALUES linestring ST_LineFromText linestring 10 02 20 01 23 73 21 92 1000 s INSERT INTO numpoints test VALUES polygon ST_PolyFromText polygon 10 02 20 01 23 73 21 92 24 51 12 98 11 64 13 42 10 02 20 01 1000 s The query lists the geometry type and the number of points in each SELECT geotype ST_NumPoints gl Nu
149. atial functions 8 7 Table 8 1 Spatial functions by task type continued Function task type Description Function name Assist in managing spatial reference systems Computes the false origin and system units for a data set and creates an entry in the spatial_references table The SE_CreateSRID function on page 8 2 Returns the OGC well known text representation of a spatial reference system The SE_CreateSrtext function on page 8 2 Returns a geometry s spatial reference ID The ST_SRID function on page 100 e Returns the Authority Name and Authority SRID of a spatial reference ID Transforms a geometry from one spatial reference system to another The SE_SRID_Authority unction on page 8 101 ERI The ST_Transform function on page 8 10 Administration Returns the in row out of row and total size of a geometry in bytes The SE_InRowSize function on page 8 4 ion The SE_OutOfRowSize unction on page 8 83 En The SE_TotalSize function on page 8 10 Reinitializes the spatial reference system memory cache The SE_Metadatalnit function on page 8 67 Returns the value of a specified parameter or all parameters if called with no parameters The SE_ParamGet function on page 8 8 Sets the specified parameter to a new value The SE_ParamSet function on page 8 8
150. ational efficiency and to allow spatial data type functions to be executed in parallel the contents of the spatial_references table are kept in both a smart large object and a memory cache If these copies become corrupt or unreadable one of the following errors is raised e USE48 SE Metadata lohandle file not found unreadable or corrupt e USE51 SE Metadata smart blob is corrupt or unreadable e USE52 SE Metadata memory cache is locked Execute the SE_MetadataInit function to reinitialize the spatial reference system smart large object and memory cache Syntax SE _MetadataInit Return type The text string OK if the function was successfully executed Example execute function SE MetadataInit Chapter 8 Spatial functions 8 67 Related reference Resolve problems with SE_MetadatalInit on page 5 1 The SE_Midpoint function The SE_Midpoint function determines the midpoint of a linestring The midpoint is defined as that point which is equidistant from both endpoints of a linestring measuring distance along the linestring If the input linestring has Z values or measures the Z value or measure of the midpoint are computed by linear interpolation between the adjacent vertices Syntax SE Midpoint 1n1 ST_LineString Return type ST_Point The ST_MLineFromGML function 8 68 The ST_MLineFromGMLJ function takes a GML2 or GML3 string representation of an ST_MultiLineString and an optional spatial
151. aus_locns VALUES Canberra 1002 point 148 84 35 56 INSERT INTO aus_locns VALUES Melbourne 1002 point 145 01 37 94 INSERT INTO aus_locns VALUES Perth 1002 point 116 04 32 12 INSERT INTO aus_locns VALUES Sydney 1002 point 151 37 33 77 After loading all of your data for the Australian mainland you realize you need to include data for a few outlying islands such as Norfolk Island and the Cocos Islands However the false origin and scale factor that you chose for SRID 1002 will not work for these islands as well IBM Informix Spatial Data User s Guide INSERT INTO aus_locns VALUES Norfolk Is 1002 point 167 83 29 24 USE19 Coordinates out of bounds in ST PointIn INSERT INTO aus_locns VALUES Cocos Is 1002 point 96 52 12 08 USE19 Coordinates out of bounds in ST PointIn The solution is to create a new spatial_references table entry with a false origin and scale factor that accommodates both the old data and new data and then update the old data EXECUTE FUNCTION SE_CreateSrid 95 55 170 10 Australia outer islands lat lon coords expression 1003 INSERT INTO aus_locns VALUES Norfolk Is 1003 point 167 83 29 24 INSERT INTO aus_locns VALUES Cocos Is 1003 point 96 52 12 08 UPDATE aus_locns SET locn ST_Transform locn 1003 ST Point WHERE ST Srid locn 1002 Example 2 Projecting data dynamically In a typical application spati
152. ay not overlap one another or the bounding external ring Polygon rings may only intersect at a single point USE31 Too few points for geometry type in FUNCTION Explanation The number of coordinates entered for the geometry was too few Points and multipoints require a minimum of one point linestrings and multilinestrings require a minimum of two points and polygons and multipolygons require a minimum of four points USE32 Polygon does not close in FUNCTION Explanation The first and last coordinates of a polygon ring must be the same An exterior or interior ring did not close did not have the same first and last coordinates USE33 Interior ring not enclosed by exterior ring in FUNCTION Explanation The interior rings of a polygon must be inside the exterior rings The interior ring was detected to be outside its exterior ring Appendix G Error messages G 3 USE34 USE46 USE34 Polygon has no area in FUNCTION Explanation The rings of a polygon must enclose an area The first and last point of each polygon ring must be the same A ring may not cross itself USE35 Polygon ring contains a spike in FUNCTION Explanation Polygon rings contain spikes whenever coordinates other than the endpoints are the same The boundary of a polygon must be a continuous ring or series of rings USE36 Multipolygon exterior rings overlap in FUNCTION Explanation The exterior rings o
153. between 1000 to 2 1000 The system unit scales the data and cannot be less than one The larger the system unit the greater the scale that can be stored but the smaller the range of values For example given a system unit of 1000 and a false origin of zero data with three digits to the right of the decimal point are supported the range of possible values is reduced to 0 001 to 2 If you want to maintain a scale of three digits to the right of the decimal point set your system units to 1 000 Set the false origin to less than the minimum coordinate value in your data set The false origin must be small enough to account for any buffering of the data If the minimum coordinate value is 10 000 and your application includes functions that buffer the data by 5 000 the false origin must be at least 15 000 Finally make sure that the maximum ordinate value is not greater than 2 by applying the following formula to the maximum value This formula converts floating point coordinates into system units stored value truncate ordinate false origin system unit 0 5 The SE_CreateSRID function on page 8 24 describes the SE_CreateSRID utility function that given the X and Y extents of a spatial data set computes the false origin and system units Restriction Do not change a spatial reference system s false origin and system units after you have inserted spatial data into a table using that SRID These parameters
154. ble which contains two columns gid of type INTEGER which uniquely identifies each row and the g1 column which stores the geometry CREATE TABLE geometry_test gid integer gl ST Geometry The following INSERT statements insert the data into the gid and g1 columns of the geometry_test table The ST_ WKTToSQL function converts the text representation of each geometry into its corresponding IBM Informix Spatial DataBlade Module instantiable subclass INSERT INTO geometry_test VALUES l ST_WKTTOoSQL point 10 02 20 01 j INSERT INTO geometry_test VALUES Zs ST_WKTTOSQL linestring 10 02 20 01 10 01 30 01 10 01 40 01 s INSERT INTO geometry_test VALUES 35 ST_WKTTOSQL polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 INSERT INTO geometry_test VALUES 4 ST_WKTToSQL multipoint 10 02 20 01 10 32 23 98 11 92 35 64 INSERT INTO geometry_test VALUES 55 ST_WKTTOSQL multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 INSERT INTO geometry_test VALUES 6 ST_WKTTOSQL multipolygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 J IBM Informix Spatial Data User s Guide The ST_X function The ST_X function returns the X coordinate of a point Syntax ST_X pt1 ST Point Return type DOUBLE PRECISION Example The x_test table is c
155. ble 1 Little endian MultiPointM The following fields are for a MultiPointM Box The bounding box for the MultiPointM stored in the order Xmin Ymin Xmax Ymax NumParts The number of Points NumPoints An array of Points of length NumPoints M Range The minimum and maximum measures for the MultiPointM stored in the order Mmin Mmax M Array An array of Measures of length NumPoints The following table shows MultiPointM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 28 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumPoints NumPoints Integer 1 Little endian Byte 40 Points Points Point NumPoints Little endian Byte X Mmin Mmin Double 1 Little endian Byte X 8 Mmax Mmax Double 1 Little endian Byte X 16 M Array M Array Double NumPoints Little endian Tip X 40 16 NumPoints PolyLineM A shapefile PolyLineM consists of one or more parts A part is a connected sequence of two or more points Parts may or may not be connected to one another Parts may or may not intersect one another The following fields are for a PolyLineM Box The bounding box for the PolyLineM stored in the order Xmin Ymin Xmax Ymax Appendix E ESRI shape representation E 5 E 6 NumParts The number of parts in the PolyLineM NumPoints The total number of points for all parts Parts An array of length NumParts Stores for each part the index of its first point in
156. ccess to IBM Informix Spatial Data User s Guide SDE client software such as ArcView GIS MapObjects ARC INFO and ArcExplorer MicroStation and AutoCAD are also accessible through SDE CAD client software Related reference Appendix A Load and unload shapefile data on page A 1 Chapter 3 Data exchange formats on page 3 1 Create a spatial index Since spatial columns contain multidimensional geographic data applications querying those columns require an index strategy that quickly identifies all geometries that satisfy a specified spatial relationship For this reason the IBM Informix database server provides support for building a spatial index called the R tree index The two dimensional R tree index differs from the traditional hierarchical one dimensional B tree index Spatial data is two dimensional so you cannot use the B tree index for spatial data Similarly you cannot use an R tree index with non spatial data To create an R tree index on the location column of the hazardous_sites table in our example use the CREATE INDEX statement CREATE INDEX location_ix ON hazardous_sites location ST _Geometry_ops USING RTREE Tip The loadshp utility automatically creates an R tree index for you after loading data The ESRI shp2sde command can also be used to create an R tree index Restriction You cannot rename a database if the database contains a table that has an R tree index defined on it because R tre
157. cede each repetition index_name ijndex_name L table name table_name gt Table Reference gt gt Table Reference gt lt Reference to a syntax segment Table Reference Table Reference Syntax segment view view table table Synonym synonym xii IBM Informix Spatial Data User s Guide How to read a command line syntax diagram Command line syntax diagrams use similar elements to those of other syntax diagrams Some of the elements are listed in the table in Syntax Diagrams Creating a no conversion job gt gt onpladm create job job n d device D database _ gt ae project gt t table gt 1 Setting the Run Mode S server T target Notes 1 See page Z 1 This diagram has a segment named Setting the Run Mode which according to the diagram footnote is on page Z 1 If this was an actual cross reference you would find this segment on the first page of Appendix Z Instead this segment is shown in the following segment diagram Notice that the diagram uses segment start and end components Setting the run mode eae roa d u n N Ba a To see how to construct a command correctly start at the upper left of the main diagram Follow the diagram to the right including the elements that you want The elements in this diagram are
158. cted coordinate system in which the underlying geographic coordinate systems are the same e Between two projected coordinate systems in which the underlying geographic coordinate systems are the same e Between two coordinate systems with the same geographic coordinate system that is a difference in false origin or system unit only USE47 Cannot create SE_Metadata lohandle file NAME Check directory permissions Explanation The metadata lohandle file is created at the time the DataBlade module is registered in your database This file is located in the directory INFORMIXDIR extend spatial versno metadata The user who registers the DataBlade must have write permission on this directory If this error occurs after you have successfully registered the Spatial DataBlade module you should correct the permissions on the metadata directory and then recreate the metadata lohandle file by running the following SQL statement execute function SE MetadatalInit USE48 SE_Metadata lohandle file FILE not found unreadable or corrupt Execute function SE_MetadatalInit to reinitialize Explanation The purpose of the SE_Metadata lohandle file is to allow access to metadata by all parallelized functions of the Spatial DataBlade module It can be restored by running the following SQL statement execute function SE MetadataInit This will reread the spatial_references table recreate a smart large object containing m
159. ction The SE_IsMeasured function returns a 0 for the first row because the point does not have a measure it returns a 1 for the second row because the point does have measures SELECT gid SE_IsMeasured g1 Has_measures FROM measure_test gid has_measures 1 f 2 t The ST_IsRing function The ST_IsRing function takes an ST_LineString and returns t TRUE if it is a ring that is the ST_LineString is closed and simple otherwise it returns f FALSE Properties of geometries are described in Properties of spatial data types on page EL Syntax ST_IsRing 1n1 ST_LineString Return type BOOLEAN Chapter 8 Spatial functions 8 57 Example The ring_linestring table is created with the SMALLINT column gid and the ST_LineString column In1 CREATE TABLE ring_linestring gid smallint In1 ST_LineString The following INSERT statements insert three linestrings into the In1 column The first row contains a linestring that is not closed and is not a ring The second row contains a closed and simple linestring that is a ring The third row contains a linestring that is closed but not simple because it intersects its own interior It is also not a ring INSERT INTO ring_linestring VALUES 1 ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO ring_linestring VALUES 2 ST_LineFromText linestring 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000
160. ction function generates polygons from the intersection of the buffered hazardous waste sites and the sensitive areas The ST_Area function returns the intersection polygons area which is summarized for all hazardous sites by the SUM operator The GROUP BY clause directs the query to aggregate the intersection areas by hazardous waste site ID SELECT hs site_id SUM ST_Area ST_Intersection sa zone ST_Buffer hs location 5 5280 ST_MultiPolygon FROM sensitive_areas sa hazardous sites hs GROUP BY hs site_id site_id sum 102 87000000 00000 59 77158581 63280 In the following figure the circles represent the five mile buffer polygons surrounding the hazardous waste sites The intersection of these buffer polygons with the sensitive area polygons produces three polygons the hospital in the upper left hand corner is intersected twice while the school in the lower right hand corner is intersected only once Nursing Home Figure 8 8 Using the ST_Intersection function Related reference The ST_Intersection function on page 7 7 The ST_Intersects function The ST_Intersects function returns t TRUE if the intersection of two geometries does not result in an empty set otherwise returns f FALSE 8 52 IBM Informix Spatial Data User s Guide Syntax ST_Intersects gl ST_Geometry g2 ST_Geometry Return typ
161. culation EXECUTE FUNCTION SE_CreateSRID 0 0 250000 250000 Springfield county XY coord system expression 5 The return value of the function is the SRID which can then be used when inserting data Related concepts The spatial_references table on page 1 5 The geometry_columns table When you create a table with a spatial column or add a spatial column to an existing table ESRI client software also requires you to add an entry to the geometry_columns table The geometry_columns table is a metadata table like spatial_references that stores data about data IBM Informix Spatial Data User s Guide For the hazardous sites and sensitive areas example the INSERT statements look like this INSERT INTO geometry_columns f_table_catalog f_table_ schema f_table_name f_geometry_column geometry_type srid VALUES mydatabase database name ralph user name sensitive_areas table name zone spatial column name 5 column type 5 polygon 5 srid INSERT INTO geometry_columns f_table_catalog f_table_schema f_table_name f_geometry_column geometry_type srid VALUES mydatabase database name ralph user name hazardous_sites table name location spatial column name i column type 1 point 5 srid Appendix F Values for the geometry_type column on page F 1 shows valid entries for the geometry_type column and the shapes they represent
162. d Specifies a syntax element that can be repeated zero or more times A dotted decimal number followed by the symbol indicates that this syntax element can be used zero or more times that is it is optional and can be repeated For example if you hear the line 5 1 data area you know that you can include more than one data area or you can include none If you hear the lines 3 3 HOST and 3 STATE you know that you can include HOST STATE both together or nothing Notes 1 If a dotted decimal number has an asterisk next to it and there is only one item with that dotted decimal number you can repeat that same item more than once 2 If a dotted decimal number has an asterisk next to it and several items have that dotted decimal number you can use more than one item from the list but you cannot use the items more than once each In the previous example you can write HOST STATE but you cannot write HOST HOST 3 The symbol is equivalent to a loop back line in a railroad syntax diagram Specifies a syntax element that must be included one or more times A dotted decimal number followed by the symbol indicates that this syntax element must be included one or more times For example if you hear the line 6 1 data area you must include at least one data area If you hear the lines 2 2 HOST and 2 STATE you know that you must include HOST STATE or both As for the symbol you can only repeat a particular item if it
163. d argument is the spatial reference identifier to assign to the ST_Geometry For example the SE_GeomFromShape function has the following syntax SE_GeomFromShape shapegeometry SRID The SE_AsShape function converts the geometry value into an ESRI shape representation Related reference Appendix E ESRI shape representation on page E 1 Geography Markup Language representation You can generate a geometry from a Geography Markup Language GML representation The GML can be represented as either GML2 OGC GML standard 2 1 2 or GML3 OGC GML standard 3 1 1 In addition to the two dimensional representation supported by the Open GIS well known binary representation the GML representation also supports optional Z coordinates and measures The following functions generate a geometry from a GML string ST_GeomFromGML The function creates an ST_Geometry from a string of any geometry type ST_PointFromGML The function creates an ST_Point from a point string ST_LineFromGML The function creates an ST_LineString from a polyline string ST_PolyFromShape The function creates an ST_Polygon from a polygon string ST_MPointFromGML The function creates an ST_MultiPoint from a multipoint string ST_MLineFromGML The function creates an ST_MultiLineString from a multipart polyline string ST_MPolyFromGML The function creates an ST_MultiPolygon from a multipart polygon string For all of these functions the
164. dition Version 11 50 is certified under the Common Criteria For more information see Common Criteria Introduction Xi Syntax diagrams Syntax diagrams use special components to describe the syntax for statements and commands Table 2 Syntax Diagram Components Component represented in PDF Component represented in HTML Meaning See sae EE E a see esse Statement begins Se ee eee gt Statement continues on next line ee cS ea E ee ce Statement continues from previous line Poe Oa ee SON DOCS ee gt lt Statement ends SELECT J eben SELECT eveause sce Required item See bee E TENE Foss Optional item LOCAL LOCAL i ALL oe Se Allbevecncs aoe Required item with choice DISTINCT Only one item must be t DISTINCT __ UNIQUE j present UNIQUE ae a a S Jesss Optional items with choice FOR UPDATE FOR UPDATE are shown below the main FOR READ ONLY FOR READ ONLY line one of which you might specify NEXT E a The values below the main G2 bepeee E TE ees oe fass line are optional one of PRIOR PRIQR which you might specify If O PREVIOUS you do not specify an item PREVIOUS the value above the line will be used as the default pataksi eaa Optional items Several items l y are allowed a comma must EEE EE pre
165. ds that touch one another SELECT sl sewer_id s2 sewer_id FROM sewerlines sl sewerlines s2 WHERE ST _Touches sl sewer s2 sewer Related reference The ST_Touches function on page 7 3 The ST_Touches function on page 7 18 The SE_Trace function The SE_Trace function provides tracing for spatial data type functions The SE_Trace function provides the following levels of tracing Level 1 SQL function entry and exit Level 2 Secondary function entry and exit Level 3 Miscellaneous additional tracing Important You should turn off tracing during normal use because it can generate tremendous amounts of trace output data It is intended for use byIBM Software Support in isolating problems Syntax SE_Trace pathname lvarchar level integer Where pathname is a file name and full path on the server machine and level is 1 2 or 3 Return type The text string OK if the function was successfully executed Example This example shows the file separator for UNIX a forward slash If you are using a Windows platform substitute the UNIX file separator with a backslash in the path name execute function SE Trace tmp spatial trc 1 Chapter 8 Spatial functions 8 105 The ST_Transform function 8 106 The ST_Transform function transforms an ST_Geometry into the specified spatial reference system The transformations allowed in the current version of the Spatial DataBlade are
166. e TYPE found in FUNCTION Explanation An unrecognized shapefile type was encountered User response For more information about shapefile types see Shape type values on page E 1 USE10 Unknown or unsupported OpenGIS WKB type TYPE found in FUNCTION Explanation An unrecognized OpenGIS well known binary type was encountered This version of the Spatial DataBlade only supports point linestring USE11 USE22 polygon multipoint multilinestring and multipolygon USE11 Invalid SRID SRID or NULL in FUNCTION Explanation A spatial reference identifier must be an integer value greater than 0 Negative values real numbers and characters are invalid USE12 Unknown or unsupported geometry type TYPE found in FUNCTION Explanation An unrecognized geometry type was encountered If you are inserting spatial data in a binary format it may be corrupt or malformed USE13 Spatial DataBlade not installed correctly the spatial_references table does not exist Explanation The Spatial DataBlade was not able to access the spatial_references table because it could not be found User response Review the installation instructions for the Spatial DataBlade module and if necessary recreate the spatial_references table USE14 Unknown spatial reference identifier SRID Explanation The sde spatial_references table contains a list of all valid spatial reference identi
167. e BOOLEAN Example The fire marshal wants a list of sensitive areas within a five mile radius of a hazardous waste site The sensitive areas are stored in the following sensitive_areas table The zone column is defined as an ST_Polygon type and stores the outline of the sensitive areas CREATE TABLE sensitive_areas id integer name varchar 128 size float type varchar 10 zone ST Polygon The hazardous sites are stored in the hazardous_sites table created with the CREATE TABLE statement that follows The location column defined as an ST_Point type stores the geographic center of each hazardous site CREATE TABLE hazardous sites site_id integer name varchar 40 location ST Point The query returns a list of sensitive area and hazardous site names for sensitive areas that intersect the five mile buffer radius of the hazardous sites SELECT sa name hs name FROM sensitive_areas sa hazardous_sites hs WHERE ST_Intersects ST_Buffer hs location 5 5280 sa zone name Johnson County Hospital name W H Kleenare Chemical Repository name Johnson County Hospital name Landmark Industrial name Summerhill Elementary School name Landmark Industrial Related reference The ST_Intersects function on page 7 2 The ST_Intersects function on page 7 17 The SE_Is3D function The SE_Is3d function returns t TRUE if the ST_Geometry object has three dimensional coordinates otherwise returns f FALSE
168. e because the database server translates and scales each floating point coordinate of the geometry into a 53 bit positive integer prior to storage IBM Informix Spatial Data User s Guide The spatial_references table is pre loaded with an entry for SRID 0 which is suitable for worldwide spatial data in latitude longitude format If SRID 0 is not suitable for your data you can use SE_CreateSRID to assist you in creating a more appropriate spatial_references table entry However because the SE_CreateSRID function only considers the X and Y extents of your data it may not create sufficiently refined parameters to describe the spatial reference system you need For more information about spatial reference systems and how to compute false origins and scale factors review The spatial_references table on paced 1 5 Syntax SE_CreateSrid xmin float ymin float xmax float ymax float description varchar 64 The description parameter is provided to encourage you to document any SRIDs that you create with this function Return type Returns the SRID of a newly created spatial_references table entry as an integer If the spatial_references table already contains an identical entry its SRID is returned Example To create an entry in the spatial_references table that is suitable for spatial data in New Zealand EXECUTE FUNCTION SE_CreateSrid 166 48 180 34 New Zealand lat lon coords expression 1001 The
169. e spatial_references table with the following SQL statement UPDATE spatial_references SET srtext SE _CreateSrtext 4269 WHERE srid 1000 Related reference The SE_CreateSRID function on page 8 24 The text representation of a spatial system on page B 1 The ST_Crosses function 8 26 The ST_Crosses function takes two geometry objects and returns t TRUE if their intersection results in an ST_Geometry object whose dimension is one less than the maximum dimension of the source objects The intersection object must contain points that are interior to both source geometries and the intersection object must not be equal to either of the source objects Otherwise it returns f FALSE Syntax ST_Crosses gl ST Geometry g2 ST Geometry IBM Informix Spatial Data User s Guide Return type BOOLEAN Example The county government is considering a new regulation stating that all hazardous waste storage facilities may not be within five miles of any waterway The county GIS manager has an accurate representation of rivers and streams stored as multilinestrings in the waterways table but has only a single point location for each of the hazardous waste storage facilities CREATE TABLE waterways id integer name varchar 128 water ST_MultiLineString CREATE TABLE hazardous sites site_id integer name varchar 40 location ST Point To determine if it is necessary to alert the county supervisor to any ex
170. e 15 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer NumParts Little endian Byte X Points Points Point NumPoints Little endian Byte Y Zmin Zmin Double 1 Little endian Byte Y 8 Zmax Zmax Double 1 Little endian Byte Y 16 Z Array Z Array Double NumPoints Little endian Byte Z Mmin Mmin Double 1 Little endian Byte Z 8 Mmax Mmax Double 1 Little endian Byte Z 16 M Array M Array Double NumPoints Little endian Tip X 44 4 NumParts Y X 16 NumPoints Z Y 16 8 NumPoints Appendix E ESRI shape representation E 13 E 14 IBM Informix Spatial Data User s Guide Appendix F Values for the geometry_type column The system table geometry_columns maps spatial data types to values in its geometry_type column The following table shows valid entries for the geometry_type column and the shapes they represent Column value Spatial data type ST_Geometry ST_Point ST_Curve ST_LineString ST_Surface ST_Polygon ST_GeomCollection ST_MultiPoint ST_MultiCurve OLOINIDI alr wl NJ ejo ST_MultiLineString Oo ST_MultiSurface ay any ST_MultiPolygon For information about spatial data types see Chapter 2 Spatial data types on Copyright IBM Corp 2001 2010 F 2 IBM Informix Spatial Data User s Guide
171. e ST_StartPoint function returns an empty geometry otherwise the function returns the result as an ST_GeomCollection ST_MultiPoint ST_MultiLineString or ST_MultiPolygon 7 10 IBM Informix Spatial Data User s Guide e e e o ST_Point ST_Point Empty ST_Point ST_Point ST_MultiPoint J o J ST_Point ST_MultiPoint ST_MultiPoint ST_Point ST_MultiPoint ST_MultiPoint J e J e gt J e ST_MultiPoint ST_MultiPoint Empty ST_MultiPoint ST_MultiPoint ST_MultiPoint LAN e A LAN ST_LineString ST_LineString ST_MultiLineString ST_LineString ST_LineString Empty S O FT ST_Polygon ST_Polygon ST_MultiPolygon ST_Polygon ST_Polygon ST_MultiPolygon Figure 7 12 The symmetric difference of geometries Related reference The ST_SymDifference function on page 8 103 The SE_Dissolve function The SE_Dissolve function is an aggregate function that computes the union of geometries of the same dimension if there is just one geometry that satisfies your query it is returned unaltered Chapter 7 Determine spatial relationships and transform geometries 7 11 e e e e o e ST_Point ST_MultiPoint ST_Polygon ST_MultiPolygon Ae e ST_LineString ST_MultiLineString Figure 7 13 Geometries resulting from use of SE_Dissolve Related reference The SE_Dissolve function on page 8 31 Functions that transform geometries 7 12 Some spatial data type functions ge
172. e geometry of the building footprints and the lots The database designer selected multipolygons for both features because lots can be separated by natural features such as a river and building footprints can comprise several buildings CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon CREATE TABLE lots lot_id integer lot ST_MultiPolygon The city engineer first selects the buildings that are not completely contained within one lot SELECT building_id FROM buildingfootprints lots WHERE NOT ST_Contains lot footprint The city engineer realizes that although the first query provides a list of all building IDs that have footprints outside a lot polygon it will not tell if the rest have the correct lot_id assigned to them This second query performs a data integrity check on the lot_id column of the buildingfootprints table SELECT bf building_id bf lot_id lots lot_id FROM buildingfootprints bf lots WHERE NOT ST Contains lot footprint AND lots lot_id lt gt bf lot_id In the following figure the building footprints are labeled with their building IDs and lie inside their lot lines The lot lines are illustrated with dotted lines and although not shown extend to the street centerline to completely encompass the Chapter 8 Spatial functions 8 21 lot lines and the building footprints within them Lot lines l l l i 1208 l Figure 8 3 Building footprin
173. e indexes are implemented with secondary access method Databases that use primary access method also called virtual table interface or secondary access method also called virtual index interface cannot be renamed The query optimizer does not use the R tree index unless the statistics on the table are up to date If the R tree index is created after the data has been loaded the statistics are current and the optimizer will use the index However if the index is created before the data is loaded the optimizer will not use the R tree index because the statistics are out of date To update statistics use the UPDATE STATISTICS SQL statement UPDATE STATISTICS FOR TABLE hazardous_sites Update values in a spatial column The SQL UPDATE statement alters the values in a spatial column just as it does any other type of column Typically spatial column data must be retrieved from the table altered in a client application and then returned to the server The following pair of SQL statements illustrates how to fetch the spatial data from one row in the hazardous_sites table and then update the same item Chapter 1 Getting started with spatial data 1 11 1 12 SELECT ST_AsText location FROM hazardous sites WHERE site_id 102 UPDATE hazardous_sites SET location ST PointFromText point 18000 57000 5 WHERE site_id 102 Perform spatial queries A common task in a GIS application is to retrieve the visible subset of spatia
174. e perimeter of an ST_Polygon or ST_MultiPolygon ST_MultiPoint data type The ST_MultiPoint data type is a collection of ST_Points ST_MultiPoint can define aerial broadcast patterns and incidents of a disease outbreak An ST_MultiPoint is simple if none of its elements occupy the same coordinate space Just like its elements it has a dimension of 0 The boundary of a ST_MultiPoint is NULL ST_MultiLineString data type The ST_MultiLineString data type is a collection of ST_LineStrings ST_MultiLineStrings are used to define streams or road networks Properties ST_MultiLineStrings are simple if they only intersect at the endpoints of the ST_LineString elements ST_MultiLineStrings are nonsimple if the interiors of the ST_LineString elements intersect The boundary of an ST_MultiLineString is the non intersected endpoints of the ST_LineString elements The ST_MultiLineString is closed if all its ST_LineString elements are closed The boundary of a ST_MultiLineString is NULL if all the endpoints of all the elements are intersected In addition to the other properties inherited from the superclass ST_Geometry ST_MultiLineStrings have length The following figure shows examples of ST_MultiLineStrings e 1 is a simple ST_MultiLineString whose boundary is the four endpoints of its two ST_LineString elements e 2 is a simple ST_MultiLineString because only the endpoints of the ST_LineString elements intersect The boundary is two
175. e points array is not significant The following table shows PolygonM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 15 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer NumParts Little endian Byte X Points Points Point NumPoints Little endian Byte Y Mmin Mmin Double 1 Little endian Byte Y 8 Mmax Mmax Double 1 Little endian Byte Y 16 M Array M Array Double NumPoints Little endian Tip X 44 4 NumParts Y X 16 NumPoints Shape types in XYZ space These topics describe shapes with X Y and Z coordinates PointZ A PointZ consists of a triplet of double precision coordinates in the order X Y Z The following table shows PointZ byte stream contents Appendix E ESRI shape representation E 7 E 8 Position Field Value Type Number Byte order Byte 0 Shape Type 9 Integer 1 Little endian Byte 4 X X Double 1 Little endian Byte 12 Y Ne Double 1 Little endian Byte 20 Z Z Double 1 Little endian MultiPointZ A MultiPointZ represents a set of PointZs as follows e The bounding box is stored in the order Xmin Ymin Xmax Ymax e The bounding Z range is stored in the order Zmin Zmax The following table shows MultiPointZ byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 20
176. e st_multipolygon The ST_GeomFromGML function The ST_GeomFromGML function takes a GML2 or GML version 3 string representation and an optional spatial reference ID and returns a geometry object If the srsName attribute is specified in the GML string a corresponding entry must exist in the spatial_references table or it must be specified as UNKNOWN or DEFAULT The GML representation can include Z and M measures but must include the appropriate srsDimension attribute The following table describes the corresponding geometry values for each srsDimension value Table 8 3 Geometry values for srsDimension values srsDimension value Geometry value 2 A geometry value with only X and Y coordinate values 3 A geometry value with X Y and Z coordinate values in GML version 3 or using the lt coordinates gt tag in GML 2 A geometry value with X Y and measure values if the lt X gt lt Y gt and lt M gt tags are used in the lt coord gt elements of the GML representation 4 A geometry value with X Y Z and measure coordinate values Syntax ST_GeomFromGML gml_string lvarchar ST_GeomFromGML gml_string lvarchar SRID integer For SRID specify 2 if the GML conforms to GML version 2 or specify 3 for GML3 The default is 3 Return type ST_Geometry Chapter 8 Spatial functions 8 43 8 44 Example The geometry_test table contains the INTEGER gid column which uniquely identifies each row and t
177. e value is greater than 930 bytes only a pointer of 64 bytes is stored in row This pointer refers to the smart large object in which the actual data is stored Important Store sbspaces on a disk separate from both the table and the indexes To estimate the amount of smart large object storage space 1 Determine the smart large object ratio using the following formula smart large object ratio spatial column size 1920 The smart large object ratio cannot be greater than 1 So if the smart large object ratio you calculate is greater than one set it to 1 2 Multiply your smart large object ratio by the number of rows in your table to obtain the amount of smart large object space used by your table smart large object space smart large object ratio number of rows 3 Determine the amount of in line table space required using the following formula in line space size of spatial table smart large object space Estimating the size of spatial indexes You can calculate the size of your spatial indexes based on the size of your spatial columns and dbspace overhead space size The ArcSDE service creates and maintains two indexes whenever you add a spatial column to one of your tables The ArcSDE service creates an R tree index on the spatial column and a B tree index on the SE_LROW_ID INTEGER column The R tree index is named an_ix1 and the B tree index is named a_n_ix2 where n is the spatial column s layer number
178. e within 100 MB accuracy for large tables to make estimates of greater precision refer to the IBM Informix Performance Guide Further tuning information is available at http www ibm com software data informix blades spatial To estimate the amount of space you need for spatial data add the results of the following calculations Estimating the storage space for the table The total size of a spatial table is equal to the column sizes plus the dbspace overhead size multiplied by the number of rows To make a rough estimate of the storage space required by the spatial table 1 Estimate the number of rows in the table 2 Add the spatial column size the non spatial column size and the dbspace overhead size together 3 Multiply the sum by the estimated number of rows Estimate the size of the spatial column The size of a spatial column depends on the points per feature and coordinate factor and the annotation size Estimate the size of the spatial column using the formula spatial column size average points per feature coordinate factor annotation size The average points per feature is the sum of all coordinate points required to render the features stored in a spatial table divided by the number of rows in the table If the sum of all coordinates is difficult to obtain use the approximations of the average number of points per feature for each data type in the table The collection data types MultiPoin
179. eFromText linestring 10 10 20 20 20 30 10 30 10 20 20 10 1000 s The query returns the results of the ST_IsSimple function The first record returns t because the linestring is simple while the second record returns f because the linestring is not simple SELECT pid ST_IsSimple g1 Is_it_simple FROM issimple_test pid is_it_simple 1 t 2 f The ST_IsValid function The ST_IsValid function takes an ST_Geometry and returns t TRUE if it is topologically correct otherwise it returns f FALSE Properties of geometries are described in Properties of spatial data types on page 2 1 The IBM Informix Spatial DataBlade Module validates spatial data before accepting it so ST_IsValid always returns TRUE This function may be used to validate spatial data supplied by other implementations of the OpenGIS spatial data specification Syntax ST_IsValid g ST Geometry Return type BOOLEAN The ST_Length function The ST_Length function returns the length of an ST_LineString or ST_MultiLineString Chapter 8 Spatial functions 8 59 Syntax ST_Length 1n1 ST_LineString ST_Length miln1 ST_MultiLineString Return type DOUBLE PRECISION Example A local ecologist studying the migratory patterns of the salmon population in the county s waterways wants the length of all stream and river systems within the county The waterways table is created with the ID and name columns that identify each stream and r
180. eString This code fragment populates the sewerlines table with the unique ID class and geometry of each sewer line Create the SQL insert statement to populate the sewerlines table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO sewerlines sewer_id class sewer VALUES SE_LineFromShape d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the sewer_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_SLONG 8 62 IBM Informix Spatial Data User s Guide SQL_INTEGER 0 0 amp sewer_id 0 amp pcbvaluel Bind the sewer_class to the second parameter pcbvalue2 0 rc SQLBindParameter hstmt 2 SQL_PARAM INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp sewer_class 0 amp pcbvalue2 Bind the sewer geometry to the third parameter pcbvalue3 sewer_shape_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C BINARY SQL_INFX_UDT_LVARCHAR sewer_shape_len 0 sewer_shape_ buf sewer_shape_len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The ST_LineFromText function The ST_LineFromText function takes a well known text representation of type ST_LineString and a spatial reference ID and returns an ST_LineString Syntax ST_L
181. e_row_id integer NOT NULL area_id integer name varchar 128 size float type varchar 10 zone ST_Polygon CREATE TABLE hazardous sites se_row_id integer NOT NULL site_id integer name varchar 40 location ST_Point Establish a spatial reference system Before you populate a spatial table you must define a spatial reference system for all of the geometry data that will be loaded into a spatial column Spatial reference system information is stored in the spatial_references table The SRID of a geometry s spatial reference system is stored with the geometry itself so it is important that you choose an SRID carefully If the coordinates of your data are in latitude and longitude you might be able to use one of several predefined SRIDs that are inserted into the spatial_references table If the coordinates are in a different system for example UTM you must define a new spatial reference system Tip If your spatial data is supplied in shapefiles you can use the infoshp utility to help you define a spatial reference system The SE_CreateSRID Q and SE_CreateSrtext SOL functions described in Chapter 8 Spatial functions on page 8 1 can also be helpful For the hazardous sites and sensitive areas example the coordinates are in a local countywide XY coordinate system so we must create a new spatial reference system The X and Y coordinates range from 0 to 250000 The SE_CreateSRID function performs the cal
182. eatened institutions in addition to the zone column which stores the institution ST_Polygon geometries CREATE TABLE sensitive_areas id integer name varchar 128 size float type varchar 10 zone ST Polygon The hazardous_sites table stores the identity of the sites in the site_id and name columns while the actual geographic location of each site is stored in the location point column CREATE TABLE hazardous_sites site_id integer name varchar 40 location ST Point The sensitive_areas and hazardous_sites tables are joined by the ST_Overlaps function which returns t TRUE for all sensitive_areas rows whose zone polygons overlap the buffered five mile radius of the hazardous_sites location points SELECT hs name hazardous_site sa name sensitive_area FROM hazardous_sites hs sensitive_areas sa WHERE ST_Overlaps ST_Buffer hs location 26400 sa zone hazardous site Landmark Industrial sensitive area Johnson County Hospital hazardous site Landmark Industrial sensitive_area Summerhill Elementary School The following figure shows that the hospital and the school overlap the five mile radius of the county s two hazardous waste sites while the nursing home does not IBM Informix Spatial Data User s Guide Hospital na School Nursing Home Figure 8 10 Using the ST_Overlaps function Related reference
183. egal and Intellectual Property Law IBM Japan Ltd 1623 14 Shimotsuruma Yamato shi Kanagawa 242 8502 Japan The following paragraph does not apply to the United Kingdom or any other country where such provisions are inconsistent with local law INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION AS IS WITHOUT WARRANTY OF ANY KIND EITHER EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF NON INFRINGEMENT MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE Some states do not allow disclaimer of express or implied warranties in certain transactions therefore this statement may not apply to you This information could include technical inaccuracies or typographical errors Changes are periodically made to the information herein these changes will be incorporated in new editions of the publication IBM may make improvements and or changes in the product s and or the program s described in this publication at any time without notice Any references in this information to non IBM Web sites are provided for convenience only and do not in any manner serve as an endorsement of those Web sites The materials at those Web sites are not part of the materials for this IBM product and use of those Web sites is at your own risk Copyright IBM Corp 2001 2010 I 1 2 IBM may use or distribute any of the information you supply in any way it believes appropriate without incurring any obligation to you
184. eled with their building ID numbers and displayed alongside their adjacent street 543 1208 Figure 8 1 Building footprints The ST_AsBinary function The ST_AsBinary function takes a geometry object and returns its well known binary representation The return type of ST_AsBinary is defined as ST_Geometry to allow spatial objects greater than 2 kilobytes to be retrieved by a client application Typically you use ST_AsBinary to retrieve spatial data from the server and send it to a client as in SELECT ST_AsBinary geomcol FROM mytable IBM Informix automatically casts the output of the ST_AsBinary function to the proper data type for transmission to the client You can write user defined routines UDRs in C or SPL to extend the functionality of the existing spatial data type functions You can use ST_AsBinary to convert an ST_Geometry to its well known binary representation If you pass the output of Chapter 8 Spatial functions 8 9 ST_AsBinary to another UDR whose function signature requires an LVARCHAR input you should explicitly cast the return type of ST_AsBinary to LVARCHAR as in EXECUTE FUNCTION MySpatialFunc ST_AsBinary geomcol 1varchar Syntax ST_AsBinary gl ST_Geometry Return type ST_Geometry Example The code fragment below converts the footprint multipolygons of the buildingfootprints table into WKB multipolygons using the ST_AsBinary function The multipolygons are passed to the a
185. enerate a geometry from a Takes a GML2 or GML3 string representation of The ST_EnvelopeFromGML GML representation an envelope and returns an ST_Polygon unction on page 8 3 En oN Takes a GML2 or GML3 string representation The ST_GeomFromGML and returns an ST_Geometry unction on page 8 4 Takes a GML2 or GML3 string representation The ST_LineFromGML and returns an ST_LineString unction on page 8 6 Takes a GML2 or GML3 string representation The ST_MLineFromGML and returns an ST_MultiLineString unction on page 8 6 Takes a GML2 or GML3 string representation The ST_MPointFromGML and returns an ST_MultiPoint unction on page 8 7 En Q TR Q TR oo N E y oO WN m lt 5B 2 Prj 8 fo 3 Q lt E Takes a GML2 or GML3 string representation and returns an ST_MultiPolygon En eN unction on page 8 7 E gt oO WN hee O 5 Prj 8 lo 5 A lt B Takes a GML2 or GML3 string representation and returns an ST_Point ER oo unction on page 8 8 E g oO ioe m a lgs 8 e 3 O lt 2 Takes a GML2 or GML3 string representation and returns an ST_Polygon function on page 8 93 Generate a geometry from a Takes a KML LatLonBox string representation The SE_EnvelopeFromKML KML representation and returns an ST_Polygon function on page 8 36 Takes a KML fragment string representation The ST_GeomFromKML and
186. ep using a non English locale but you must use dots in all text input as follows ST_PointFromText point zm 10 01 20 04 3 2 9 5 1 This is true even if in your locale you normally use 3 2 instead of 3 2 External text always contains dots regardless of the locale Spatial data types with SPL You can use stored procedure language SPL with spatial data types SPL has two restrictions that might be relevant to working with spatial data e LVARCHAR variables in an SPL routine are restricted to 2K e SPL does not support a global variable defined on a UDT or complex type Chapter 2 Spatial data types 2 9 2 10 IBM Informix Spatial Data User s Guide Chapter 3 Data exchange formats You can use several different GIS data exchange formats for spatial data Related concepts Overview of using spatial data on page 1 2 Related reference Insert data into a spatial column on page 1 9 Well known text representation You can generate a geometry from the OGC well known text WKT representation The WKT is an ASCII text formatted string that allows geometry to be exchanged in ASCII text form You can use the following functions in a third or fourth generation language 3GL or 4GL program because they do not require the definition of any special program structures ST_GeomFromText The function creates an ST_Geometry from a text representation of any geometry type ST_PointFromText The function create
187. er locales in your data or your SQL identifiers or if you want to conform to other collation rules for character data For instructions about how to specify locales additional syntax and other considerations related to GLS locales see the IBM Informix GLS User s Guide What s new in spatial data for IBM Informix Version 11 70 This publication includes information about new features and changes in existing functionality The following changes and enhancements are relevant to this publication For a complete list of what s new in this release see the release notes or the information center at http publib boulder ibm com infocenter idshelp v117 topic com ibm po doc new_features htm Table 1 What s new for the IBM Informix Spatial Data User s Guide for Version 11 70 xC1 Overview Reference Spatial data type and functions are built in and automatically registered You can use the data types and functions of the spatial extension which was formerly known as the Spatial DataBlade module without performing some of the previously required prerequisites tasks such as installing or registering the spatial extension The sbspace to store spatial data and statistics information is also created automatically if the SBSPACENAME and SYSSBSPACENAME configuration parameter are not already set New editions and product names For more information about the Informix go tolhttp www ibm com software data in
188. erprets the altitude specification in the geometry and places it at that altitude above the ground absolute Interprets the altitude specification in the geometry and places it at that altitude above sea level The Spatial DataBlade module does not check whether the attributes are valid If any of the attributes are not valid the resulting KML fragment might not be valid when it is received by the application Return type LVARCHAR Example EXECUTE FUNCTION ST_AsKML ST_PointFromText POINT 83 54354 34 23425 4 Output lt Point gt lt coordinates gt 83 5435399663 34 2342500677 lt coordinates gt lt Point gt In this example ST_ASKML contains KML shape attributes to specify that the geometry is connected to the ground EXECUTE FUNCTION ST_AsKML ST_PointFromText POINT Z 83 54523 34 214312 100 4 lt extrude gt 1 lt extrude gt lt al ti tudeMode gt clampToGround lt altitudeMode gt Output lt Point gt lt extrude gt 1 lt extrude gt lt altitudeMode gt clampToGround lt altitudeMode gt lt coordinates gt 83 545522957 34 2143120335 100 lt coordinates gt lt Point gt The SE_AsShape function 8 14 The SE_AsShape function takes a geometry object and returns it in ESRI shapefile format The return type of SE_AsShape is defined as ST_Geometry to allow spatial objects greater than 2 kilobytes in size to be retrieved by a client application Typically you use ST_AsSh
189. es After you have created an index it is considered by the query optimizer for any supported combination of argument types The index can be used regardless of whether the indexed column is the first or second argument An operator with two parameters also known as a binary operator can take advantage of an index defined on a column that serves as one of its arguments Chapter 4 R tree indexes 4 5 4 6 IBM Informix Spatial Data User s Guide Chapter 5 Run parallel queries Running queries in parallel distributes the work for one aspect of a query among several processors and can dramatically improve performance You can use any of the spatial data type functions in a parallel query except the SE_BoundingBox SE_CreateSRID SE_MetadataInit and SE_Trace functions Related reference Perform spatial queries on page 1 12 Parallel query execution infrastructure The database server creates and maintains various database objects to manage the execution of spatial queries in parallel Do not alter or delete any of the following items of infrastructure e The SE_MetadataTable table e The SE_Metadata opaque type e The metadata smart large object which is stored in the default sbspace e The metadata lohandle file e The metadata memory cache e Triggers on the spatial_references table You can use the SE_MetadataInit function to re initialize this infrastructure in case of difficulty Resolve
190. escription of R tree indexes refer to the IBM Informix R Tree Index User s Guide Syntax for creating an R tree index To use the R tree access method you create an index on a column of a spatial type Syntax gt gt CREATE INDEX index_name ON table_name gt Copyright IBM Corp 2001 2010 4 1 gt column_name ST_Geometry_Ops gt USING RTREE gt lt Liame index_opt jones Element Description column_name The name of the spatial column index_name The name to give your index index_options The index options are FRAGMENT BY and IN parameters The parameters available for R tree indexes are bottom_up_build BOUNDING_BOX_INDEX NO_SORT sort_memory and fill_factor table_name The name of the table that contains the spatial column to index Restriction You cannot rename databases that contain R tree indexes The BOTTOM_UP_BUILD BOUNDING_BOX_INDEX and NO_SORT parameters affect the size of the index and the speed at which it is built The following table shows the valid combinations of these parameters Table 4 1 Parameters of the CREATE INDEX statement for spatial data Parameters clause of CREATE INDEX statement Description BOTTOM_UP_BUILD no BOUNDING_BOX_INDEX no NO_SORT no Creates an index by inserting spatial objects into the R tree one at a time A copy of each object s in row data is sto
191. est_multipoly table is created with the INTEGER column id and the ST_MultiPolygon column geom CREATE TABLE test_multipoly id INTEGER geom ST_MultiPolygon INSERT INTO test_multipoly VALUES 1 ST_MPolyFromKML lt MultiGeometry gt lt Pol ygon gt lt outerBoundaryIs gt lt LinearRing gt lt coordinates gt 94 36 32 49 92 65 32 68 92 15 32 46 93 09 33 08 93 37 33 18 94 36 32 49 lt coordinates gt lt LinearRing gt lt outerBoundaryIs gt lt Pol ygon gt lt Pol ygon gt lt outerBoundaryIs gt lt LinearRing gt lt coordinates gt 84 36 32 49 82 65 32 68 82 15 32 46 83 09 33 08 83 37 33 18 84 3600000805 32 4900000536 lt coordinates gt lt LinearRing gt lt outerBoundaryIs gt lt Pol ygon gt lt MultiGeometry gt 4 This record specifies a spatial reference ID of 4 WGS84 and both member polygons have two dimensions and six sides Output Chapter 8 Spatial functions 8 77 SELECT FROM test_multipoly id 1 geom 4 MULTIPOLYGON 94 3600000805 32 4900000536 92 6599999799 326899999866 92 1500000335 32 4600000469 93 0900000201 33 0800000738 93 3700000268 33 1899999866 94 3600000805 324900000536 84 3600000805 32 4900000536 82 6599999799 326899999866 82 1500000335 32 4600000469 83 0900000201 33 0800000738 83 3700000268 33 1899999866 84 3600000805 32 4900000536 The SE_MPolyFromShape function The SE_MPolyFromShape function takes a shape of type polygon and a spatial
192. etadata and re create a file containing the large object handle for this smart large object USE49 SE_MetadataTable is a read only table Explanation The SE_MetadataTable table is created and populated when the Spatial DataBlade module is registered User response Do not attempt to modify this table in any way USE50 Vertex not found in FUNCTION Explanation The specified vertex cannot be found in the original geometry User response Verify that the X Y M and Z values if any of the vertex to be updated or deleted exactly match USE51 SE_Metadata smart blob is corrupt or unreadable Explanation Execute the SE_MetadataInit function to repair the smart large object To enable parallel data queries a copy of the spatial_references table contents is stored in a smart large object This smart large object is created when the Spatial DataBlade is registered and is synchronized with the spatial_references table by USE47 674 means of triggers If the smart large object is corrupted it can be re created by running the following SQL statement EXECUTE FUNCTION SE MetadataInit USE52 SE_Metadata memory cache is locked Explanation Execute the SE_MetadataInit function to reinitialize the memory cache For computational efficiency a copy of the spatial_references table contents is cached in memory This cache is shared by all sessions and access to it is controlled by a spinlock If a sess
193. eter pcbvalue5 zone_shape_len rc SQLBindParameter hstmt 5 SQL_PARAM_INPUT SQL_C BINARY SQL_INFX_UDT_LVARCHAR zone_shape_len 0 zone_shape_buf zone _shape_len amp pcbvalued Execute the insert statement rc SQLExecute hstmt The ST_PolyFromText function The ST_PolyFromText function takes a well known text representation of type ST_Polygon and a spatial reference ID and returns an ST_Polygon Syntax ST_PolyFromText wkt lvarchar SRID integer Return type ST_Polygon Example The polygon_test table is created with the single polygon column CREATE TABLE polygon_test pl1 ST Polygon The following INSERT statement inserts a polygon into the pl1 polygon column using the ST_PolyFromText function Chapter 8 Spatial functions 8 95 INSERT INTO polygon_test VALUES ST_PolyFromText polygon 10 01 20 03 10 52 40 11 30 29 41 56 31 78 10 74 10 01 20 03 1000 J The ST_PolyFromWKB function 8 96 The ST_PolyFromWKB function takes a well known binary representation of type ST_Polygon and a spatial reference ID to return an ST_Polygon Syntax ST_PolyFromWKB wkb lvarchar SRID integer Return type ST_Polygon Example The sensitive_areas table contains several columns that describe the threatened institutions in addition to the zone column which stores the institution ST_Polygon geometries CREATE TABLE sensitive_areas id integer name varchar 128 size float type v
194. ether or always absent together the elements can appear on the same line because they can be considered as a single compound syntax element Each line starts with a dotted decimal number for example 3 or 3 1 or 3 1 1 To hear these numbers correctly make sure that your screen reader is set to read punctuation All syntax elements that have the same dotted decimal number for example all syntax elements that have the number 3 1 are mutually exclusive Copyright IBM Corp 2001 2010 H 1 H 2 alternatives If you hear the lines 3 1 USERID and 3 1 SYSTEMID your syntax can include either USERID or SYSTEMID but not both The dotted decimal numbering level denotes the level of nesting For example if a syntax element with dotted decimal number 3 is followed by a series of syntax elements with dotted decimal number 3 1 all the syntax elements numbered 3 1 are subordinate to the syntax element numbered 3 Certain words and symbols are used next to the dotted decimal numbers to add information about the syntax elements Occasionally these words and symbols might occur at the beginning of the element itself For ease of identification if the word or symbol is a part of the syntax element the word or symbol is preceded by the backslash character The symbol can be used next to a dotted decimal number to indicate that the syntax element repeats For example syntax element FILE with dotted decimal number 3 is read as 3 FILE Form
195. etry and Polygon combination string ST_PointFromKML The function creates an ST_Point from a KML Point string ST_PolyFromKML The function creates an ST_Polygon from a KML Polygon string For most of these functions the first argument is the KML representation and the second optional argument is the spatial reference identifier to assign to the ST_Geometry For example the ST_LineFromKMLJ function has the following syntax ST_LineFromKML kmlstring lvarchar SRID integer The SE_AsKML and ST_AsKMLJ functions convert the geometry value into a GML representation The ST_EnvelopeAsKMLJ function converts an ST_Envelope bounding box into a KML LatLonBox string IBM Informix Spatial Data User s Guide Chapter 4 R tree indexes An index organizes access to data so that entries can be found quickly without searching every row The R tree access method enables you to index multidimensional objects Queries that use an index execute more quickly and provide a significant performance improvement The R tree access method speeds access to multidimensional data It organizes data in a tree shaped structure with bounding boxes at the nodes Bounding boxes indicate the farthest extent of the data that is connected to the subtree below A search using an R tree index can quickly descend the tree to find objects in the general area of interest and then perform more exact tests on the objects themselves An R tree index can impro
196. eturns TRUE when the interiors of the geometry do not intersect and the boundary of either geometry intersects the other s interior or boundary The ST_Touches function returns TRUE if the boundary of one geometry intersects the interior of the other but the interiors do not intersect b Interior Boundary Exterior Interior F T 7 18 IBM Informix Spatial Data User s Guide b Interior Boundary Exterior a Boundary 7 Exterior i j The ST_Touches function returns TRUE if the boundary of one geometry intersects the interior of the other but the interiors do not intersect b Interior Boundary Exterior Interior F j a Boundary j Exterior 5 i The ST_Touches function returns TRUE if the boundaries of both geometries intersect but the interiors do not b Interior Boundary Exterior Interior F j a Boundary s T 4 Exterior i Related reference The ST_Overlaps function The ST_Operlaps function returns TRUE if the intersection of the objects results in an object of the same dimension but not equal to either source object This pattern matrix applies to ST_Polygon and ST_Polygon ST_MultiPoint and ST_MultiPoint and ST_MultiPolygon and ST_MultiPolygon overlaps For these combinations the ST_Overlaps function returns TRUE if the interior of both geometries intersects the other s interior and exterior b Interior Boundary Exterior Interior T a T
197. ewer_id class sewer VALUES ST_LineFromWKB d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the sewer_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL PARAM INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp sewer_id 0 amp pcbvaluel Bind the sewer_class to the second parameter pcbvalue2 0 rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL _C_SLONG SQL_INTEGER 0 0 amp sewer_class 0 amp pcbvaluez2 Bind the sewer geometry to the third parameter pcbvalue3 sewer_wkb_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR sewer_wkb_len 0 sewer_wkb buf sewer_wkb_len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The SE_LocateAlong function 8 64 The SE_LocateAlong function takes a geometry object and a measure to return as an ST_MultiPoint the set of points found having that measure Syntax SE_LocateAlong gl ST Geometry ml double precision Return type ST_Geometry Example The locatealong_test table is created with two columns the gid column uniquely identifies each row and the g1 ST_Geometry column stores sample geometry IBM Informix Spatial Data User s Guide CREATE TABLE locatealong test gid integer gl ST Geometry The following INSERT statements insert two rows The first is a
198. ex and returns the nth ST_Geometry object in the collection Syntax ST_GeometryN mptl ST_MultiPoint index integer ST_GeometryN mIn1 ST_MultiLineString index integer ST_GeometryN mpl1 ST_MultiPolygon index integer Return type ST_Geometry Example The city engineer wants to know which building footprints are all inside the first polygon of the lots ST_MultiPolygon The building_id column uniquely identifies each row of the buildingfootprints table The lot_id column identifies the building s lot The footprint column stores the building geometries CREATE TABLE buildingfootprints building id integer lot_id integer footprint ST_MultiPolygon CREATE TABLE lots lot_id integer lot ST_MultiPolygon Chapter 8 Spatial functions 8 41 The query lists the buildingfootprints table values of building_id and lot_id for all building footprints that are all within the first lot polygon The ST_GeometryN function returns a first lot polygon element in the ST_MultiPolygon SELECT bf building_id bf lot_id FROM buildingfootprints bf lots WHERE ST Within footprint ST GeometryN lot 1 AND bf lot_id lots lot_id The ST_GeometryType function 8 42 The ST_GeometryType function takes an ST_Geometry object and returns its geometry type as a string Syntax ST_GeometryType gl ST Geometry Return type VARCHAR 32 containing one of the following text strings e st_point st_linestring e st_polygon e st_mul
199. f a multipolygon must enclose independent areas The exterior rings of each polygon of a multipolygon may not overlap They may however intersect at a single point Polygons whose intersection results in a linestring will automatically be merged after the intersecting linestring has been dissolved USE37 The geometry boundary is self intersecting in FUNCTION USE38 The geometry has too many parts in FUNCTION Explanation The string that defines the geometry has too many parts for its type Points linestrings and polygons are single part geometries The string has defined more than one part for one of these geometries If a multipart geometry is desired use multipoint multilinestring or multipolygon USE39 Mismatched text string parentheses in FUNCTION Explanation The parentheses of the text string defining the geometry do not match User response For a description of the well known text representation review Appendix C OGC well known text representation of geometry on page Unknown or unsupported ESRI entity type TYPE found in FUNCTION Explanation The internal type representation is invalid User response Contact ESRI Technical Support G 4 IBM Informix Spatial Data User s Guide USE41 The projection string for your SRID is invalid in FUNCTION Explanation The projection string stored in the spatial_references table was determined to be invalid User res
200. f this format UNIT Degree 0 0174532925199433 The following example shows how to insert a spatial reference system into the spatial_references table INSERT INTO spatial_references srid description auth_name auth_srid falsex falsey xyunits falsez zunits falsem munits srtext VALUES 1 NULL NULL NULL 0 0 100 0 1 0 1 UNKNOWN In this example the spatial reference system has an SRID value of 1 a false X Y of 0 0 and its system units are 100 The Z coordinate and measure offsets are 0 while the Z coordinate and measure units are 1 The next topics describe how to choose appropriate values for the falsex falsey falsez falsem xyunits zunits and munits columns Select a false origin and system units Select a false origin and system unit to store all of your coordinate values at an acceptable scale To do so you must know the range of your data and the scale to maintain Because coordinates are stored as positive 54 bit integers the maximum 1 6 IBM Informix Spatial Data User s Guide range of values allowed is between 0 and 9 007 199 254 740 991 but the actual range is dependent on the false origin and system units of the spatial reference system A negative false origin shifts the range of values in the negative direction A positive false origin shifts the range of values in the positive direction For example a false origin of 1000 with a system unit of one stores a range of values
201. face each island shares with the sea Some of the islands have lakes which are represented by the interior rings of the polygons Chapter 8 Spatial functions 8 49 8 50 Island shoreline Figure 8 7 Islands and lakes The ID and name columns of the islands table identifies each island while the land ST_Polygon column stores the island geometry CREATE TABLE islands id integer name varchar 32 land ST_Polygon This ODBC code fragment uses the ST_InteriorRingN function to extract the interior ring lake from each island polygon as a linestring The perimeter of the linestring returned by the ST_Length function is totaled and displayed along with the island ID Prepare and execute the query to get the island IDs and number of lakes interior rings sprintf sql_stmt SELECT id ST_NumInteriorRing land FROM islands Allocate memory for the island cursor rc SQLAllocHandle SQL_HANDLE_STMT hdbc amp island_cursor rc SQLExecDirect island_cursor UCHAR sql_stmt SQL_NTS Bind the island table s id column to island_id rc SQLBindCol island_cursor 1 SQL_C_SLONG amp island_id 0 amp id_ind Bind the result of ST NumInteriorRing land to num_lakes rc SQLBindCol island_cursor 2 SQL_C_SLONG amp num_lakes 0 amp lake_ind Allocate memory to the SQL statement handle lake_cursor rc SQLAllocHandle SQL_HANDLE_STMT hdbc amp lake cursor Prepa
202. fiers The function attempted to create a geometry with an SRID that does not exist in this table User response Either use an SRID that is already in the sde spatial_references table or add the unknown SRID to the table USE15 Invalid coordinate reference system object in function FUNCTION Explanation A programmatic error has occurred in the Spatial DataBlade User response Contact IBM Informix Technical Support USE16 Unable to get the geometry data pointer from the server in FUNCTION Explanation A programmatic error has occurred in the Spatial DataBlade User response Contact IBM Informix Technical Support G 2 IBM Informix Spatial Data User s Guide USE17 Geometry verification failed Explanation An error has occurred while the Spatial DataBlade was verifying the topological correctness of a geometry User response Contact IBM Informix Technical Support USE18 Buffer operation failed Explanation The source geometry and buffer distance submitted to the buffer function would result in a buffer with coordinates that fall outside the coordinate system specified in the source geometry s spatial reference system USE19 Coordinates out of bounds in FUNCTION Explanation The function has created a geometry with coordinates that fall outside the coordinate system User response Review The spatial_references table on page 1 5 for information about selecting a coordinate
203. formix IBM Informix Dynamic Server editions were withdrawn and new Informix editions are available Some products were also renamed The publications in the Informix library pertain to the following products e IBM Informix database server formerly known as IBM Informix Dynamic Server IDS e IBM OpenAdmin Tool OAT for Informix formerly known as OpenAdmin Tool for Informix Dynamic Server IDS e IBM Informix SQL Warehousing Tool formerly known as Informix Warehouse Feature Example code conventions x Examples of SQL code occur throughout this publication Except as noted the code is not specific to any single IBM Informix application development tool IBM Informix Spatial Data User s Guide If only SQL statements are listed in the example they are not delimited by semicolons For instance you might see the code in the following example CONNECT TO stores_demo DELETE FROM customer WHERE customer_num 121 COMMIT WORK DISCONNECT CURRENT To use this SQL code for a specific product you must apply the syntax rules for that product For example if you are using an SQL API you must use EXEC SQL at the start of each statement and a semicolon or other appropriate delimiter at the end of the statement If you are using DB Access you must delimit multiple statements with semicolons Tip Ellipsis points in a code example indicate that more code would be added in a full application but it is not nece
204. function The SE_MLineFromShape function The ST_MLineFromText function The ST_MLineFromWKB function The SE_Mmax and SE_Mmin functions The ST_MPointFromGML function The ST_MPointFromKML function The SE_MPointFromShape function The ST_MPointFromText function The ST_MPointFromWKB function The ST_MPolyFromGML function The ST_MPolyFromKML function The SE_MPolyFromShape function The ST_MPolyFromText function The ST_MPolyFromWKB function The SE_Nearest and SE_NearestBbox furictions The ST_NumGeometries function The ST_NumInteriorRing function The ST_NumPoints function The SE_OutOfRowSize function The ST_Overlaps function The SE_ParamGet function The SE_ParamSet function The ST_Perimeter function 2 The SE_PerpendicularPoint function The ST_Point function The ST_PointFromGML function The ST_PointFromKML function The SE_PointFromShape function The ST_PointFromText function The ST_PointFromWKB function The ST_PointN function The ST_PointOnSurface function The ST_PolyFromGML function The ST_PolyFromKML function The SE_PolyFromShape function The ST_PolyFromText function The ST_PolyFromWKB function The ST_Polygon function The ST_Relate function The SE_Release function The SE_ShapeToSQL function The SE_SpatialKey function The ST_SRID function es The SE_SRID_Authority function The ST_StartPoi
205. g spatial data Preparing to use spatial data Sbspaces for spatial data The spatial_references table The structure of the spatial_ references table Select a false origin and system units Work with spatial tables Create a spatial table Insert data into a spatial column Create a spatial index Update values in a spatial column Perform spatial queries Optimize spatial queries Spatial data replication The IBM Informix Web Feature Service Chapter 2 Spatial data types Properties of spatial data types Interior boundary and exterior Simple or nonsimple Empty or not empty Number of points Envelope Dimension Z coordinates Measures Spatial reference system ST_Point data type ST_LineString data type ST_Polygon data type ST_MultiPoint data type ST_MultiLineString data type ST_MultiPolygon data type Locale override Spatial data types with SPL Chapter 3 Data exchange formats Well known text representation Well known binary representation Copyright IBM Corp 2001 2010 ix ix ix xi Xi xii xiii Xiv Xiv Xiv 15 1 7 1 11 1 11 1 12 1 12 1 13 1 14 2 2 2 3 2 4 2 7 3 1 ESRI shape representation Geography Markup Language representation Keyhole Markup Language representation Chapter 4 R tree indexes Syntax for creating an R tree index Bottom up versus top down index builds Functional R tree indexes Ve
206. he ST_Contains function on page 8 21 Chapter 7 Determine spatial relationships and transform geometries 7 21 7 22 IBM Informix Spatial Data User s Guide Chapter 8 Spatial functions These topics provide reference information for the spatial data type functions All OpenGIS ISO SQLMM compliant functions have the prefix ST_ while functions that extend the OpenGIS ISO SQLMM specification have the prefix SE_ Summary of spatial functions by task type The spatial data type functions perform different types of tasks such as generating different formats manipulating or comparing data and obtaining information about data The following table shows the spatial data type functions arranged by task type Table 8 1 Spatial functions by task type Function task type Description Function name Generate a geometry from a well known text representation Takes a well known text representation and returns an ST_Geometry using SRID 0 The ST_WKTToSQL function on page 8 112 Takes a well known text representation and returns an ST_Geometry The ST_GeomFromText unction on page 8 47 p Takes a well known text representation and returns an ST_Point The ST_PointFromText unction on page 8 90 p Takes a well known text representation and returns an ST_LineString The ST_LineFromText function on page 8 6 Takes a well known text representation and returns a
207. he Z values for part 2 follow the Z values for part 1 and so on The parts array holds the array index of the starting point for each part There is no delimiter in the Z Array between parts The following table shows PolyLineZ byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 10 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer NumParts Little endian Byte X Points Points Point NumPoints Little endian Byte Y Zmin Zmin Double 1 Little endian Byte Y 8 Zmax Zmax Double 1 Little endian Byte Y 16 Z Array Z Array Double NumPoints Little endian Tip X 44 4 NumParts Y X 16 NumPoints PolygonZ A PolygonZ consists of a number of rings A ring is a closed non self intersecting loop A PolygonZ may contain multiple outer rings The rings of a PolygonZ are referred to as its parts The following fields are for a PolygonZ Box The bounding box for the PolygonZ stored in the order Xmin Ymin Xmax Ymax NumParts The number of rings in the PolygonZ NumPoints The total number of points for all rings Parts An array of length NumParts Stores for each ring the index of its first point in the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each ring in the PolygonZ are stored end
208. he g1 column which stores the geometry CREATE TABLE geometry_test gid smallint gl ST Geometry The following INSERT statements insert the data into the gid and g1 columns of the geometry_test table The ST_GeomFromGML function converts the GML text representation of each geometry into its corresponding instantiable subclass INSERT INTO geometry_test VALUES l ST_GeomFromGML lt gm Point srsName DEFAULT srsDimension 2 gt lt gml pos gt 10 02 20 01 lt gml pos gt lt gml Point gt 1000 INSERT INTO geometry_test VALUES 2 ST_GeomFromGML lt gml LineString srsName DEFAULT srsDimension 2 gt lt gml posList dimension 2 gt 10 01 20 01 10 01 30 01 10 01 40 01 lt gml posList gt lt gml LineString gt 1000 INSERT INTO geometry_test VALUES 35 ST_GeomFromGML lt gm1 Polygon srsName DEFAULT srsDimension 2 gt lt gml exterior gt lt gm LinearRing gt lt gml posList dimension 2 gt 10 02 20 01 19 15 33 94 25 02 34 15 11 92 35 64 10 02 20 01 lt gml posList gt lt gml LinearRing gt lt gml exterior gt lt gm1 Polygon gt 1000 INSERT INTO geometry_test VALUES 4 ST_GeomFromGML lt gm MultiPoint srsName DEFAULT srsDimension 2 gt lt gm PointMember gt lt gml Point srsName DEFAULT srsDimension 2 gt lt gml pos gt 10 02 20 01 lt gm1 pos gt lt gml Point gt lt gml PointMember gt lt gml PointMember gt lt gml Point srsName DEFAULT srsDimension
209. her_Modified 6378155 298 3 106208 Ayabelle Lighthouse DATUM D_Ayabelle SPHEROID Clarke_1880_RGS 6378249 145 293 465 106211 Point 58 DATUM D_Point_58 SPHEROID Clarke_1880_RGS 6378249 145 293 465 106212 Astro Beacon E 1945 DATUM D_Beacon_E_1945 SPHEROID International_1924 6378388 297 106213 Tern Island Astro DATUM D_Tern_Island_1961 SPHEROID International_1924 6378388 297 1961 106214 Astronomical Station DATUM D_Astro_1952 SPHEROID International_1924 6378388 297 1952 106215 Bellevue IGN DATUM D_Bellevue_IGN SPHEROID International_1924 6378388 297 106216 Canton Astro 1966 DATUM D_Canton_1966 SPHEROID International_1924 6378388 297 106217 Chatham Island DATUM D_Chatham_Island_1971 SPHEROID International_1924 Astro 1971 6378388 297 106218 DOS 1968 DATUM D_DOS_1968 SPHEROID International_1924 6378388 297 106219 Easter Island 1967 DATUM D_Easter_Island_1967 SPHEROID International_1924 6378388 297 106220 Guam 1963 DATUM D_Guam_1963 SPHEROID Clarke_1866 6378206 4 294 9786982 106221 GUX 1 Astro DATUM D_GUX_1 SPHEROID International_1924 6378388 297 106222 Johnston Island 1961 DATUM D_Johnston_Island_1961 SPHEROID International_1924 6378388 297 106259 Kusaie Astro 1951 DATUM D_Kusaie_1951 SPHEROID International_1924 6378388 297 106224 Midway Astro 1961 DATUM D_Midway_1961 SPHEROID International_1924 6378388 297 106226 Pitcairn Astro 1967 DATUM D_Pitcairn_19
210. hile the actual geographic location of each site is stored in the location point column CREATE TABLE hazardous_sites site_id integer name varchar 40 location ST_Point The ST_Buffer function generates a five mile buffer surrounding the hazardous waste site locations The ST_Union function generates polygons from the union of the buffered hazardous waste site polygons and the sensitive areas The ST_Area function returns the unioned polygon area SELECT sa name sensitive_area hs name hazardous_site ST_Area ST_Union ST_Buffer hs location 5 5280 sa zone ST_MultiPolygon area FROM hazardous_sites hs sensitive_areas sa See also The SE_Dissolve function on page 8 31 Related reference The ST_Union function on page 7 9 The SE_VertexAppend function The SE_VertexAppend function appends a vertex to the end of an ST_LineString If the linestring has Z values or measures the vertex to be appended must also have Z values or measures Syntax SE_VertexAppend ST_LineString ST Point Return type ST_LineString The SE_VertexDelete function The SE_VertexDelete function deletes a vertex from a geometry You must supply the exact vertex to be deleted including Z value and measure if applicable All vertices in the geometry which match this value will be deleted Syntax SE_VertexDelete ST_Geometry ST Point Return type ST_Geometry The SE_VertexUpdate function The SE
211. his model expresses spatial relationships among all types of geometry as pair wise intersections of their interior boundary and exterior with consideration for the dimension of the resulting intersections Given geometries a and b I a B a and E a represent the interior boundary and exterior of a and I b B b and E b represent the interior boundary and exterior of b The intersections of I a B a and E a with I b B b and E b produce a 3 by 3 matrix Each intersection can result in geometries of different dimensions For example the intersection of the boundaries of two polygons could consist of a point and a linestring in which case the dim function would return the maximum dimension of 1 The dim function returns a value of 1 0 1 or 2 The 1 corresponds to the null set that is returned when no intersection was found or dim Table 7 1 Results of intersections Interior Boundary Exterior Interior dim I a I b dim I a B b dim I a E b Boundary dim B a I b dim B a B b dim B a E b Exterior dim E a I b dim E a B b dim E a E b The results of the spatial relationship for the functions described in Functions that determine spatial relationships on page 7 1 can be understood or verified by comparing the results with a pattern matrix that represents the acceptable values for the DE 9IM The pattern matrix contains the acceptable values for each of the intersection matrix cell
212. honeycomb VALUES 3 O polygon 17 7 20 7 22 10 20 13 17 13 15 10 17 7 INSERT INTO honeycomb VALUES 4 O polygon 15 10 17 13 15 16 12 16 10 13 12 10 15 10 SELECT SE_Dissolve hex_cell FROM honeycomb se_dissolve MULTIPOLYGON 5 10 7 7 107 12 4 15 4 17 7 20 7 22 10 20 13 17 13 15 16 12 16 10 13 7 13 5 10 Related reference The SE_Dissolve function on page 7 11 The ST_Distance function 8 32 The ST_Distance function returns the shortest distance separating two geometries Syntax ST_Distance gl ST Geometry g2 ST_Geometry Return type DOUBLE PRECISION Example The city engineer needs a list of all buildings within one foot of any lot line The building id column of the buildingfootprints table uniquely identifies each building The lot_id column identifies the lot each building belongs to The footprints multipolygon stores the geometry of each building s footprint CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon The lots table stores the lot_id that uniquely identifies each lot and the lot ST_MultiPolygon that contains the lot geometry CREATE TABLE lots lot_id integer lot ST_MultiPolygon The following query returns a list of building IDs that are within one foot of their lot lines The ST_Distance function performs a spatial join on the footprints and lot ST_MultiPolygon columns However the equijoin between bf
213. ilinestring 10 01 20 01 20 01 20 01 30 01 20 01 30 01 20 01 40 01 20 01 50 01 20 01 1000 E INSERT INTO envelope_test VALUES Multilinestring ST_MLineFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 INSERT INTO envelope_test VALUES Multipolygon IBM Informix Spatial Data User s Guide ST_MPolyFromText multipolygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 s The following query lists the subclass name and its envelope The ST_Envelope function returns a point a linestring or a polygon SELECT geotype ST_Envelope gl Envelope FROM envelope_test geotype envelope geotype envelope geotype envelope geotype envelope geotype envelope geotype envelope geotype envelope geotype envelope Point 1000 POINT 10 02 20 01 Linestring 1000 LINESTRING 10 01 20 01 10 01 40 01 Linestring 1000 POLYGON 10 02 20 01 11 92 20 01 11 92 25 64 10 02 25 64 10 02 20 01 Polygon 1000 1000 1000 1000 1000 Mul ti Mul ti Mul ti Mul ti POLYGON point POLYGON 10 02 20 01 25 02 20 01 25 02 35 64 10 02 35 64 10 02 20 01 10 02 20 01 11 92 20 01 11 92 25 64 10 02 25 64 10 02 20 01 linestring LINESTRING 10 01 20 01 50 01 20 01 linestring POLYGON polygon POLYGON 9 55 20 01 15 36
214. indParameter hstmt 1 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR species_len 0 species species _len amp pcbvaluel Bind the genus to the second parameter pcbvalue2 genus_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHAR genus_len 0 genus genus_len amp pcbvalue2 Bind the sitings geometry to the third parameter pcbvalue3 sitings_wkb_len rc SQLBindParameter hstmt 3 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR sitings_wkb_len 0 sitings_wkb_ buf sitings_wkb_ len amp pcbvalue3 Execute the insert statement rc SQLExecute hstmt The ST_MPolyFromGML function 8 76 The ST_MPolyFromGMLJ function takes a GML2 or GML3 string representation of an ST_MultiPoly and an optional spatial reference ID and returns a multipart polygon object Syntax ST_MPolyFromGML gmlstring lvarchar ST_MPolyFromGML gmlstring lvarchar SRID integer Return type ST_MultiPolygon Example The test_multipoly table is created with the INTEGER column id and the ST_MultiPolygon column geom CREATE TABLE test_multipoly id INTEGER geom ST _MultiPolygon INSERT INTO test_multipoly VALUES 1 ST_MPolyFromGML lt gm1 MultiPolygon srsName EPSG 4326 srsDimension 2 gt lt gm1 PolygonMember gt lt gm1 Polygon srsName EPSG 4326 srsDimension 2 gt lt gml exterior gt lt gml LinearRing gt lt gml posList dimension 2 gt 94 36 32 49 92 66 32 69 92 15 32 46 93 09
215. ineFromText function 3 1 8 71 ST_MLineFromWKB function 3 2 8 71 ST_MPointFromGML function 3 3 8 72 ST_MPointFromKML function 3 4 ST_MPointFromText 8 75 ST_MPointFromText function 3 1 ST_MPointFromWKB function 3 2 8 75 ST_MPolyFromGML function 3 3 8 76 ST_MPolyFromKML function 3 4 8 77 ST_MpolyFromText function 8 78 ST_MPolyFromText function 3 1 ST_MpolyFromWKB function 8 79 ST_MPolyFromWKB function 3 2 ST_MultiLineString type 2 7 ST_MultiPoint type 2 7 7 13 ST_MultiPolygon type 2 8 7 12 ST_NumGeometries function 2 1 8 81 ST_NumInteriorRing function 2 6 8 82 ST_NumPoints function 2 5 8 82 ST_Overlaps function 1 1 7 4 8 83 ST_Perimeter function 8 86 ST_Point type 2 4 ST_Point function 8 87 ST_PointFromGML function 3 3 8 88 ST_PointFromKML function 3 4 8 89 ST_PointFromText function 3 1 8 90 C 4 ST_PointFromWKB function 3 2 8 90 ST_PointN function 2 5 8 91 ST_PointOnSurface function 2 6 2 8 8 92 ST_PolyFromGML function 8 93 ST_PolyFromKML function 3 4 8 94 ST_PolyFromShape function 3 3 ST_PolyFromText function 3 1 8 95 ST_PolyFromWKB function 3 2 8 96 ST_Polygon type 2 6 7 12 ST_Polygon function 8 97 ST_Relate function 8 97 ST_SRID function 8 100 ST_Startpoint function 2 5 ST_StartPoint function 8 102 ST_Symdifference function 7 10 8 103 ST_Touches function 7 3 8 104 ST_Transform function 8 106 ST_Union function 7 9 8 108 ST
216. ineFromText WKT lvarchar SRID integer Return type ST_LineString Example The linestring_test table is created with a single In1 ST_LineString column CREATE TABLE linestring_ test In1 ST _LineString The following INSERT statement inserts an ST_LineString into the In1 column using the ST_LineFromText function INSERT INTO linestring_test VALUES ST_LineFromText linestring 10 01 20 03 20 94 21 34 35 93 19 04 1000 s The ST_LineFromWKB function The ST_LineFromWKB function takes a well known binary representation of type ST_LineString and a spatial reference ID returning an ST_LineString Syntax ST_LineFromWKB wkb lvarchar SRID integer Return type ST_LineString Chapter 8 Spatial functions 8 63 Example The sewerlines table is created with three columns The first column sewer_id uniquely identifies each sewer line The INTEGER class column identifies the type of sewer line generally associated with the line capacity The sewer ST_LineString column stores the sewer line geometries CREATE TABLE sewerlines sewer_id integer class integer sewer ST_LineString This code fragment populates the sewerlines table with the unique ID class and geometry of each sewer line Create the SQL insert statement to populate the sewerlines table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sq l_stmt INSERT INTO sewerlines s
217. ing ST_Point NS lt 7 CF ST_LineString ST_MultiPoint ST_Polygon ST_Point ST_Polygon ST_MultiPoint ST_LineString ST_LineString ST_Polygon ST_LineString ST_Polygon ST_Polygon Figure 7 8 Contained geometries Related reference The ST_Contains function on page 8 21 Functions that produce a new geometry Some functions compare two existing geometries and return a new geometry based on how the two geometries are related For example the ST_Difference function returns that portion of the first geometry that is not intersected or overlapped by the second The ST_Intersection function The ST_Intersection function returns the intersection set of two geometries The intersection set is returned as a collection that is the minimum dimension of the source geometries For example for an ST_LineString that intersects an ST_Polygon the ST_Intersection function returns that portion of the ST_LineString common to the interior and boundary of the ST_Polygon as an ST_MultiLineString The ST_MultiLineString contains more than one ST_LineString if the source ST_LineString intersects the ST_Polygon with two or more discontinuous segments If the geometries do not intersect or if the intersection results in a dimension less than both source geometries an empty geometry is returned The following figure illustrates some examples of the ST_Intersection function Chapter 7 Determine spatial relationships and transform geometrie
218. int Tagged Text gt POINT lt Point Text gt lt LineString Tagged Text gt LINESTRING lt LineString Text gt lt Polygon Tagged Text gt POLYGON lt Polygon Text gt lt MultiPoint Tagged Text gt MULTIPOINT lt Multipoint Text gt lt MultiLineString Tagged Text gt MULTILINESTRING lt MultiLineString Text gt lt MultiPolygon Tagged Text gt MULTIPOLYGON lt MultiPolygon Text gt lt Point Text gt EMPTY lt Point gt Z lt PointZ gt M lt PointM gt ZM lt PointZM gt lt Point gt lt x gt lt y gt lt x gt double precision literal lt y gt double precision literal lt PointZ gt lt x gt lt y gt lt z gt lt x gt double precision literal lt y gt double precision literal lt z gt double precision literal lt PointM gt lt x gt lt y gt lt m gt lt x gt double precision literal lt y gt double precision literal lt m gt double precision literal lt PointZM gt lt x gt lt y gt lt z gt lt m gt Copyright IBM Corp 2001 2010 C 1 lt x gt double precision literal lt y gt double precision literal lt z gt double precision literal lt m gt double precision literal lt LineString Text gt EMPTY lt Point Text gt lt Point Text gt Z lt PointZ Text gt lt PointZ Text gt M lt PointM Text gt lt PointM Text gt ZM lt PointZM Text gt lt PointZM Text gt
219. intN function on page 8 9 Returns the length The ST_Length function on page 8 5 Creates an ST_Polygon from a ring closed linestring The ST_Polygon function on page 8 9 8 4 IBM Informix Spatial Data User s Guide Table 8 1 Spatial functions by task type continued Function task type Description Function name Manipulate the ST_Polygon and Calculates the area ST_MultiPolygon data types Obtain parameters of a geometry o Q oO The ST_Area function on L Calculates the geometric center The ST_Centroid function on page 8 2 Returns the exterior ring Counts the number of interior rings The ST_ExteriorRing function on page 8 39 The ST_NumInteriorRing unction on page 8 82 ER Returns the nth interior ring E J oO WN 4 hes oO 2 e 5 g 5 Fa 2 za No unction on page 8 4 Returns a point on the surface E a oO ioe fe i O 5 3 Q 5 ice Cc F o O o 0 p unction on page 8 92 Returns the perimeter n E a oO ioe ae io a zi a oO 5 fa Q ch 5 page 8 8 Returns the dimensions of the coordinates The ST_CoordDim function on page 8 2 Returns the dimension of the geometry The ST_Dimension function Ko on page 8 2 Returns the shortest distance to another geometry The
220. ion on page 8 102 The ST_Envelope function The ST_Envelope function returns the bounding box of a geometry object Chapter 8 Spatial functions 8 33 8 34 This is usually a rectangle but the envelope of a point is the point itself and the envelope of a horizontal or vertical linestring is a linestring represented by the endpoints of the source geometry Syntax ST_Envelope gl ST_Geometry Return type ST_Geometry Example The geotype column of the envelope_test table stores the name of the geometry subclass stored in the g1 ST_Geometry column CREATE TABLE envelope test geotype varchar 20 gl ST_Geometry The following INSERT statements insert each geometry subclass into the envelope_test table INSERT INTO envelope_test VALUES Point ST_PointFromText point 10 02 20 01 1000 INSERT INTO envelope_test VALUES Linestring ST_LineFromText linestring 10 01 20 01 10 01 30 01 10 01 40 01 1000 INSERT INTO envelope_test VALUES Linestring ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO envelope_test VALUES Polygon ST_PolyFromText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 INSERT INTO envelope _test VALUES Multipoint ST_MPointFromText multipoint 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO envelope_test VALUES Multilinestring ST_MLineFromText mult
221. ion The ST_Crosses function The ST_Within function The ST_Contains function Chapter 8 Spatial functions Summary of spatial functions by task a The ST_Area function var iv IBM Informix Spatial Data User s Guide z372 3 3 3 4 4 1 4 1 4 3 4 4 4 4 4 5 5 1 5 1 sl 6 1 6 1 6 1 7 3 7 6 n 7 9 7 10 7 11 7 12 7 12 lt 7 18 7 14 7 14 715 7 16 7 17 7 17 7 17 7 18 7 19 7 20 7 20 7 21 8 1 8 1 8 8 The ST_AsBinary function The SE_AsGML function The ST_AsGML function The SE_AsKML function The ST_AsKML function The SE_AsShape function The ST_AsText function The ST_Boundary function The SE_BoundingBox function The ST_Buffer function The ST_Centroid function The ST_Contains function The ST_ConvexHull function The ST_CoordDim function The SE_CreateSRID function The SE_CreateSrtext function The ST_Crosses function The ST_Difference function The ST_Dimension function The ST_Disjoint function The SE_Dissolve function The ST_Distance function The ST_EndPoint function The ST_Envelope function The ST_EnvelopeAsGML function The SE_EnvelopeAsKML function The ST_EnvelopeFromGML function The SE_EnvelopeFromKML function The SE_EnvelopesIntersect function The ST_Equals function F The ST_ExteriorRing function
222. ion failed to release this lock another session may not be able to obtain access User response To forcibly reset the lock run the following SQL statement EXECUTE FUNCTION SE MetadatalInit USE53 Spatial datablade assert failure File FILE line LINE Explanation A programmatic error has occurred in the Spatial DataBlade module Contact IBM Informix Technical Support USE54 You must create a default sbspace before you can register the Spatial DataBlade Explanation When the Spatial DataBlade is registered a small 8 KB smart large object is created and stored in the default sbspace Registration fails if there is no default sbspace This smart large object can be moved to a non default sbspace after registration is complete instructions for moving it are provided in the release notes 674 Routine YFUNCTION cannot be resolved Explanation This error message is generally returned by the IBM Informix server whenever you try to apply the function to a non supported type User response Check the geometry type entered and resubmit the function Appendix G Error messages G 5 G 6 IBM Informix Spatial Data User s Guide Appendix H Accessibility IBM strives to provide products with usable access for everyone regardless of age or ability Accessibility features for IBM Informix products Accessibility features help a user who has a physical disability such as restricted mobility or
223. ional Index You cannot use the SE_BoundingBox function on a functional R tree index Instead you must use the rtreeRootBB function The rtreeRootBB function takes the index name and type name as arguments and returns the well known text representation of an ST_Polygon as shown in the following example CREATE TABLE xytab x float y float srid int INSERT INTO xytab VALUES 1 2 0 INSERT INTO xytab VALUES 3 4 0 CREATE INDEX point_idx ON xytab ST_Point x y srid ST Geometry_ops USING RTREE IBM Informix Spatial Data User s Guide EXECUTE FUNCTION rtreeRootBB point_idx st_point expression POLYGON 1 2 3 2 3 4 1 4 1 2 See also The ST_Envelope function on page 8 33 The ST_Buffer function The ST_Buffer function takes a geometry object and distance and returns a geometry object that is the buffer surrounding the source object Syntax ST_Buffer gl1 ST_Geometry distance double_precision Return type ST_Geometry Example The county supervisor needs a list of hazardous sites whose five mile radius overlaps sensitive areas such as schools hospitals and nursing homes The sensitive areas are stored in the table sensitive_areas that is created with the CREATE TABLE statement shown below The zone column defined as a ST_Polygon stores the outline of each of the sensitive areas CREATE TABLE sensitive areas id integer name varchar 128 size float type varchar 10 zone
224. ipolygon always returns a multilinestring boundary dimension 1 CREATE TABLE boundary_test geotype varchar 20 gl ST_Geometry INSERT INTO boundary_test VALUES Point ST _PointFromText point 10 02 20 01 1000 s INSERT INTO boundary_test VALUES Linestring ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO boundary_test VALUES Polygon ST_PolyFromText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 s INSERT INTO boundary_test VALUES Multipoint ST_MPointFromText multipoint 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO boundary_test VALUES Multilinestring ST_MLineFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 s INSERT INTO boundary_test VALUES Multipolygon ST_MPolyFromText multipolygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 ys SELECT geotype ST Boundary g1 FROM boundary_test geotype Point expression 1000 POINT EMPTY geotype Linestring expression 1000 MULTIPOINT 10 02 20 01 11 92 25 64 geotype Polygon expression 1000 MULTILINESTRING 10 02 20 01 19 15 33 94 25 02 34 15 11 92 35 64 10 02 20 01 geotype Multipoint expression 1000 POINT EMPTY geotype Multilinestring Chapter 8 Spatial functions 8 17 expressi
225. is a XYZM point ST_PointFromGML lt gm Point srsName DEFAULT srsDimension 4 gt lt gm l pos gt 10 02 20 01 5 7 lt gml pos gt lt gm1 Point gt 1000 INSERT INTO point_t VALUES IBM Informix Spatial Data User s Guide 5 This point is an empty point ST_PointFromGML lt gm l Point xsi nil true srsName UNKNOWN 0 srsDimension 2 gt 1000 The ST_PointFromKML function The ST_PointFromKML function takes a KML Point string and an optional spatial reference ID and returns a point object A Point string can contain the elements of lt coordinates gt lt extrude gt lt tessellate gt and lt altitudeMode gt Syntax ST_PointFromKML kmlstring lvarchar ST_PointFromKML kmlstring lvarchar SRID integer Return type ST_Point Example EXECUTE FUNCTION ST_PointFromKML lt Point gt lt coordinates gt 122 44255879 37 80666418 lt coordinates gt lt Point gt 3 3 Output 3 POINT 122 44255879 37 80666418 The SE_PointFromShape function The SE_PointFromShape function creates an ST_Point from a shape of type point and a spatial reference ID Syntax SE_PointFromShape s1 lvarchar SRID integer Return type ST_Point Example The hazardous sites are stored in the hazardous_sites table created with the CREATE TABLE statement that follows The location column defined as a point stores a location that is the geographic center of each hazardous site CREATE TABLE hazardous sites
226. is the only item with that dotted decimal number The symbol like the symbol is equivalent to a loop back line in a railroad syntax diagram Appendix H Accessibility H 3 H 4 IBM Informix Spatial Data User s Guide Notices This information was developed for products and services offered in the U S A IBM may not offer the products services or features discussed in this document in other countries Consult your local IBM representative for information on the products and services currently available in your area Any reference to an IBM product program or service is not intended to state or imply that only that IBM product program or service may be used Any functionally equivalent product program or service that does not infringe any IBM intellectual property right may be used instead However it is the user s responsibility to evaluate and verify the operation of any non IBM product program or service IBM may have patents or pending patent applications covering subject matter described in this document The furnishing of this document does not grant you any license to these patents You can send license inquiries in writing to IBM Director of Licensing IBM Corporation North Castle Drive Armonk NY 10504 1785 U S A For license inquiries regarding double byte DBCS information contact the IBM Intellectual Property Department in your country or send inquiries in writing to Intellectual Property Licensing L
227. isplayed on the console D The database name e optional The last row in the shapefile to load ext optional Specifies the initial extent size for the table to be loaded This option is not valid in the append option of the o flag f The path and name of the ESRI shapefile to be loaded ic optional Specifies use of an INSERT CURSOR Using an INSERT CURSOR to load data significantly reduces load time but limits the client program s ability to handle errors INSERT CURSORs IBM Informix Spatial Data User s Guide buffer rows before writing them to the database to improve performance If an error is encountered during the load all buffered rows following the last successfully inserted row are discarded in optional Specifies the dbspace in which to create the table to be loaded This option is not valid in the append option of the o flag l The table and geometry column to load data into log optional Specifies whether to write information about the status of data loading to a log file The log file has the same name as the shapefile you are loading from with the extension 1og If you do not specify a directory the log file is created in the same directory as the shapefile you are loading from next Specifies the next extent size for the table to be loaded This option is not valid in the append option of the o flag noidx optional Specifies that indexes should not be built and statistics should not be
228. isting facilities that would violate the proposed regulation the GIS manager has to buffer the hazardous_sites locations to see if any rivers or streams cross the buffer polygons The ST_Crosses function compares the buffered hazardous_sites with waterways returning only those records where the waterway crosses over the county s proposed regulated radius SELECT ww name waterway hs name hazardous_site FROM waterways ww hazardous_sites hs WHERE ST _Crosses ST_ Buffer hs location 5 5280 ww water waterway Fedders creek hazardous_site Landmark Industrial The following figure shows that the five mile buffered radius of the hazardous waste sites crosses the stream network that runs through the county s administrative district Because the stream network is defined as an ST_MultiLineString all linestring segments that are part of those segments that cross the radius are included in the result set Chapter 8 Spatial functions 8 27 Waterways Figure 8 4 Hazardous waste sites and the stream network Related reference The ST_Crosses function on page 7 4 The ST_Crosses function on page 7 20 The ST_Difference function 8 28 The ST_Difference function takes two geometry objects and returns a geometry object that is the difference of the source objects Syntax ST_Difference g1 ST Geometry g2 ST Geometry Return type ST_Geometry Example The city engineer needs to know the
229. iver system stored in the table The water column is a multilinestring because the river and stream systems are often an aggregate of several linestrings CREATE TABLE waterways id integer name varchar 128 water ST_MultiLineString The query returns the name of each system along with the length of the system generated by the length function SELECT name ST _Length water Length FROM waterways name Fedders creek length 175853 9869703 The following figure displays the river and stream systems that lie within the county boundary County Boundary Figure 8 9 Stream and river systems The ST_LineFromGML function The ST_LineFromGML function takes a GML2 or GML3 string representation of an ST_LineString and an optional spatial reference ID and returns a polyline object 8 60 IBM Informix Spatial Data User s Guide Syntax ST_LineFromGML gmlstring lvarchar ST_LineFromGML gmlstring lvarchar SRID integer Return type ST_LineString Example The gml_linetest table is created with the SMALLINT column gid and the ST_LineString column In1 CREATE TABLE gml_linetest gid smallint In1 ST_LineString INSERT INTO gml_linetest VALUES 1 ST_LineFromGML lt gml LineString gt lt gml posList gt 110 45 45 256 109 48 46 46 109 86 43 84 lt gm1 posList gt lt gml LineString gt 4 INSERT INTO gml_linetest VALUES 2 ST_LineFromGML lt gml LineString srsName EPSG 4326 srsDimension 3 gt
230. kes a homogeneous collection and returns the number of base geometry elements it contains The ST_GeometryN function takes a homogeneous collection and an index and returns the nth base geometry Properties of spatial data types The OGC in its publication of OpenGIS Features for ODBC SQL Implementation Specification selected the term geometry to represent spatial features such as point locations and polygons Typically points represent an object at a single location linestrings represent a linear characteristic and polygons represent a spatial extent An abstract definition of the OpenGIS noun geometry might be a point or aggregate of points symbolizing a feature on the ground The ST_Geometry data type is an abstract noninstantiable superclass Its subclasses provide instantiable data types This means you can define table columns to be of such types The following figure shows the class hierarchy for the IBM Informix spatial data types Copyright IBM Corp 2001 2010 2 1 ST_Geometry ST_Curve ST_Surface ST_Point ST_GeomCollection ST_LineString ST_Polygon ST_MultiSurface ST_MultiCurve ST_MultiPoint ST_MultiPolygon ST_MultiLineString italics represent a noninstantiable class Figure 2 1 Data types class diagram Throughout the remainder of this publication the terms geometry or geometries collectively refer to the superclass ST_Geometry data type and all of its subclass data types Whenever it is necessary to
231. l data for display in a window The easiest way to do this is to define a polygon representing the boundary of the window and then use the SE_EnvelopesIntersect function to find all spatial objects that overlap this window For example SELECT name type zone FROM sensitive_areas WHERE SE_EnvelopesIntersect zone ST_PolyFromText polygon 20000 20000 60000 20000 60000 60000 20000 60000 20000 20000 5 Queries can also use spatial columns in the SQL WHERE clause to qualify the result set the spatial column does not need to be in the result set at all For example the following SQL statement retrieves each sensitive area with its nearby hazardous waste site if the sensitive area is within five miles of a hazardous site The ST_Buffer function generates a circular polygon representing the five mile radius around each hazardous location The ST_Polygon geometry returned by the ST_Buffer function becomes the argument of the ST_Overlaps function which returns t TRUE if the zone ST_Polygon of the sensitive_areas table overlaps the ST_Polygon generated by the ST_Buffer function SELECT sa name sensitive_area hs name hazardous site FROM sensitive_areas sa hazardous sites hs WHERE ST Overlaps sa zone ST Buffer hs location 26400 sensitive_area Summerhill Elementary School hazardous_site Landmark Industrial sensitive_area Johnson County Hospital hazardous_site Landmark Industrial Related reference Chapter 5 Run p
232. l extension and the IBM Informix Geodetic DataBlade Module both manage GIS data in an IBM Informix database These products use different core technologies that solve different problems and complement each other e The IBM Informix Geodetic DataBlade Module treats the Earth as a globe It uses a latitude and longitude coordinate system on an ellipsoidal Earth model Geometric operations are precise regardless of location The Geodetic DataBlade module is best used for global data sets and applications such as satellite imagery repositories e The IBM Informix spatial extension treats the Earth as a flat map It uses planimetric flat plane geometry which means that it approximates the round surface of the Earth by projecting it onto flat planes using various transformations This leads to some distortion around the edges of the map The IBM Informix spatial extension is best used for regional data sets and applications such as those shown in the examples in this publication Overview of using spatial data 1 2 You can create tables that contain Informix spatial data type columns You can insert and store geographic features in the spatial columns The following figure shows the architecture for IBM Informix and spatial applications The IBM Informix server can communicate to Java applications through the Informix JDBC Driver C applications through the IBM Informix ODBC Driver directly with ESQL C applications and DB Access
233. le format using the SE_PolyFromShape and ST_PointFromShape functions or in well known binary format using the ST_PolyFromWKB and ST_PointFromWKB functions Chapter 1 Getting started with spatial data 1 9 1 10 INSERT INTO sensitive_areas VALUES 1 408 Summerhill Elementary School 67920 64 school ST_PolyFromText polygon 52000 28000 58000 28000 58000 23000 52000 23000 52000 28000 5 s INSERT INTO hazardous_sites VALUES 1 102 W H Kleenare Chemical Repository ST_PointFromText point 17000 57000 5 s Alternatively you can use the IBM Informix load format in which case a conversion function is not required INSERT INTO sensitive_areas VALUES 2 129 Johnson County Hospital 102281 91 hospital 5 polygon 32000 55000 32000 68000 38000 68000 38000 52000 35000 52000 35000 55000 32000 55000 s INSERT INTO hazardous _sites VALUES 2 59 Landmark Industrial 5 point 58000 49000 In the simple example above a few records are inserted into database tables However the actual amount of data loaded into a GIS system usually ranges between ten thousand records for smaller systems and one hundred million records for larger systems The IBM Informix database server can handle the entire range Loading methods You have several options for loading data If you are performing a bulk load of data you can avoid large numbers of log records by temporarily turning off logging for
234. letely within a lot SELECT building_id FROM buildingfootprints lots WHERE ST _Within footprint lot building_id 506 543 178 The city engineer realizes that although the first query produces a list of all building IDs that have footprints outside a lot polygon it does not ascertain whether the rest have the correct lot_id assigned to them This second query performs a data integrity check on the lot_id column of the buildingfootprints table SELECT bf building_id bf lot_id bldg_lot_id lots lot_id lots_lot_id FROM buildingfootprints bf lots WHERE ST _Within footprint lot AND lots lot_id lt gt bf lot_id IBM Informix Spatial Data User s Guide building_id bldg_lot_id lots_lot_id 178 5192 203 Related reference The ST_Within function on page 7 5 The ST_Within function on page 7 20 The ST_WKBToSQL function The ST_WKBToSQL function constructs an ST_Geometry given its well known binary representation The SRID of the ST_Geometry is 0 Syntax ST_WKBToSQL WKBGeometry lvarchar Return type ST_Geometry Example The following CREATE TABLE statement creates the lots table which has two columns lot_id which uniquely identifies each lot and the lot polygon column which contains the geometry of each lot CREATE TABLE lots lot_id integer lot ST_MultiPolygon The following C code fragment contains ODBC functions included with the spatial data type functions that insert data into the l
235. limited vision to use information technology products successfully Accessibility features The following list includes the major accessibility features in IBM Informix products These features support e Keyboard only operation e Interfaces that are commonly used by screen readers e The attachment of alternative input and output devices Tip The information center and its related publications are accessibility enabled for the IBM Home Page Reader You can operate all features by using the keyboard instead of the mouse Keyboard navigation This product uses standard Microsoft Windows navigation keys Related accessibility information IBM is committed to making our documentation accessible to persons with disabilities Our publications are available in HTML format so that they can be accessed with assistive technology such as screen reader software You can view the publications in Adobe Portable Document Format PDF by using the Adobe Acrobat Reader IBM and accessibility See the IBM Accessibility Center at http www ibm com able for more information about the IBM commitment to accessibility Dotted decimal syntax diagrams The syntax diagrams in our publications are available in dotted decimal format which is an accessible format that is available only if you are using a screen reader In dotted decimal format each syntax element is written on a separate line If two or more syntax elements are always present tog
236. lot_id and lots lot_id ensures that only the ST_MultiPolygons belonging to the same lot are compared by the ST_Distance function IBM Informix Spatial Data User s Guide SELECT bf building_id FROM buildingfootprints bf lots WHERE bf lot_id lots lot_id AND ST_Distance footprint lot lt 1 0 The ST_EndPoint function The ST_EndPoint function returns the last point of a linestring Syntax ST_EndPoint 1n1 ST_LineString Return type ST_Point Example The endpoint_test table stores the gid INTEGER column which uniquely identifies each row and the In1 ST_LineString column that stores linestrings CREATE TABLE endpoint_test gid integer Jnl ST_LineString The following INSERT statements insert linestrings into the endpoint_test table The first linestring does not have Z coordinates or measures while the second one does INSERT INTO endpoint_test VALUES l ST_LineFromText linestring 10 02 20 01 23 73 21 92 30 10 40 23 1000 INSERT INTO endpoint_test VALUES 2 ST_LineFromText linestring zm 10 02 20 01 5 0 7 0 23 73 21 92 6 5 7 1 30 10 40 23 6 9 7 2 1000 The following query lists the gid column with the output of the ST_EndPoint function The ST_EndPoint function generates an ST_Point geometry SELECT gid ST_EndPoint 1n1 Endpoint FROM endpoint_test gid 1 endpoint 1000 POINT 30 1 40 23 gid 2 endpoint 1000 POINT ZM 30 1 40 23 6 9 7 2 See also The ST_StartPoint funct
237. mText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 s INSERT INTO geometry_test VALUES 4 ST_GeomFromText multipoint 10 02 20 01 10 32 23 98 11 92 25 64 1000 s INSERT INTO geometry_test VALUES 5 ST_GeomFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 s INSERT INTO geometry_test VALUES 6 ST_GeomFromText multipolygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 s The ST_GeomFromWKB function The ST_GeomFromWKB function takes a well known binary representation and a spatial reference ID to return a geometry object Chapter 8 Spatial functions 8 47 Syntax ST_GeomFromWKB WKB lvarchar SRID integer Return type ST_Geometry Example The following C code fragment contains ODBC functions included with the IBM Informix spatial data type functions that insert data into the lots table The lots table was created with two columns the lot_id which uniquely identifies each lot and the lot polygon column which contains the geometry of each lot CREATE TABLE lots lot_id integer lot ST_MultiPolygon The ST_GeomFromWKB function converts WKB representations into Informix spatial geometry The entire INSERT statement is copied into a wkb_sql CHAR string The INSERT statement contains parameter markers to accep
238. mber_of_points FROM numpoints_test geotype number_of_points point 1 linestring 2 polygon 5 The SE_OutOfRowSize function The SE_OutOfRowSize function returns the size of the out of row portion of a geometry Geometries which are larger than 930 bytes for example polygons with many vertices have an in row component and an out of row component the out of row component is stored in an sbspace If a geometry has no out of row component SE_OutOfRowSize returns 0 You can use this function to obtain an estimate of the amount of diskspace consumed by one or more geometries However this function does not account for dbspace and sbspace overhead so cannot be used to obtain an exact total Syntax SE_OutOfRowSize ST_Geometry Return type INTEGER See also The SE_InRowSize function on page 8 48 The SE_TotalSize function on page 8 104 The ST_Overlaps function The ST_Overlaps function takes two ST_Geometry objects and returns t TRUE if the intersection of the objects results in an ST_Geometry object of the same dimension but not equal to either source object otherwise it returns f FALSE Syntax ST_Overlaps gl ST Geometry g2 ST Geometry Chapter 8 Spatial functions 8 83 8 84 Return type BOOLEAN Example The county supervisor needs a list of hazardous waste sites whose five mile radius overlaps sensitive areas The sensitive_areas table contains several columns that describe the thr
239. measures while the second linestring has both INSERT INTO pointn_test VALUES 1 ST_LineFromText linestring 10 02 20 01 23 73 21 92 30 10 40 23 1000 s INSERT INTO pointn_test VALUES 2 ST_LineFromfext linestring zm 10 02 20 01 5 0 7 0 23 73 21 92 5 7 1 30 10 40 23 6 9 7 2 1000 6 The query lists the gid column and the second vertex of each linestring The first row results in an ST_Point without a Z coordinate or measure while the second row results in an ST_Point with a Z coordinate and a measure The ST_PointN function will also include a Z coordinate or measure value if they exist in the source linestring SELECT gid ST_PointN 1n1 2 the_2nd_vertex FROM pointn_test gid 1 the_2nd_vertex 1000 POINT 23 73 21 92 gid 2 the_2nd_vertex 1000 POINT ZM 23 73 21 92 6 5 7 1 The ST_PointOnSurface function 8 92 The ST_PointOnSurface function takes an ST_Polygon or ST_MultiPolygon and returns an ST_Point guaranteed to lie on its surface Syntax ST_PointOnSurface p11 ST_Polygon ST_PointOnSurface mpl1 ST_MultiPolygon Return type ST_Point Example The city engineer wants to create a label point for each building footprint The buildingfootprints table that was created with the following CREATE TABLE statement stores the building footprints CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon IBM Informix Spatial Data User s Guide The ST
240. metry USE04 Function FUNCTION not applicable to type TYPE Explanation An invalid geometry type was passed to the function Valid geometry types are geometry point linestring polygon multipoint multilinestring and multipolygon User response Resubmit the function with one of the valid geometry types USE05 This function is not yet implemented Explanation The function has not been implemented Copyright IBM Corp 2001 2010 for the current release However it may be available in a future release USE06 Unknown ESRI shape library error ERRCODE in FUNCTION Explanation Contact IBM Informix Technical Support for assistance Please include this error number and any other related error messages and information from the INFORMIXDIR on1 ine log file If you are using the Spatial DataBlade module in conjunction with ArcSDE from ESRI please also include any related information from the SDEHOME etc sde errlog file USE07 Internal SAPI error SAPIFUNC returned RETVAL Failure in FUNCNAME Explanation An error has occurred in the SAPI subsystem of the IBM Informix server User response Contact IBM Informix Technical Support USE08 Nearest neighbor queries require an index scan Explanation An attempt was made to use a nearest neighbor function as a filter during a sequential scan of a table This is not supported USE09 Unknown or unsupported shape file typ
241. mine spatial relationships and transform geometries 7 13 J ane J oe 6 3 45 55 7 Figure 7 15 The SE_LocateAlong function Related reference The SE_LocateAlong function on page 8 64 The SE_LocateBetween function The SE_LocateBetween function returns the set of paths or locations that lie between two measure values from a source geometry If the source geometry dimension is 0 SE_LocateBetween returns an ST_MultiPoint consisting of all points whose measures lie between the two source measures For source geometries whose dimension is greater than 0 SE_LocateBetween returns an ST_MultiLineString if a path can be interpolated otherwise SE_LocateBetween returns an ST_MultiPoint containing the point locations An empty point is returned whenever SE_LocateBetween cannot interpolate a path or find a location between the measures SE_LocateBetween performs an inclusive search of the geometries therefore the geometry measures must be greater than or equal to the from measure and less than or equal to the to measure In the following figure SE_LocateBetween returns an ST_MultiLineString that is between measures 4 3 and 6 9 Figure 7 16 The SE_LocateBetween function Related reference The SE_LocateBetween function on page 8 65 The ST_ConvexHull function The ST_ConvexHull function returns the convex hull polygon of any geometry that has at least three vertices forming a convex
242. mple the KML LatLonBox includes four coordinates EXECUTE FUNCTION SE_EnvelopeFromKML lt LatLonBox gt lt north gt 34 54356 lt north gt lt south gt 33 543634 lt south gt lt east gt 83 21454 lt east gt lt west gt 86 432536 lt west gt 4 Output 4 POLYGON 86 3253600195 33 5436340112 83 2145400212 33 543630112 83 2145400212 34 5435600828 86 3253600195 34 5435600828 86 3253600195 33 5436340112 In this example the KML LatLonAltBox includes the four coordinates as well as the minAltitude maxAltitude and altitudeMode attributes EXECUTE FUNCTION SE_EnvelopeFromKML lt LatLonAltBox gt lt north gt 45 0 lt north gt lt south gt 42 0 lt south gt lt east gt 80 0 lt east gt lt west gt 82 0 lt west gt lt minAltitude gt 0 lt minAltitude gt lt maxAl titude gt 0 lt maxAltitude gt lt altitudeMode gt clampToGround lt altitudeMode gt 4 However the output only includes the four coordinates 4 POLYGON 82 0 42 0 80 0 42 0 80 0 45 0 82 0 45 0 82 0 42 0 The SE_Envelopesintersect function The SE_EnvelopesIntersect function returns t TRUE if the envelopes of two geometries intersect otherwise it returns f FALSE Syntax SE_EnvelopesIntersect gl ST_Geometry g2 ST Geometry Return type BOOLEAN Example The get_window function retrieves the display window coordinates from the application The window parameter is actually a polygon shape structure containing a string of
243. n ST_Polygon The ST_PolyFromText function on page 8 9 Takes a well known text representation and returns an ST_MultiLine The ST_MLineFromText unction on page 8 71 p Takes a well known text representation and returns an ST_MultiPoint The ST_MPointFromText unction on page 8 75 p Takes a well known text representation and returns an ST_MultiPolygon The ST_MPolyFromText unction on page 8 78 p Copyright IBM Corp 2001 2010 8 1 Table 8 1 Spatial functions by task type continued Function task type Description Function name Generate a geometry from a Takes a well known binary representation and The ST_WKBToSQL function well known binary returns an ST_Geometry using SRID 0 on page 8 111 representation Takes a well known binary representation and The ST_GeomFromWKB returns an ST_Geometry unction on page 8 4 En I Takes a well known binary representation and The ST_PointFromWKB returns an ST_Point unction on page 8 9 nl oOo Takes a well known binary representation and The ST_LineFromWKB returns an ST_LineString unction on page 8 6 nl W Takes a well known binary representation and The ST_PolyFromWKB returns an ST_Polygon unction on page 8 9 En oN Qo Takes a well known binary representation and The ST_MLineFromWKB returns an ST_MultiLine unction on page 8 7 ay a
244. nces table entries that are qualified to load the specified shapefiles create Creates a new entry in the spatial_references table for loading the specified shapefiles info Reports information extracted from the headers of the shp shx dbf and optional prj files associated with the specified shapefiles Command line switches You can use the infoshp command flags to specify the following options D The database name f The path and name of one or more ESRI shapefiles to process p optional The IBM Informix password If you specify the p option you must also specify the u option s optional The IBM Informix server Defaults to the value of the INFORMIXSERVER environment variable u optional The IBM Informix user name If you specify the u option you must also specify the p option V Prints version information for this utility The loadshp utility The loadshp utility loads spatial features and associated attributes from an ESRI shapefile into a table in an IBM Informix database When loadshp creates a table it inserts a row into the geometry_columns system table When you want to drop a table created by loadshp you should also delete the corresponding row from the geometry_columns table Tip The loadshp utility creates a primary key constraint on the se_row_id column of the table that you are loading A 2 IBM Informix Spatial Data User s Guide Syntax
245. nctions that insert data into the lots table The lots table was created with two columns lot_id which uniquely identifies each lot and the lot polygon column which contains the geometry of each lot CREATE TABLE lots lot_id integer lot ST_MultiPolygon The SE_ShapeToSQL function converts shapes into ST_Geometry values The INSERT statement contains parameter markers to accept the lot_id and the lot data dynamically Create the SQL insert statement to populate the lots table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO lots lot_id lot VALUES SE_ShapeToSQL Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the lot_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_SLONG SQL_INTEGER 0 O amp lot_id 0 amp pcbvaluel Bind the lot geometry the second parameter pcbvalue2 lot_shape_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C BINARY SQL_INFX_UDT_LVARCHAR lot_shape_len 0 lot_shape_buf lot_shape_len amp pcbvalue2 Execute the insert statement rc SQLExecute hstmt The SE_SpatialKey function The SE_SpatialKey function generates a sort key for an ST_Geometry A sort key is a numeric value that can be used to sort spatial objects acco
246. nd the lot_id to the first parameter pcebvaluel 0 rc SQLBindParameter hstmt 1 SQL PARAM _INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp lot_id 0 amp pcbvaluel Bind the lot geometry to the second parameter pcbvalue2 lot_shape_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR lot_shape_len 0 lot_shape_buf lot_shape_len amp pcbvalue2 Execute the insert statement rc SQLExecute hstmt IBM Informix Spatial Data User s Guide The ST_GeomFromText function The ST_GeomFromText function takes a well known text representation and a spatial reference ID and returns a geometry object Syntax ST_GeomFromText wkt lvarchar SRID integer Return type ST_Geometry Example The geometry_test table contains the INTEGER gid column which uniquely identifies each row and the g1 column which stores the geometry CREATE TABLE geometry_test gid smallint gl ST Geometry The following INSERT statements insert the data into the gid and g1 columns of the geometry_test table The ST_GeomFromText function converts the text representation of each geometry into its corresponding instantiable subclass INSERT INTO geometry_test VALUES 1 ST_GeomFromText point 10 02 20 01 1000 INSERT INTO geometry_test VALUES 2 ST_GeomFromText linestring 10 01 20 01 10 01 30 01 10 01 40 01 1000 J INSERT INTO geometry_test VALUES 3 ST_GeomFro
247. nerate a new geometry from an existing geometry and a formula The ST_Buffer function The ST_Buffer function generates a geometry by encircling a geometry at a specified distance A single polygon results when a primary geometry is buffered or when the buffer polygons of a collection are close enough to overlap When enough separation exists between the elements of a buffered collection individual buffer ST_Polygons result in an ST_MultiPolygon The ST_Buffer function accepts both positive and negative distances but only geometries with a dimension of 2 ST_Polygon and ST_MultiPolygon can apply a negative buffer The absolute value of the buffer distance is used when the dimension of the source geometry is less than 2 all geometries that are neither ST_Polygon nor ST_MultiPolygon Generally speaking positive buffer distances generate polygon rings that are away from the center of the source geometry and for the exterior ring of a ST_Polygon or ST_MultiPolygon toward the center when the distance is negative For interior rings of an ST_Polygon or ST_MultiPolygon the buffer ring is toward the center when the buffer distance is positive and away from the center when it is negative The buffering process merges buffer polygons that overlap Negative distances greater than one half the maximum interior width of a polygon result in an empty geometry IBM Informix Spatial Data User s Guide As shown in the following figure ST_Buffer
248. niquely identifies the rows of the table and the In1 ST_LineString column CREATE TABLE startpoint_test gid integer Inl ST_LineString The following INSERT statements insert the ST_LineStrings into the In1 column The first ST_LineString does not have Z coordinates or measures while the second ST_LineString has both INSERT INTO startpoint_test VALUES 1 ST_LineFromText linestring 10 02 20 01 23 73 21 92 30 10 40 23 1000 INSERT INTO startpoint_test VALUES 2 ST_LineFromText linestring zm 10 02 20 01 5 0 7 0 23 73 21 92 6 5 7 1 30 10 40 23 6 9 7 2 1000 The ST_StartPoint function extracts the first point of each ST_LineString The first point in the list does not have a Z coordinate or a measure while the second point has both because the source linestring does SELECT gid ST_StartPoint 1nl Startpoint FROM startpoint_test gid 1 startpoint 1000 POINT 10 02 20 01 gid 2 startpoint 1000 POINT ZM 10 02 20 01 5 7 IBM Informix Spatial Data User s Guide See also The ST_EndPoint function on page 8 33 The ST_SymDifference function The ST_StartPoint function takes two ST_Geometry objects and returns a ST_Geometry object that is composed of the parts of the source objects that are not common to both Syntax ST_SymDifference gl ST_Geometry g2 ST_Geometry Return type ST_Geometry Example For a special report the county supervisor must determine the area of sensitive
249. nt function The ST_SymDifference function The SE_TotalSize function The ST_Touches function The SE_Trace function The ST_Transform function The ST_Union function A The SE_VertexAppend function The SE_VertexDelete function The SE_VertexUpdate function The ST_Within function The ST_WKBToSQL function The ST_WKTToSQL function The ST_X function The SE_Xmax and SE int functions vi IBM Informix Spatial Data User s Guide 8 68 8 69 8 70 8 71 8 71 8 72 8 72 8 73 8 74 8 75 8 75 8 76 8 77 8 78 8 78 8 79 8 80 8 81 8 82 8 82 8 83 8 83 8 85 8 85 8 86 8 86 8 87 8 88 8 89 8 89 8 90 8 90 8 91 8 92 8 93 8 94 8 94 8 95 8 96 8 97 8 97 8 98 8 98 8 99 8 100 8 101 8 102 8 103 8 104 8 104 8 105 8 106 8 108 8 109 8 109 8 109 8 110 8 111 8 112 8 113 8 113 The ST_Y function The SE_Ymax and SE Ymin f nctions The SE_Z function The ST_Zmax and ST Zmin functions Appendix A Load and unload a data The infoshp utility The loadshp utility The unloadshp utility Appendix B OGC well known text representation of spatial reference systems The text representation of a spatial system Linear units Angular units Geodetic spheroids Horizontal datums spheroid only Horizontal datums Prime meridians Projec
250. oaded into a newly created database table An error is returned if a table with the name specified by the 1 flag already exists The structure of the new table is derived from the table name and column name specified by the 1 command line option as well as from metadata stored in the shapefile s associated dbf file init The table specified by the 1 flag is first dropped and then spatial features are loaded into a newly created table of the same name sql The following SQL statements are displayed on the console and can be logged to a file e DROP TABLE e DELETE FROM geometry_columns e CREATE TABLE e INSERT INTO geometry_columns e CREATE UNIQUE INDEX USING btree e ALTER TABLE ADD CONSTRAINT PRIMARY KEY se_row_id e CREATE INDEX USING rtree e UPDATE STATISTICS The structure of the table to be loaded is derived from information specified by the 1 command line option and from metadata stored in the shapefile s associated dbf file containing feature attributes Command line switches You can use the loadshp command line switches to specify the following options b optional The first row in the shapefile to load c optional The number of rows to load before committing work and beginning a new transaction Defaults to 1000 rows If you are loading data into a database that does not have transaction logging enabled the commit interval determines how frequently information messages are d
251. ocateBetween function takes an ST_Geometry object and two measure locations and returns an ST_Geometry that represents the set of disconnected paths between the two measure locations Syntax SE_LocateBetween gl ST Geometry fm double precision tm double precision Chapter 8 Spatial functions 8 65 Return type ST_Geometry Example The locatebetween_test table is created with two columns the gid INTEGER column uniquely identifies each row while the g1 ST_MultiLineString stores the sample geometry CREATE TABLE locatebetween_ test gid integer gl ST Geometry The following INSERT statements insert two rows into the locatebetween_test table The first row is an ST_MultiLineString and the second is an ST_MultiPoint INSERT INTO locatebetween_test VALUES l ST_MLineFromText multilinestring m 10 29 19 23 5 23 82 20 29 6 30 19 18 47 7 45 98 20 74 8 23 82 20 29 6 30 98 23 98 7 42 92 25 98 8 1000 INSERT INTO locatebetween_test VALUES 2 ST_MPointFromText multipoint m 10 29 19 23 5 23 82 20 29 6 30 19 18 47 7 45 98 20 74 8 23 82 20 29 6 30 98 23 98 7 42 92 25 98 8 1000 In the query the SE_LocateBetween function locates measures lying between 6 5 and 7 5 inclusively The first row returns an ST_MultiLineString containing several linestrings The second row returns an ST_MultiPoint because the source data was ST_MultiPoint When the source data has a dimension of 0 point or multipoint an exact match
252. ointFromText function it is assigned the SRID value of 1 INSERT INTO srid_test VALUES ST_PointFromText point 10 01 50 76 1000 Js The ST_SRID function returns the spatial reference ID of the geometry just entered SELECT ST_SRID g1 FROM srid_test expression 1000 The SE_SRID_Authority function The SE_SRID_Authority function takes a spatial reference ID and returns the Authority Name and Authority SRID as an LVARCHAR string in the form AuthName SRID If the AuthName is null in the sde spatial_references table for a given spatial reference ID the srtext is returned Syntax SE_SRID_Authority SRID integer Return type LVARCHAR Example select SE SRID Authority srid from sde spatial_references expression UNKNOWN 0 expression EPSG 4135 expression EPSG 4267 Chapter 8 Spatial functions 8 101 expression EPSG 4269 expression EPSG 4326 expression UNKNOWN 0 expression UNKNOWN 0 expression UNKNOWN 0 expression AUTH NAME 1234 expression GEOGCS GCS_Old_Hawaiian DATUM D_OldHawaiian SPHEROID Clarke_1866 6378206 4 294 9786982 PRIMEM Greenwich 0 UNIT Degree 0 01745329 25199433 10 row s retrieved The ST_StartPoint function 8 102 The ST_StartPoint function returns the first point of a linestring Syntax ST_StartPoint Inl ST_LineString Return type ST_Point Example The startpoint_test table is created with the gid INTEGER column which u
253. ollowing INSERT statements insert two records into the closed_linestring table The first record is not a closed linestring while the second is INSERT INTO closed_linestring VALUES ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 J 8 54 IBM Informix Spatial Data User s Guide INSERT INTO closed_linestring VALUES ST_LineFromText linestring 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 s The query returns the results of the ST_IsClosed function The first row returns a 0 because the linestring is not closed while the second row returns a 1 because the linestring is closed SELECT ST_IsClosed 1n1 Is_it_closed FROM closed_linestring is_it_closed f t The closed_mlinestring table is created with a single ST_MultiLineString column CREATE TABLE closed_mlinestring mln1 ST_MultiLineString The following INSERT statements insert an ST_MultiLineString record that is not closed and another that is INSERT INTO closed_mlinestring VALUES ST_MLineFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 INSERT INTO closed_mlinestring VALUES ST_MLineFromText multilinestring 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 s The query lists the results of the ST_IsClosed function The first row returns 0 because the multilinestring is no
254. om a multipoint WKB representation ST_MLineFromWKB The function creates an ST_MultiLineString from a multilinestring WKB representation ST_MPolyFromWKB The function creates an ST_MultiPolygon from a multipolygon WKB representation ST_AsBinary The function converts an existing geometry value into well known binary representation Related reference ESRI shape representation 3 2 You can generate a geometry from an ESRI shape representation In addition to the two dimensional representation supported by the Open GIS well known binary representation the ESRI shape representation also supports optional Z coordinates and measures The following functions generate geometry from an ESRI shape SE_GeomFromShape The function creates an ST_Geometry from a shape of any geometry type SE_PointFromShape The function creates an ST_Point from a point shape SE_LineFromShape The function creates an ST_LineString from a polyline shape SE_PolyFromShape The function creates an ST_Polygon from a polygon shape SE_MPointFromShape The function creates an ST_MultiPoint from a multipoint shape SE_MLineFromShape The function creates an ST_MultiLineString from a multipart polyline shape SE_MPolyFromShape The function creates an ST_MultiPolygon from a multipart polygon shape IBM Informix Spatial Data User s Guide For all of these functions the first argument is the shape representation and the secon
255. ometric center as a point Syntax ST_Centroid pll ST_Polygon ST_Centroid mp11 ST_MultiPolygon Return type ST_Point Example The city GIS technician wants to display the building footprint multipolygons as single points in a building density graphic The building footprints are stored in the buildingfootprints table that was created with the following CREATE TABLE statement CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon The ST_Centroid function returns the centroid of each building footprint multipolygon SELECT building_id ST _Centroid footprint Centroid FROM buildingfootprints building_id 506 IBM Informix Spatial Data User s Guide centroid 1000 POINT 12 5 49 5 building_id 543 centroid 1000 POINT 32 51 5 building id 1208 centroid 1000 POINT 12 5 30 5 building_id 178 centroid 1000 POINT 32 28 5 The ST_Contains function The ST_Contains function takes two geometry objects and returns t TRUE if the first object completely contains the second otherwise it returns f FALSE Syntax ST_Contains gl geometry g2 geometry Return type BOOLEAN Example In the example below two tables are created buildingfootprints contains a city s building footprints and lots contains its lots The city engineer wants to ensure that all building footprints are completely inside their lots In both tables the ST_MultiPolygon data type stores th
256. on 1000 MULTIPOINT 9 55 23 75 10 02 20 01 11 92 25 64 15 36 30 1 1 geotype Mul tipolygon expression 1000 MULTILINESTRING 10 02 20 01 19 15 33 94 25 02 34 15 11 92 35 64 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 9 51 71 21 73 The SE_BoundingBox function 8 18 The SE_BoundingBox function returns a polygon which represents the spatial extent the minimum and maximum X and Y values of all the geometries in a spatial column of a table Important You must have an R tree index on the spatial column Syntax SE_BoundingBox tablename varchar 128 columnname varchar 128 Return type ST_Polygon Example The buildingfootprints table is created with the following statement The building _id column uniquely identifies the buildings the lot_id identifies the building s lot and the footprint multipolygon stores the building s geometry CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon After the table is populated create an R tree index on the footprint column CREATE INDEX footprint_ix ON buildingfootprints footprint ST_Geometry_ops USING RTREE Use the SE_BoundingBox function to obtain a polygon that defines the spatial extent of all the polygons in the table EXECUTE FUNCTION SE_BoundingBox buildingfootprints footprint expression 1000 POLYGON 7 22 38 22 38 55 7 55 7 22 Obtaining the Spatial Extent of a Funct
257. on and an optional spatial reference ID and returns a multipoint object A Point string can contain the elements of lt coordinates gt lt extrude gt lt tessellate gt and lt altitudeMode gt but they are ignored Chapter 8 Spatial functions 8 73 Syntax ST_MPointFromKML kmlstring lvarchar ST_MPointFromKML kmlstring lvarchar SRID integer Return type ST_MultiPoint Example EXECUTE FUNCTION ST_MPointFromKML lt MultiGeometry gt lt Point gt lt coordinates gt 122 365662 37 826988 0 lt coordinates gt lt Point gt lt Point gt lt coordinates gt 122 365038 37 82655 0 lt coordinates gt lt Point gt lt MultiGeometry gt 4 Output 4 MULTIPOINT Z 122 365662056 37 8269879529 0 122 36503794 37 8265500822 0 The SE_MPointFromShape function 8 74 The SE_MPointFromShape function takes a shape of type multipoint and a spatial reference ID to return an ST_MultiPoint Syntax SE_MPointFromShape sl lvarchar SRID integer Return type ST_MultiPoint Example The species_sitings table is created with three columns The species and genus columns uniquely identify each row while the sitings ST_MultiPoint stores the locations of the species sitings CREATE TABLE species_sitings species varchar 32 genus varchar 32 sitings ST_MultiPoint This code fragment populates the species_sitings table Create the SQL insert statement to populate the species_sitings table The question marks are
258. oordinates are the same and the envelope of a horizontal or vertical linestring is a linestring represented by the endpoints of the source linestring The ST_Envelope function takes an ST_Geometry and returns a ST_Geometry that represents the source ST_Geometry envelope Dimension A geometry can have a dimension of 0 1 or 2 0 The geometry has neither length or area 1 The geometry has a length 2 The geometry contains area The point and multipoint subclasses have a dimension of 0 Points represent zero dimensional features that can be modeled with a single coordinate while multipoints represent data that must be modeled as a cluster of unconnected coordinates The subclasses linestring and multilinestring have a dimension of 1 They store road segments branching river systems and any other features that are linear in nature Chapter 2 Spatial data types 2 3 Polygon and multipolygon subclasses have a dimension of 2 Forest stands parcels water bodies and other features whose perimeter encloses a definable area can be rendered by either the polygon or multipolygon data type Dimension is important not only as a property of the subclass but also plays a part in determining the spatial relationship of two features The dimension of the resulting feature or features determines whether the operation was successful The dimension of the features is examined to determine how they should be compared The ST_Dimension func
259. ot specify a directory the log file is created in the same directory as the shapefile you are loading p optional The IBM Informix password If you specify the p option you must also specify the u option s optional The IBM Informix server Defaults to the value of the INFORMIXSERVER environment variable t optional An integer indicating the type of shape to extract and write to the ESRI shapefile The possible values are Point PolyLine Polygon Multipoint a N e PointZ 10 PolyLineZ 11 PointZM 13 PolyLineZM 15 PolygonZM 18 MultiPointZM 19 PolygonZ 20 MultiPointZ 21 PointM 23 PolyLineM 25 PolygonM 28 MultiPointM If you do not specify the t option the type defaults to the type of the first shape retrieved from the database table u optional The IBM Informix user name If you specify the u option you must also specify the p option V Prints version information for this utility Appendix A Load and unload shapefile data A 7 w optional optional The SQL WHERE clause to qualify the data extracted from the table Enclose the WHERE clause in double quotation marks and enclose any string literals within the clause in single quotation marks Omit the keyword WHERE A 8 IBM Informix Spatial Data User s Guide Appendix B OGC well known text representation of spatial reference systems These topics explain how to represent a spatial reference system using a text string and p
260. ots table The ST_ WKBToSQL function converts WKB representations intoIBM Informix spatial geometry The entire INSERT statement is copied into the sq _stmt string The INSERT statement contains parameter markers to accept the lot_id data and the lot data dynamically Create the SQL insert statement to populate the lots table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO lots lot_id lot VALUES ST_WKBToSQL Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the lot_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM INPUT SQL_C_SLONG SQL_INTEGER 0 0 amp lot_id 0 amp pcbvaluel Bind the lot geometry to the second parameter pcbvalue2 lot_wkb_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_BINARY SQL_INFX_UDT_LVARCHAR lot_wkb_len 0 lot_wkb_buf lot_wkb_len amp pcbvalue2 Execute the insert statement rc SQLExecute hstmt Chapter 8 Spatial functions 8 111 The ST_WKTToSQL function 8 112 The ST_WKTToSQL function constructs an ST_Geometry given its well known text representation The SRID of the ST_Geometry is 0 Syntax ST_WKTToSQL WKT lvarchar Return type ST_Geometry Example The following CREATE TABLE statement creates the geometry_test ta
261. own text representation remove the quotations and precede the text description with the SRID separated by a space For example the well known text representation of a point in the ST_PointFromText function ST_PointFromText Point zm 10 98 29 91 10 2 9 1 1 converts to 1 ST Point zm 10 98 29 91 10 2 9 1 You can write the modified text string into a file and separate it from other column values by the standard delimiter C 4 IBM Informix Spatial Data User s Guide Appendix D OGC well known binary representation of geometry The well known binary representation for OGC geometry WKBGeometry provides a portable representation of a geometry value as a contiguous stream of bytes It permits geometry values to be exchanged between a client application and an SQL database in binary form The well known binary representation for geometry is obtained by serializing a geometry instance as a sequence of numeric types drawn from the set Unsigned Integer Double and then serializing each numeric type as a sequence of bytes using one of two well defined standard binary representations for numeric types NDR XDR The specific binary encoding used for a geometry byte stream is described by a one byte tag that precedes the serialized bytes The only difference between the two encodings of geometry is byte order The XDR encoding is big endian while the NDR encoding is little endian Numeric type definitions An unsigned integer
262. pcbvalue3 Execute the insert statement rc SQLExecute hstmt The SE_Mmax and SE_Mmin functions The SE_Mmax and SE_Mmin functions return the maximum and minimum measure values of a geometry Syntax SE_Mmax ST_Geometry SE_Mmin ST_Geometry Return type DOUBLE PRECISION The ST_MPointFromGML function 8 72 The ST_MPointFromGML function takes a GML2 or GML3 string representation of an ST_MultiPoint and an optional spatial reference ID and returns a polygon object Syntax ST_MPointFromGML gmlstring lvarchar ST_MPointFromGML gmlstring lvarchar SRID integer IBM Informix Spatial Data User s Guide Return type ST_MultiPoint Example The gml_pointtest table is created with the SMALLINT column gid and the ST_MultiPoint column mpt1 CREATE TABLE gml_pointtest gid smallint mptl ST _MultiPoint INSERT INTO gml_pointtest VALUES 1 ST_MPointFromGML lt gml MultiPoint gt lt gm PointMember gt lt gm Point gt lt gml pos gt 110 45 45 256 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gml PointMember gt lt gml Point gt lt gml pos gt 99 45 33 256 lt gml pos gt lt gml Point gt lt gml PointMember gt lt gm l MultiPoint gt 4 INSERT INTO gml_pointtest VALUES 2 ST_MPointFromGML lt gm1 MultiPoint srsName EPSG 4326 srsDimension 3 gt lt gml PointMember gt lt gml Point srsName EPSG 4326 srsDimension 3 gt lt gml pos gt 110 449999933
263. penGIS Abstract Specification These assertions imply the following Linear rings Rings are simple and closed which means that linear rings may not self intersect Polygons No two linear rings in the boundary of a polygon may cross each other The linear rings in the boundary of a polygon may intersect at most at a single point but only as a tangent Multipolygons The interiors of two polygons that are elements of a multipolygon may not intersect The boundaries of any two polygons that are elements of a multipolygon may touch at only a finite number of points IBM Informix Spatial Data User s Guide Appendix E ESRI shape representation The ESRI shape representation is an industry standard format that is used in ESRI shape files You can use the SE_AsShape function to retrieve geometries from a table in shape format You can insert shape format data into database tables by and other similar functions All functions are described in detail in using the SE_GeomFromShape SE_PointFromShape SE_PolyFromShape Spatial functions on page 8 1 These topics provide background information about the ESRI shape representation Related reference ESRI shape representation on page 3 2 Shape type values A shape type of 0 indicates a null shape with no geometric data for the shape Value Shape type 0 Null Shape 1 Point 3 PolyLine 5 Polygon 8 MultiPoint 9 PointZ 10 PolyLineZ 11 PointZM
264. ple nonclosed ST_LineString 2 is a nonsimple nonclosed ST_LineString 3 is a closed simple ST_LineString and therefore is a ring 4 is a closed nonsimple ST_LineString it is not a ring VW OF 1 2 3 4 Figure 2 2 Examples of ST_LineString objects Functions The following functions operate on ST_LineString ST_StartPoint The function returns the linestring s first point Chapter 2 Spatial data types 2 5 ST_EndPoint The function returns the linestring s last point ST_PointN The function takes an ST_LineString and an index to nth point and returns that point ST_Length The function returns the linestring s length as a double precision number ST_NumPoints The function returns the number of points in the linestring s sequence as an integer ST_IsRing The function returns t TRUE if the ST_LineString is a ring and f FALSE otherwise ST_IsClosed The function returns t TRUE if the ST_LineString is closed and f FALSE otherwise ST_Polygon The function creates a polygon from an ST_LineString that is a ring ST_Polygon data type 2 6 The ST_Polygon data type is a two dimensional surface stored as a sequence of points defining its exterior bounding ring and 0 or more interior rings Most often ST_Polygon defines parcels of land water bodies and other features having spatial extent Properties The ST_Polygon is always simple The exterior and any interior rings define the bo
265. ponse Compare the projection string with the valid projection strings listed in Appendix B OGC well known text representation of spatial reference USE42 Nearest neighbor queries are not supported by the current version of the server Explanation Nearest neighbor queries are supported by IBM Informix Version 9 3 and later PARAM1 value must be less than PARAM2 value USE43 Explanation When executing the SE_CreateSrid function xmin must be less than xmax and ymin must be less than ymax USE44 Unknown OGIS WKB byte order byte encountered in FUNCTION Explanation An unrecognized OpenGIS well known binary byte order byte was encountered This is the first byte of the geometry data input byte stream Valid values are 0x00 big endian and 0x01 little endian USE45 OGIS WKB geometry collection type is not supported Explanation The OpenGIS collection type 7 is not supported by this version of the Spatial DataBlade module USE46 Incompatible coordinate reference systems in function FUNCTION Explanation This error can occur when you attempt to transform geometries using the ST_Transform function The only allowable transformations in this version of the Spatial DataBlade module are Between two UNKNOWN coordinate systems that is the srtext column in the spatial_references table for both SRIDs is UNKNOWN e Between a projected coordinate system and an unproje
266. pplication s draw_polygon function for display Create the SQL expression sprintf sql_stmt SELECT ST_AsBinary zone FROM sensitive_areas WHERE SE_EnvelopesIntersect zone ST PolyFromWKB d srid Prepare the SQL statement SQLPrepare hstmt UCHAR sql_stmt SQL_NTS Bind the query shape parameter pcbvaluel query_wkb_len SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL_C_ BINARY SQL_INFX_UDT_LVARCHAR query_wkb_len 0 query_wkb_ buf query_wkb_len amp pcbvaluel Execute the query rc SQLExecute hstmt Assign the results of the query the buildingfootprint polygons to the fetched binary variable SQLBindCol hstmt 1 SQL_C BINARY fetched_wkb_buf 10000 amp fetched_wkb_len Fetch each polygon within the display window and display it while 1 rc SQLFetch hstmt if rc SQL_NO_DATA_FOUND break else returncode_check NULL hstmt rc SQLFetch draw_polygon fetched_wkb_buf Close the result set cursor SQLCloseCursor hstmt The SE_AsGML function The SE_AsGML function returns the Geography Markup Language GML representation of an ST_Geometry spatial type 8 10 IBM Informix Spatial Data User s Guide Typically you use the SE_LAsGML function to retrieve the GML representation of a spatial primitive from the server and send it to a client as in SELECT SE_AsGML geomcol FROM mytable The return type of the SE_
267. problems with SE_Metadatalnit In some rare circumstances you might need to run the SE_MetadataInit function to resolve problems Run the SE_MetadataInit function to resolve the following problems e The metadata lohandle file is corrupted or missing or cannot be created e The metadata smart large object is corrupted or missing e The metadata memory cache is corrupted or locked The SE_MetadataInit function cannot be run in parallel Related reference The SE_MetadataInit function on page 8 67 Execute parallel queries To run queries in parallel you must use the IBM Informix parallel database query PDQ feature To take full advantage of the performance enhancement PDQ provides you need to use fragmented tables table fragmentation allows you to store parts of a table on different disks Copyright IBM Corp 2001 2010 5 1 See the IBM Informix Performance Guide for information about these topics The IBM Informix Performance Guide contains topics that describe how the database server executes queries in parallel and how you can manage running queries in parallel it also includes topics that describe how to work with fragmented tables 5 2 IBM Informix Spatial Data User s Guide Chapter 6 Estimate your spatial data The total amount of space you need for spatial data is equal to the size of spatial tables plus the size of the spatial indexes The table size approximations discussed here should b
268. query_shape_len 0 query_shape_ buf query_shape_len amp pcbvaluel Execute the query rc SQLExecute hstmt Assign the results of the query the Zone polygons to the fetched_shape_buf variable SQLBindCol hstmt 1 SQL_C_BINARY fetched_shape_ buf 10000 amp fetched_shape_len Fetch each polygon within the display window and display it while SQL_SUCCESS rc SQLFetch hstmt draw_polygon fetched_shape_buf The ST_AsText function The ST_AsText function takes an ST_Geometry object and returns its well known text representation The return type of ST_AsText is defined as ST_Geometry to allow spatial objects greater than 2 kilobytes to be retrieved by a client application Chapter 8 Spatial functions 8 15 Typically you use ST_AsText to retrieve spatial data from the server and send it to a client as in SELECT ST_AsText geomcol FROM mytable IBM Informix automatically casts the output of the ST_AsText function to the proper data type for transmission to the client You can write user defined routines UDRs in C or SPL to extend the functionality of the existing spatial data type functions You can use ST_AsText to convert an ST_Geometry to its well known text representation If you pass the output of ST_AsText to another UDR whose function signature requires an LVARCHAR input you should explicitly cast the return type of ST_AsText to LVARCHAR as in EXECUTE FUNCTI
269. r the boundaries of either geometry intersect Table 7 4 Pattern matrix for the ST_Disjoint function b Interior Boundary Exterior Interior F F j a Boundary F F Exterior Related reference The ST_Disjoint function on page 8 30 The ST_Intersects function The ST_Intersects function returns TRUE if the conditions of any of the following pattern matrices returns TRUE The ST_Intersects function returns TRUE if the interiors of both geometries intersect Chapter 7 Determine spatial relationships and transform geometries 7 17 b Interior Boundary Exterior Interior T a Boundary 7 r j Exterior i The ST_Intersects function returns TRUE if the boundary of the first geometry intersects the boundary of the second geometry b Interior Boundary Exterior Interior T a Boundary i Exterior R 7 The ST_Intersects function returns TRUE if the boundary of the first geometry intersects the interior of the second b Interior Boundary Exterior Interior i j a Boundary T S Exterior i ig i The ST_Intersects function returns TRUE if the boundaries of either geometry intersect b Interior Boundary Exterior Interior i a Boundary j T i Exterior i i Related reference The ST_Intersects function on page 8 52 The ST_Touches function The pattern matrices show us that the ST_Touches function r
270. rd FROM z_test gid z_coord 1 2 5 000000000000 The ST_Zmax and ST_Zmin functions The ST_Zmax and ST_Zmin functions return the maximum and minimum Z coordinates of a geometry Syntax ST_Zmax ST_Geometry ST_Zmin ST_Geometry Return type DOUBLE PRECISION Chapter 8 Spatial functions 8 115 8 116 IBM Informix Spatial Data User s Guide Appendix A Load and unload shapefile data Use the infoshp loadshp and unloadshp utilities for working with spatial data contained in ESRI shapefiles The executable files for the utilities are located in the INFORMIXDIR extend spatial version bin directory e The infoshp utility is useful for gathering information from ESRI shapefiles when you are preparing to load the shapefiles into a database e The loadshp utility loads spatial data from an ESRI shapefile into the database e The unloadshp utility copies data from the database to an ESRI shapefile You can leave them in this directory or you can copy them to INFORMIXDIR bin If you leave them here you may want to add INFORMIXDIR extend spatial version bin to your PATH environment variable If you copy the files to INFORMIXDIR bin you may not need to change your PATH environment variable if INFORMIXDIR bin is already included in the variable definition Important The loadshp utility does not add information to ESRI system tables such as the layers table Therefore data loaded with the loadshp utility is
271. rdinates gt 10 02 20 01 lt coordinates gt lt Point gt 4 INSERT INTO geometry_test VALUES 2 ST_GeomFromKML lt LineString gt lt coordinates gt 10 01 20 01 20 01 30 01 30 01 40 01 lt coordinates gt lt LineString gt 4 The SE_GeomFromShape function 8 46 The SE_GeomFromShape function takes a shape and a spatial reference ID and returns a geometry object Syntax SE_GeomFromShape sl lvarchar SRID integer Return type ST_Geometry Example The following C code fragment contains ODBC functions included with the spatial data type functions that insert data into the lots table The lots table was created with two columns the lot_id which uniquely identifies each lot and the lot polygon column which contains the geometry of each lot CREATE TABLE lots lot_id integer lot ST_MultiPolygon The SE_GeomFromShape function converts shapes into an IBM Informix spatial geometry The entire INSERT statement is copied into shp_sql The INSERT statement contains parameter markers to accept the lot_id and lot data dynamically Create the SQL insert statement to populate the lots table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO lots lot_id lot VALUES SE_GeomFromShape d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bi
272. rding to their proximity to one another The sort key is computed by applying the Hilbert space filling curve algorithm to the center point of an object s bounding box Syntax SE_SpatialKey g1 ST Geometry Return type A numeric sort key as an INT8 Chapter 8 Spatial functions 8 99 Example Create and populate a cities table containing the names and locations of world cities CREATE TABLE cities name varchar 255 locn ST Point LOAD FROM cities load INSERT INTO cities Create a clustered functional B tree index This rearranges the table data placing it in spatial key sort order cept Ree nde or pee provides information about using indexes in particular R tree indexes For example CREATE CLUSTER INDEX cbt_idx ON cities SE_SpatialKey locn Create an R tree index with the NO_SORT option CREATE INDEX locn_idx ON cities locn ST_Geometry_ops USING RTREE BOTTOM _UP_BUILD yes NO SORT yes Drop the B tree index it is no longer needed DROP INDEX cbt_idx Related concepts Bottom up versus top down index builds on page 4 3 Related reference Syntax for creating an R tree index on page 4 1 The ST_SRID function The ST_SRID function takes an ST_Geometry object and returns its spatial reference ID Syntax ST_SRID g1 ST Geometry Return type INTEGER Example During the installation of the IBM Informix Spatial DataBlade Module the spatial_references table is created by this C
273. re simple if they obey all topological rules imposed on the subclass and nonsimple if they bend a few rules e ST_LineString is simple if it does not intersect its interior 2 2 IBM Informix Spatial Data User s Guide e ST_MultiPoint is simple if none of its elements occupy the same coordinate space e ST_MultiLineString is simple if none of its element s interiors intersect The ST_IsSimple function takes an ST_Geometry and returns t TRUE if the ST_Geometry is simple and f FALSE otherwise Empty or not empty A geometry is empty if it does not have any points An empty geometry has a NULL envelope boundary interior and exterior An empty geometry is always simple and can have Z coordinates or measures Empty linestrings and multilinestrings have a 0 length Empty polygons and multipolygons have 0 area The ST_IsEmpty function takes an ST_Geometry and returns t TRUE if the ST_Geometry is empty and f FALSE otherwise Number of points A geometry can have zero or more points A geometry is considered empty if it has zero points The ST_Point subclass is the only geometry that is restricted to zero or one point all other subclasses can have zero or more Envelope The envelope of a geometry is the bounding geometry formed by the minimum and maximum X Y coordinates The envelopes of most geometries form a boundary rectangle however the envelope of a point is the point itself since its minimum and maximum c
274. re that the underlying geographic coordinate system in this case NAD 83 is the same this version of the IBM Informix Spatial DataBlade Module does not perform datum conversions INSERT INTO spatial_references srid description falsex falsey xyunits falsez zunits falsem munits srtext VALUES 1005 UTM zone 12N NAD 83 datum 336000 4760000 1000 0 1000 0 1000 SE_CreateSrtext 26912 Transform the data to a projected coordinate system on an as needed basis SELECT id ST_Transform locn 1005 as utm FROM airports id BTM utm 1005 POINT 383951 152 5090115 666 id BZN utm 1005 POINT 488105 331 5069271 419 id COD utm 1005 POINT 657049 762 4931552 365 id JAC utm 1005 POINT 521167 881 4828291 447 id IDA utm 1005 POINT 413500 979 4818519 081 Related reference The ST_Union function The ST_Union function returns an ST_Geometry object that is the union of two source objects Syntax ST_Union gl ST_Geometry g2 ST_Geometry Return type ST_Geometry Example The sensitive_areas table contains several columns that describe the threatened institutions in addition to the zone column which stores the institutions ST_Polygon geometries CREATE TABLE sensitive_areas id integer name varchar 128 size float type varchar 10 zone ST Polygon 8 108 IBM Informix Spatial Data User s Guide The hazardous_sites table stores the identity of the sites in the site_id and name columns w
275. re the query to get the length of an interior ring For efficiency we only prepare this query once sprintf sql_stmt SELECT ST _Length ST_InteriorRingN land FROM islands WHERE id rc SQLPrepare lake_cursor UCHAR sql_stmt SQL_NTS Bind the lake_number to the first parameter pcbvaluel 0 rc SQLBindParameter lake cursor 1 SQL_PARAM INPUT SQL_C_LONG SQL_INTEGER 0 0 amp lake_number 0 amp pcbvaluel Bind the island_id to the second parameter pcbvalue2 0 rc SQLBindParameter lake_cursor 2 SQL_PARAM INPUT SQL_C_LONG SQL_INTEGER 0 0 amp island_id 0 amp pcbvalue2 IBM Informix Spatial Data User s Guide Bind the result of the ST_Length function to lake perimeter rc SQLBindCol lake_cursor 1 SQL_C_SLONG amp lake_perimeter 0 amp length_ind Outer loop x get the island ids and the number of lakes interior rings while 1 Fetch an island rc SQLFetch island_cursor if rc SQL_NO_DATA break else returncode check NULL hstmt rc SQLFetch Inner loop for this island get the perimeter of all its lakes interior rings for total_perimeter 0 lake_number 1 lake_number lt num_lakes lake_number rc SQLExecute lake_cursor rc SQLFetch lake_cursor total_perimeter lake_perimeter SQLFreeStmt lake_cursor SQL_CLOSE Display the island ID and the total perimeter of its lakes
276. reated with two columns gid which uniquely identifies the row and the pt1 point column CREATE TABLE x_test gid integer pt1 ST Point The following INSERT statements insert two rows One is a point without a Z coordinate or a measure The other column has both a Z coordinate and a measure INSERT INTO x_test VALUES l ST_PointFromText point 10 02 20 01 1000 s INSERT INTO x_test VALUES ST_PointFromText point zm 10 02 20 01 5 0 7 0 1000 The query retrieves the values in the gid column and the DOUBLE PRECISION X coordinate of the points SELECT gid ST_X pt1 x_coord FROM x_test gid x_coord 1 10 02000000000 2 10 02000000000 The SE_Xmax and SE_Xmin functions The SE_Xmax and SE_Xmin functions return the maximum and minimum X coordinates of a geometry Syntax ST_Xmax ST_Geometry ST_Xmin ST_Geometry Return type DOUBLE PRECISION Chapter 8 Spatial functions 8 113 The ST_Y function The ST_Y function returns the Y coordinate of a point Syntax ST_Y p1 ST_Point Return type DOUBLE PRECISION Example The y_test table is created with two columns gid which uniquely identifies the row and the pt1 point column CREATE TABLE y_ test gid integer pt1 ST Point The following INSERT statements insert two rows One is a point without a Z coordinate or a measure The other has both a Z coordinate and a measure INSERT INTO y_test VALUES ST_PointFromText
277. red at the leaf level of the R tree This is the default if the DBSPACETEMP parameter in your onconfig file is not defined BOTTOM_UP_BUILD no BOUNDING_BOX_INDEX yes NO_SORT no Creates a more compact index from the top down Only the bounding boxes of each object are stored at the leaf level of the R tree No temporary dbspace is required BOTTOM_UP_BUILD yes BOUNDING_BOX_INDEX no NO_SORT no Creates an index by sorting the spatial data and then building the R tree from the bottom up This is generally faster than building an index from the top down This is the default if you have a temporary dbspace and it is specified by the DBSPACETEMP parameter in your onconfig file BOTTOM_UP_BUILD yes BOUNDING_BOX_INDEX no NO_SORT yes Creates an index in less time e Does not require a temporary dbspace e Spatial data must be presorted either by loading the data in a predetermined order or by creating a clustered functional B tree index by using the SE_SpatialKey function IBM Informix Spatial Data User s Guide Table 4 1 Parameters of the CREATE INDEX statement for spatial data continued Parameters clause of CREATE INDEX statement Description BOTTOM_UP_BUILD yes Creates a more compact index from the BOUNDING_BOX_INDEX yes bottom up which is faster than building from NO_SORT no the top down e This is the default if you have a temporary dbspace and it is specified by the DBSPA
278. reference ID and returns a multipart polyline object Syntax ST_MLineFromGML gmlstring lvarchar ST_MLineFromGML gmlstring lvarchar SRID integer Return type ST_MultiLineString Example The gml_linetest table is created with the SMALLINT column gid and the ST_MultiLineString column In1 CREATE TABLE gml_linetest gid smallint 1n1 ST_MultiLineString INSERT INTO gml_linetest VALUES 1 ST_MLineFromGML lt gml MultiLineString gt lt gm LineStringMember gt lt gml LineString gt lt gml posList gt 110 45 45 256 109 48 46 46 109 86 43 84 lt gml posList gt lt gml LineString gt lt gml LineStringMember gt lt gml LineStringMember gt lt gml LineString gt lt gml posList gt 99 45 33 256 99 48 36 46 99 86 33 84 lt gml posList gt lt gml LineString gt lt gml LineStringMember gt lt gml MultiLineString gt 4 INSERT INTO gml_linetest VALUES 2 ST_MLineFromGML lt gm MultiLineString srsName EPSG 4326 srsDimension 3 gt lt gml LineStringMember gt lt gml LineString srsName EPSG 4326 srsDimension 3 gt lt gml posList dimension 3 gt 110 449999933 45 2559999343 10 109 47999994 46 4600005499 10 109 86000008 43 8400000201 20 lt gml posList gt lt gml LineString gt lt gml LineStringMember gt lt gml LineStringMember gt lt gml LineString srsName EPSG 4326 srsDimension 3 gt lt gml posList dimension 3 gt 99 45 33 256 10 99 48 36 46 10 99 86 33 84 20 lt gml posList gt lt gml
279. rence ID A polyline with only one part is appropriate as an ST_LineString see The SE_LineFromShape function on page 5 6 62 and a polyline with multiple parts is appropriate as an ST_MultiLineString Syntax SE_MLineFromShape sl lvarchar SRID integer Return type ST_MultiLineString Example The waterways table is created with the ID and name columns that identify each stream and river system stored in the table The water column is an ST_MultiLineString because the river and stream systems are often an aggregate of several linestrings CREATE TABLE waterways id integer name varchar 128 water ST_MultiLineString This code fragment populates the waterways table with a unique ID a name and a water multilinestring Create the SQL insert statement to populate the waterways table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO waterways id name water VALUES ST_MlineFromShape d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL _C_SLONG SQL_INTEGER 0 0 amp id 0 amp pcbvaluel Bind the name to the second parameter pcbvalue2 name_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C_CHAR SQL_CHA
280. returns an ST_Geometry unction on page 8 4 p En SI Takes a KML LineString string representation The ST_LineFromKML and returns an ST_LineString function on page 8 61 Takes a KML MultiGeometry string The ST_MLineFromKML representation and returns an function on page 8 69 ST_MultiLineString Takes a KML MultiGeometry and Point The ST_MPointFromKML iss combination string representation and returns __ function on page 8 7 an ST_MultiPoint Takes a KML MultiGeometry and Polygon The ST_MPolyFromKM combination string representation and returns unction on page 8 7 an ST_MultiPolygon al N Takes a KML Point string representation and The ST_PointFromKML returns an ST_Point unction on page 8 8 Co hl Ke Takes a KML Polygon string representation and The ST_PolyFromKML returns an ST_Polygon unction on page 8 9 rm Chapter 8 Spatial functions 8 3 Table 8 1 Spatial functions by task type continued Function task type Description Function name Convert a geometry to an external format Returns the well known text representation of a The ST_AsText function on geometry object Returns the well known binary representation of a geometry object The ST_AsBinary function on Returns the ESRI shape representation of a geometry object Returns the GML representation of a geometry object Retu
281. rientation Dirty polygons occur when the rings that define holes in the polygon also go clockwise which causes overlapping interiors A sample polygon instance The following figure shows a polygon with one hole and a total of eight vertices vi v5 v4 v8 v6 v2 v7 v3 Figure E 1 A sample polygon For this example NumParts equals 2 and NumPoints equals 10 Note that the order of the points for the doughnut hole polygon is reversed below 0 1 2 3 4 5 6 ti 8 g Points v2 v3 v4 v4 v5 vB v v6 The following table shows Polygon byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 5 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer NumParts Little endian Byte X Points Points Point NumPoints Little endian Tip X 44 4 NumParts Measured shape types in XY space These topics describe shapes with X and Y coordinates that also have measure values E 4 IBM Informix Spatial Data User s Guide PointM A PointM consists of a pair of double precision coordinates in the order X Y plus a measure M The following table shows PointM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 21 Integer 1 Little endian Byte 4 X X Double 1 Little endian Byte 12 Y Y Double ji Little endian Byte 20 M M Dou
282. ries However this function does not account for dbspace and sbspace overhead so cannot be used to obtain an exact total IBM Informix Spatial Data User s Guide Syntax SE_InRowSize ST_Geometry Return type INTEGER See also The SE_OutOfRowSize function on page 8 83 The SE_TotalSize function on page 8 104 The ST_InteriorRingN function The ST_InteriorRingN function returns the mth interior ring of a polygon as an ST_LineString The order of the rings cannot be predefined since the rings are organized according to the rules defined by the internal geometry verification routines and not by geometric orientation Syntax ST_InteriorRingN pll1 ST Polygon index integer Return type ST_LineString Example An ornithologist studying the bird population on several South Sea islands knows that the feeding zone of this passive species is restricted to the seashore Some of the islands are so large they have several lakes on them The shorelines of the lakes are inhabited exclusively by another more aggressive species The ornithologist knows that if the perimeter of the ponds on each island exceeds a certain threshold the aggressive species will become so numerous that it will threaten the passive seashore species Therefore the ornithologist requires the aggregated perimeter of the interior rings of the islands The following figure shows the exterior rings of the islands that represent the ecological inter
283. rify that the index is correctly built The spatial operator class ST_Geometry_Ops How spatial operators use R tree indexes Chapter 5 Run parallel queries Parallel query execution infrastructure Resolve problems with SE Juno Execute parallel queries a Chapter 6 Estimate your spatial data Estimating the storage space for the table Estimate the size of the spatial column Estimate the size of non spatial columns Estimate dbspace overhead requirements Estimating the smart large object storage space Estimating the size of spatial indexes Chapter 7 Determine spatial relationships and transform geometries Functions that determine spatial relationships The ST_Equals function The ST_Disjoint function The ST_Intersects function The ST_Touches function The ST_Overlaps function The ST_Crosses function The ST_Within function The ST_Contains function Functions that produce a new geometry The ST_Intersection function The ST_Difference function The ST_Union function The ST_SymDifference function The SE_Dissolve function Functions that transform geometries The ST_Buffer function The SE_LocateAlong function The SE_LocateBetween function The ST_ConvexHull function The SE_Generalize function The Dimensionally Extended 9 Intersection Model The ST_Equals function The ST_Disjoint function The ST_Intersects function The ST_Touches function The ST_Overlaps funct
284. ription OGC well known text string 106002 Fischer 1960 DATUM D_Fischer_1960 SPHEROID Fischer_1960 6378166 298 3 106003 Fischer 1968 DATUM D_Fischer_1968 SPHEROID Fischer_1968 6378150 298 3 106004 Fischer modified DATUM D_Fischer_Modified SPHEROID Fischer_Modified 6378155 298 3 106005 Hough 1960 DATUM D_Hough_1960 SPHEROID Hough_1960 6378270 297 106006 Everest modified DATUM D_Everest_Modified_1969 1969 SPHEROID Everest_Modified_1969 6377295 664 300 8017 106007 Walbeck DATUM D_Walbeck SPHEROID Walbeck 6376896 302 78 106008 Authalic sphere DATUM D_Sphere_ARC_INFO SPHEROID Sphere_ARC_INFO 6370997 0 ARC INFO Horizontal datums IBM Informix spatial data types support many horizontal datums The following table lists a representative sample of the horizontal datums supported by the IBM Informix spatial data types For a complete list of supported horizontal datums see the file INFORMIXDIR extend spatial version include pedef h Table B 5 Horizontal datums Factory ID Description OGC well known text string 6201 Adindan DATUM D_Adindan SPHEROID Clarke_1880_RGS 6378249 145 293 465 6205 Afgooye DATUM D_Afgooye SPHEROID Krasovsky_1940 6378245 298 3 6206 Agadez DATUM D_Agadez SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6202 Australian Geodetic DATUM D_Australian_1966 SPHEROID Australian 6378160 298 25 Datum 1966 6203 Aus
285. rns the GML3 Envelope element of an ST_Envelope object The SE_AsShape function on The SE_AsGML function on page 8 10 or The ST_AsGML function on page 8 11 The ST_EnvelopeAsGML function on page 8 35 Returns the KML representation of a geometry object The ST_AsKML function on page 8 13 or The SE_AsKML function on page 8 12 Returns the KML LatLonBox of an ST_Envelope object The SE_EnvelopeAsKML unction on page 8 36 En Manipulate the ST_Point data type Creates an ST_Point data type from an X and Y coordinate n E oO Wn 4 rg O 5 Eg g 5 Q 5 5 page 8 8 Returns the X coordinate of a point E g oO wn m x gt ES a T O 5 5 gej D ya e Returns the Y coordinate of a point gt oO 4 ST_Y function on pag Returns the Z coordinate of a point The SE_Z function on page Returns the measure value of a point The SE_M function on page Manipulate the ST_LineString and ST_MultiLineString data types Returns the first point The ST_StartPoint function on 9 o Q oO oo 1 oO N Returns the midpoint n E oO ep mi z Q K Q 3 i a T 5 5 page 8 6 Returns the last point The ST_EndPoint function on page 8 3 Returns the nth point The ST_Po
286. roducts can support many languages cultures and code sets All the information related to character set collation and representation of numeric data currency date and time that is used by a language within a given territory and encoding is brought together in a single environment called a GLS Global Language Support locale The IBM Informix OLE DB Provider follows the ISO string formats for date time and money as defined by the Microsoft OLE DB standards You can override that default by setting an Informix environment variable or registry entry such as DBDATE If you use Simple Network Management Protocol SNMP in your IBM Informix environment note that the protocols GNMPv1 and SNMPv2 recognize only English code sets For more information see the topic about GLS and SNMP in the IBM Informix SNMP Subagent Guide The examples in this publication are written with the assumption that you are using one of these locales en_us 8859 1 ISO 8859 1 on UNIX platforms or en_us 1252 Microsoft 1252 in Windows environments These locales support U S English format conventions for displaying and entering date time number and currency values They also support the ISO 8859 1 code set on UNIX and Linux or the Microsoft 1252 code set on Windows which includes the ASCII code set plus many 8 bit characters such as and Copyright IBM Corp 2001 2010 ix You can specify another locale if you plan to use characters from oth
287. rovides information about supported units of measure spheroids datums prime meridians and projections The information provided in these topics is primarily intended for use with the ST_Transform function Related reference The ST_Transform function on page 8 106 The text representation of a spatial system The well known text representation of spatial reference systems provides a standard textual representation for spatial reference system information The definitions of the well known text representation are modeled after the POSC EPSG coordinate system data model A spatial reference system also referred to as a coordinate system is a geographic latitude longitude a projected X Y or a geocentric X Y Z coordinate system A coordinate system is composed of several objects Each object is defined by an uppercase keyword for example DATUM or UNIT followed by the defining comma delimited parameters of the object in brackets Some objects are composed of other objects Implementations are free to substitute standard brackets for square brackets and should be prepared to read both forms of brackets The Extended Backus Naur Form EBNF definition for the string representation of a coordinate system is as follows using square brackets lt coordinate system gt lt projected cs gt lt geographic cs gt lt geocentric cs gt lt projected cs gt PROJCS lt name gt lt geographic cs gt
288. ry has Z coordinates or measures Leave this argument blank if the geometry has neither otherwise set the coordinate type to Z for geometries containing Z coordinates M for geometries with measures and ZM for geometries that have both The coordinate list defines the double precision vertices of the geometry Coordinate lists are comma delimited and enclosed by parentheses Geometries having multiple components require sets of parentheses to enclose each component part If the geometry is empty the EMPTY keyword replaces the coordinates C 2 IBM Informix Spatial Data User s Guide The following examples provide a complete list of all possible permutations of the text description portion of the text representation Geometry type Text description Comment ST_Point point empty Empty point ST_Point point z empty Empty point with Z coordinate ST_Point point m empty Empty point with measure ST_Point point zm empty Empty point with Z coordinate and measure ST_Point point 10 05 10 28 Point ST_Point point z 10 05 10 28 2 51 Point with Z coordinate ST_Point point m 10 05 10 28 4 72 Point with measure ST_Point point zm 10 05 10 28 2 51 4 72 Point with Z coordinate and measure ST_LineString linestring empty Empty linestring ST_LineString linestring z empty Empty linestring with Z coordinates ST_LineString linestring m empty Empty linestring with measures ST_LineString lines
289. s ST_LineString ST_LineString Empty ST_Polygon ST_Polygon Empty Oa ST_Polygon ST_Polygon ST_Polygon Figure 7 10 The ST_Difference function Related reference The ST_Difference function on page 8 28 The ST_Union function The ST_Union function returns the union set of two geometries the Boolean logical OR of space The source geometries must have the same dimension ST_Union returns the result as an ST_GeomCollection ST_MultiPoint ST_MultiLineString or ST_MultiPolygon Chapter 7 Determine spatial relationships and transform geometries 7 9 J ST_Point ST_Point ST_MultiPoint ST_Point ST_Point ST_MultiPoint J J J gt 0 e gt e J ST_Point ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_MultiPoint fe a VAN VY ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_LineString ST_LineString ST_MultiLineString ee F CIO ST_LineString ST_LineString ST_MultiLineString ST_Polygon ST_Polygon ST_MultiPolygon s ST_Polygon ST_Polygon ST_MultiPolygon Figure 7 11 The union set of two geometries Related reference The ST_Union function on page 8 108 The ST_SymDifference function The ST_StartPoint function returns the symmetric difference of two geometries the logical XOR of space the portions of the source geometries that are not part of the intersection set The source geometries must have the same dimension If the geometries are equal th
290. s The possible pattern values are T An intersection must exist dim 0 1 or 2 F An intersection must not exist dim 1 It does not matter if an intersection exists or not dim 1 0 1 or 2 0 An intersection must exist and its maximum dimension must be 0 dim 0 1 An intersection must exist and its maximum dimension must be 1 dim 1 2 An intersection must exist and its maximum dimension must be 2 dim 2 For example the pattern matrix of the ST_Within function for geometry combinations has the following form IBM Informix Spatial Data User s Guide Table 7 2 Pattern matrix of the ST_Within function b Interior Boundary Exterior Interior T a Boundary i ig Exterior s Simply put the ST_Within function returns TRUE when the interiors of both geometries intersect and the interior and boundary of geometry a does not intersect the exterior of geometry b All other conditions do not matter The ST_Equals function The DE 9IM pattern matrix for the ST_Equals function ensures that the interiors intersect and that no interior or boundary of either geometry intersects the exterior of the other Table 7 3 The DE 9IM pattern matrix for the ST_Equals function b Interior Boundary Exterior Interior T a Boundary Exterior F F Related reference The ST_Disjoint function The ST_Disjoint function pattern matrix simply states that neither the interiors no
291. s 7 7 o o J ST_Point ST_Point ST_MultiPoint ST_Point ST_MultiPoint ST_MultiPoint r J gt e e _ e J ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_Point ST_LineString ST_MultiPoint x e _ ee ST_MultiPoint ST_LineString ST_MultiPoint ST_Point ST_Polygon ST_MultiPoint e e gt e NZ NA ST_MultiPoint ST_Polygon ST_MultiPoint ST_LineString ST_LineString ST_MultiLineString Se Sy DI ST_LineString ST_Polygon ST_MultiLineString ST_Polygon ST_Polygon ST_MultiPolygon Figure 7 9 Intersection sets of geometries Related reference The ST_Intersection function on page 8 51 The ST_Difference function The ST_Difference function returns the portion of the primary geometry that is not intersected by the secondary geometry the logical AND NOT of space The ST_Difference function only operates on geometries of like dimension and returns an ST_GeomCollection ST_MultiPoint ST_MultiLineString or ST_MultiPolygon that has the same dimension as the source geometries In the event that the source geometries are equal an empty geometry is returned 7 8 IBM Informix Spatial Data User s Guide e e 9 ST_Point ST_Point Empty ST_Point ST_Point ST_MultiPoint e J ST_Point ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_MultiPoint Empty J e NZ i NA J ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_LineString ST_LineString ST_LineString VAN z CJ
292. s an ST_Point from a point text representation ST_LineFromText The function creates an ST_LineString from a linestring text representation ST_PolyFromText The function creates an ST_Polygon from a polygon text representation ST_MPointFromText The function creates an ST_MultiPoint from a multipoint representation ST_MLineFromText The function creates an ST_MultiLineString from a multilinestring representation ST_MPolyFromText The function creates an ST_MultiPolygon from a multipolygon representation ST_AsText The function converts an existing geometry into a text representation Related reference Appendix C OGC well known text representation of geometry on page C 1 Well known binary representation You can generate a geometry from the OGC well known binary WKB representation The WKB representation is a contiguous stream of bytes It permits geometry to be exchanged between a client application and an SQL database in binary form Copyright IBM Corp 2001 2010 3 1 ST_GeomFromWKB The function creates an ST_Geometry from a WKB representation of any geometry type ST_PointFromWKB The function creates an ST_Point from a point WKB representation ST_LineFromWKB The function creates an ST_LineString from a linestring WKB representation ST_PolyFromWKB The function creates an ST_Polygon from a polygon WKB representation ST_MPointFromWKB The function creates an ST_MultiPoint fr
293. s in an ST_LineString ST_MultiLineString ST_Polygon or ST_MultiPolygon while preserving the general character of the geometric shape This function uses the Douglas Peucker line simplification algorithm The vertex sequence of the input geometry is recursively subdivided until a run of vertices can be replaced by a straight line segment with no vertex in that run deviating from the straight line by more than the threshold Z values if present are not considered when simplifying a set of vertices IBM Informix Spatial Data User s Guide Syntax SE_Generalize gl ST_Geometry threshold float Return type ST_Geometry unless the input geometry is an ST_Point ST_MultiPoint or an empty geometry of any subtype in which case this function returns NULL Example CREATE TABLE jagged_lines line ST _LineString INSERT INTO jagged_lines VALUES Q linestring 10 10 20 20 20 18 30 30 30 28 40 40 Small threshold no vertices removed SELECT SE _Generalize line 0 5 FROM jagged_lines expression LINESTRING 10 10 20 20 20 18 30 30 30 28 40 40 Larger threshold some vertices removed SELECT SE_Generalize line 2 FROM jagged_lines expression LINESTRING 10 10 40 40 Related reference The SE_Generalize function on page 7 15 The ST_GeometryN function The ST_GeometryN function takes a takes an ST_GeomCollection ST_MultiPoint ST_MultiLineString or ST_MultiPolygon and an INTEGER ind
294. s used to encode the returned geometry Specify 2 for GML2 and 3 for GML3 The default is 2 Return type ST_Geometry Chapter 8 Spatial functions 8 11 Example The first example returns a geometry from the mypoints table as a GML2 representation The second example returns the geometry as a GML3 representation SELECT id ST_ASGML pt 2 FROM mypoints WHERE id 1 id 1 lt gm1 Point gt lt gml coord gt lt gml X gt 95 7 lt gml X gt lt gm1 Y gt 38 1 lt gml Y gt lt gml coord gt lt gml Point gt SELECT id ST_ASGML pt 3 AS gml_v32arg ST_AsGML pt AS gml_v3larg FROM mypoints WHERE id 1 id 1 gml_v32arg lt gml Point gt lt gml pos gt 95 7 38 1 lt gml pos gt lt gml Point gt gml_v3larg lt gml Point gt lt gml pos gt 95 7 38 1 lt gml pos gt lt gml Point gt The INFORMIXDIR extend spatial version examples gm directory contains more information about how to use an XML parser to validate the results of this function The SE_AsKML function 8 12 The SE_AsKMLJ function returns the Keyhole Markup Language KML representation of an ST_Geometry spatial type Typically you use the SE_AsKML function to retrieve the KML representation of a spatial primitive from the server and send it to a client as in SELECT SE_ASKML geomcol FROM mytable The return type of the SE_AsKMLJ function is defined as LVARCHAR You can write user defined routines UDRs in C or SPL to extend the functionality of the
295. sbspace for the SE_MetadataTable table and then running the SE_MetadataInit function For example the following statements put the metadata table in an sbspace named mysbspace ALTER TABLE SE MetadataTable PUT smd IN mysbspace EXECUTE FUNCTION SE_MetadatalInit When the UPDATE STATISTICS MEDIUM or HIGH statements are run on spatial tables the database server stores the statistics in the sbspace specified by the SYSSBSPACENAME configuration parameter in the onconfig file IBM Informix Spatial Data User s Guide Related reference Creating an Sbspace with the Df option Administrator s Reference SBSPACENAME Configuration Parameter Administrator s Reference The spatial_references table The spatial_references table stores data about each map projection that you use to store the spherical geometry of the Earth For example your data may use the Mercator projection The spatial_references table holds information to translate the spatial data into a flat X Y coordinate system You must set up appropriate entries for your spatial data in the spatial_references table The mapping between spheroidal and flat data is called a spatial reference system The spatial reference ID SRID is the unique key for the record in the spatial_references table describing a particular spatial reference system All spatial reference systems that you use in your database must have a record in the spatial_references table All geometries in
296. ser s Guide Table B 5 Horizontal datums continued Factory ID Description OGC well known text string 6133 Estonia 1992 DATUM D_Estonia_1992 SPHEROID GRS_1980 6378137 298 257222101 6602 Dominica 1945 DATUM D_Dominica_1945 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6603 Grenada 1953 DATUM D_Grenada_1953 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6609 NAD_1927 CGQ77 DATUM D_NAD_1927_CGQ77 SPHEROID Clarke_1866 6378206 4 294 9786982 6608 NAD 1927 1976 DATUM D_NAD_1927_Definition_1976 SPHEROID Clarke_1866 6378206 4 294 9786982 6134 PDO Survey Datum DATUM D_PDO_1993 SPHEROID Clarke_1880_RGS 6378249 145 293 465 1993 6605 St Kitts 1955 DATUM D_St_Kitts_1955 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6606 St Lucia 1955 DATUM D_St_Lucia_1955 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6607 St Vincent 1945 DATUM D_St_Vincent_1945 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6140 NAD 1983 Canadian DATUM D_North_American_1983_CSRS98 SPHEROID GRS_1980 Spatial Reference 6378137 298 257222101 System 6141 Israel DATUM D_Israel SPHEROID GRS_1980 6378137 298 257222101 6142 Locodjo 1965 DATUM D_Locodjo_1965 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6143 Abidjan 1987 DATUM D_Abidjan_1987 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6144 Kalianpur 1937 DATUM D_Kalianpur_1937 SPHEROID
297. specify the geometry superclass directly it will be referred to as the ST_Geometry superclass or the ST_Geometry data type Tip You can define a column as type ST_Geometry but ST_Geometry values cannot be inserted into it since they cannot be instantiated However any of the ST_Geometry subclass data type values can be inserted into this column The rest of this section describes the properties of the spatial data types Each subclass data type inherits the properties of the ST_Geometry superclass and adds properties of its own Functions that operate on the ST_Geometry data type also operate on any of the subclass data types However functions that are defined at the subclass level only operate on that data type and its subclasses data types Interior boundary and exterior All geometries occupy a position in space defined by their interior boundary and exterior Exterior All space not occupied by the geometry Boundary Serves as the interface between its interior and exterior Interior The space occupied by the geometry The subclass inherits the interior and exterior properties from ST_Geometry the boundary property differs for each data type The ST_Boundary function takes an ST_Geometry type and returns an ST_Geometry that represents the source ST_Geometry boundary Simple or nonsimple Some subclasses of ST_Geometry ST_LineStrings ST_MultiPoints and ST_MultiLineStrings are either simple or nonsimple They a
298. ssary to show it to describe the concept being discussed For detailed directions on using SQL statements for a particular application development tool or SQL API see the documentation for your product Additional documentation Documentation about this release of IBM Informix products is available in various formats All of the product documentation including release notes machine notes and documentation notes is available from the information center on the web at http publib boulder ibm com infocenter idshelp v117 index jsp Alternatively you can access or install the product documentation from the Quick Start CD that is shipped with the product Compliance with industry standards IBM Informix products are compliant with various standards IBM Informix SQL based products are fully compliant with SQL 92 Entry Level published as ANSI X3 135 1992 which is identical to ISO 9075 1992 In addition many features of IBM Informix database servers comply with the SQL 92 Intermediate and Full Level and X Open SQL Common Applications Environment CAE standards The IBM Informix Geodetic DataBlade Module supports a subset of the data types from the Spatial Data Transfer Standard SDTS Federal Information Processing Standard 173 as referenced by the document Content Standard for Geospatial Metadata Federal Geographic Data Committee June 8 1994 FGDC Metadata Standard IBM Informix Dynamic Server IDS Enterprise E
299. system Typically this error occurs when the buffer function generates a geometry with coordinates that are beyond the source geometry s coordinate system which the new geometry inherits You may need to adjust the false origin and system units for your data Please refer to the description of the ST_Transform function in Chapter 8 Spatial functions on page 8 1 for additional information USE20 Invalid parameter in function FUNCTION Explanation One of the parameters passed to the function is invalid User response Review the syntax of the function listed in Chapter 8 Spatial functions on page 8 1 Correct the invalid parameter and resubmit the function USE21 Geometry integrity error in function FUNCTION Explanation An inconsistency has been detected in a geometry s internal data structure User response If this error continues to occur contact IBM Informix Technical Support for assistance USE22 Too many points in feature Explanation Returned if the buffer function creates a feature that exceeds the maximum number of points specified as a parameter to the function User response Increase the size of the maximum number of points parameter and resubmit the function USE23 Spatial reference conflict SRID1 vs SRID2 Explanation The geometries passed to the function did not share the same spatial reference system User response Convert one of the geometries
300. t closed The second row returns 1 because the multilinestring stored in the mln1 column is closed A multilinestring is closed if all of its linestring elements are closed SELECT ST_IsClosed min1 Is_it_closed FROM closed_mlinestring is_it_closed f t The ST_IsEmpty function The ST_IsEmpty function returns t TRUE if the geometry is empty otherwise returns f FALSE See a description of properties of geometries in Properties of spatial data types fon page 2 1 Syntax ST_IsEmpty g1 ST Geometry Return type BOOLEAN Chapter 8 Spatial functions 8 55 Example The CREATE TABLE statement below creates the empty_test table with geotype which stores the data type of the subclasses that are stored in the g1 ST_Geometry column CREATE TABLE empty_test geotype varchar 20 gl ST_Geometry The following INSERT statements insert two records each for the geometry subclasses point linestring and polygon one record is empty and one is not INSERT INTO empty_test VALUES Point ST PointFromText point 10 02 20 01 1000 Me INSERT INTO empty_test VALUES Point ST PointFromText point empty 1000 INSERT INTO empty_test VALUES Linestring ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO empty_test VALUES Linestring ST_LineFromText linestring empty 1000 J INSERT INTO empty_test VALUES Polygon ST_PolyFromText polygon
301. t studying shoreline birds needs to determine the shoreline for the lakes within a particular area The lakes are stored as ST_MultiPolygon type in the waterbodies table created with the following CREATE TABLE statement CREATE TABLE WATERBODIES wbid integer waterbody ST MultiPolygon In the following SELECT statement the ST_Perimeter function returns the perimeter surrounding each body of water while the SUM operator aggregates the perimeters to return their total SELECT SUM ST_Perimeter waterbody FROM waterbodies The SE_PerpendicularPoint function 8 86 The SE_PerpendicularPoint function finds the perpendicular projection of a point on to the nearest segment of a linestring or multilinestring If two or more such perpendicular projected points are equidistant from the input point they are all returned If no perpendicular point can be constructed an empty point is returned If the input linestring has Z values or measures the Z value or measure of the perpendicular point are computed by linear interpolation between the adjacent vertices Syntax SE_PerpendicularPoint ST_LineString ST Point SE_PerpendicularPoint ST MultiLineString ST Point IBM Informix Spatial Data User s Guide Return type ST_MultiPoint Example CREATE TABLE linestring_test line ST_LineString Create a U shaped linestring INSERT INTO linestring_test VALUES ST_LineFromText linestring z 0 10 1 0 0 3 10 0 5 10 10 7 0
302. t the lot_id and lot data dynamically Create the SQL insert statement to populate the lots table The question marks are parameter markers that indicate the column values that will be inserted at run time sprintf sql_stmt INSERT INTO lots lot_id lot VALUES ST GeomFromWKB d srid Prepare the SQL statement for execution rc SQLPrepare hstmt unsigned char sql_stmt SQL_NTS Bind the lot_id to the first parameter pcbvaluel 0 rc SQLBindParameter hstmt 1 SQL_PARAM_INPUT SQL _C_SLONG SQL_INTEGER 0 0 amp lot_id 0 amp pcbvaluel Bind the lot geometry to the second parameter pcbvalue2 lot_wkb_len rc SQLBindParameter hstmt 2 SQL_PARAM_INPUT SQL_C BINARY SQL_INFX_UDT_LVARCHAR lot_wkb_len 0 lot_wkb_buf lot_wkb_len amp pcbvalue2 Execute the insert statement rc SQLExecute hstmt The SE_InRowSize function 8 48 The SE_InRowSize function returns the size of the in row portion of a geometry Geometries which are less than 930 bytes are stored entirely in row that is the entire value is stored in a table s dbspace The SE_InRowSize function returns the size of the in row portion of a geometry Geometries which are less than 930 bytes are stored entirely in row that is the entire value is stored in a table s dbspace You can use this function to obtain an estimate of the amount of disk space consumed by one or more geomet
303. t_Conformal_Conic 43021 Polyconic PROJECTION Polyconic 43022 Quartic Authalic PROJECTION Quartic_Authalic 43023 Loximuthal PROJECTION Loximuthal 43024 Bonne PROJECTION Bonne 43025 Hotine 2 Pt Natural Origin PROJECTION Hotine_Oblique_Mercator_Two_ Point_Natural_Origin 43026 Stereographic PROJECTION Stereographic 43027 Equidistant Conic PROJECTION Equidistant_Conic 43028 Cassini PROJECTION Cassini 43029 Van der Grinten I PROJECTION Van_der_Grinten_I 43030 Robinson PROJECTION Robinson 43031 Two Point Equidistant PROJECTION Two_Point_Equidistant 43032 Azimuthal Equidistant PROJECTION Azimuthal_Equidistant 43033 Lambert Azimuthal Equal Area PROJECTION Lambert_Azimuthal_Equal_Area 43034 Cylindrical Equal Area PROJECTION Cylindrical_Equal_Area 43035 Hotine 2 Point Center PROJECTION Hotine_Oblique_Mercator_Two_ Point_Center 43036 Hotine Azimuth Natural Origin PROJECTION Hotine_Oblique_Mercator_Azimuth _Natural_Origin 43037 Hotine Azimuth Center PROJECTION Hotine_Oblique_Mercator_Azimuth _Center 43038 Double Stereographic PROJECTION Double_Stereographic 43039 Krovak Oblique Lambert PROJECTION Krovak 43040 New Zealand Map Grid PROJECTION New_Zealand_Map_Grid 43041 Orthographic PROJECTION Orthographic 43042 Winkel Tripel PROJECTION Winkel_Tripel 43043 Aitoff PROJECTION Aitoff 43044 Hammer Aitoff PROJECTION Hammer_Aitoff 43045 Flat Polar Quartic PROJECTION
304. te order Byte 0 Shape Type 3 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumParts NumParts Integer 1 Little endian E 2 IBM Informix Spatial Data User s Guide Position Field Value Type Number Byte order Byte 40 NumPoints NumPoints Integer 1 Little endian Byte 44 Parts Parts Integer Num Parts Little endian Byte X Points Points Point NumPoints Little endian Tip X 44 4 NumParts Polygon A polygon consists of one or more rings A ring is a connected sequence of four or more points that form a closed non self intersecting loop A polygon may contain multiple outer rings The order of vertices or orientation for a ring indicates which side of the ring is the interior of the polygon The neighborhood to the right of an observer walking along the ring in vertex order is the neighborhood inside the polygon Vertices of rings defining holes in polygons are in a counterclockwise direction Vertices for a single ringed polygon are therefore always in clockwise order The rings of a polygon are referred to as its parts Because this specification does not forbid consecutive points with identical coordinates shapefile readers must handle such cases On the other hand the degenerate zero length or zero area parts that might result are not allowed The following fields are for a polygon Box The bounding box for the polygon stored in the order Xmin Ymin Xmax Ymax NumParts The number of rings in
305. test VALUES LineString ST_LineFromText linestring m 10 02 20 01 1 23 10 32 23 98 4 56 11 92 25 64 7 89 1000 J INSERT INTO coorddim_test VALUES Polygon ST_PolyFromText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 INSERT INTO coorddim_test VALUES Polygon ST_PolyFromText polygon zm 10 02 20 01 9 87 1 23 11 92 35 64 7 65 2 34 25 02 34 15 6 54 3 45 19 15 33 94 5 43 4 56 10 02 20 01 9 87 1 23 1000 J The SELECT statement lists the subclass name stored in the geotype column with the dimension of that geometry SELECT geotype ST_CoordDim g1 coord_dimension FROM coorddim_test geotype coord_dimension Point Point LineString LineString Polygon Polygon PM WM WP 6 row s retrieved The SE_CreateSRID function 8 24 The SE_CreateSRID function is a utility function that given the X and Y extents of a spatial data set computes the false origin and system units and creates a new entry in the spatial_references table Appropriate offsets and scale factors for typical Z values and M values are also provided The spatial_references table holds data about spatial reference systems A spatial reference system is a description of a coordinate system for a set of geometric objects it gives meaning to the X and Y values that are stored in the database You need to specify an SRID of a spatial reference system when you load spatial data into a databas
306. text string 6009 Clarke 1866 DATUM D_Clarke_1866_Michigan SPHEROID Clarke_1866_Michigan Michigan 6378450 047 294 978684677 6034 Clarke 1880 DATUM D_Clarke_1880 SPHEROID Clarke_1880 6378249 138 293 466307656 6013 Clarke 1880 Arc DATUM D_Clarke_1880_Arc SPHEROID Clarke_1880_Arc 6378249 145 293 466307656 6010 Clarke 1880 DATUM D_Clarke_1880_Benoit SPHEROID Clarke_1880_Benoit Benoit 6378300 79 293 466234571 6011 Clarke 1880 IGN _DATUM D_Clarke_1880_IGN SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6012 Clarke 1880 RGS DATUM D_Clarke_1880_RGS SPHEROID Clarke_1880_RGS 6378249 145 293 465 6014 Clarke 1880 SGA DATUM D_Clarke_1880_SGA SPHEROID Clarke_1880_SGA 6378249 2 293 46598 6042 Everest 1830 DATUM D_Everest_1830 SPHEROID Everest_1830 6377299 36 300 8017 6015 Everest DATUM D_Everest_Adj_1937 SPHEROID Everest_Adjustment_1937 adjustment 1937 6377276 345 300 8017 6044 Everest definition DATUM D_Everest_Def_1962 SPHEROID Everest_Definition_1962 1962 6377301 243 300 8017255 6016 Everest definition DATUM D_Everest_Def_1967 SPHEROID Everest_Definition_1967 1967 6377298 556 300 8017 6045 Everest definition DATUM D_Everest_Def_1975 SPHEROID Everest_Definition_1975 1975 6377299 151 300 8017255 6018 Everest modified DATUM D_Everest_Modified SPHEROID Everest_1830_Modified 6377304 063 300 8017 6031 GEM gravity DATUM D_GEM_10C SPHEROID GEM_10C 6378137
307. the accuracy of performance compatibility or any other claims related to non IBM products Questions on the capabilities of non IBM products should be addressed to the suppliers of those products All statements regarding IBM s future direction or intent are subject to change or withdrawal without notice and represent goals and objectives only All IBM prices shown are IBM s suggested retail prices are current and are subject to change without notice Dealer prices may vary This information is for planning purposes only The information herein is subject to change before the products described become available This information contains examples of data and reports used in daily business operations To illustrate them as completely as possible the examples include the names of individuals companies brands and products All of these names are fictitious and any similarity to the names and addresses used by an actual business enterprise is entirely coincidental COPYRIGHT LICENSE This information contains sample application programs in source language which illustrate programming techniques on various operating platforms You may copy IBM Informix Spatial Data User s Guide modify and distribute these sample programs in any form without payment to IBM for the purposes of developing using marketing or distributing application programs conforming to the application programming interface for the operating platform for which the s
308. the polygon NumPoints The total number of points for all rings Parts An array of length NumParts Stores for each ring the index of its first point in the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each ring in the polygon are stored end to end The points for ring 2 follow the points for ring 1 and so on The parts array holds the array index of the starting point for each ring There is no delimiter in the points array between rings The following are important notes about polygon shapes e The rings are closed the first and last vertex of a ring must be the same e The order of rings in the points array is not significant e Polygons stored in a shapefile must be clean e A clean polygon is one that has no self intersections This means that a segment belonging to one ring may not intersect a segment belonging to another ring The rings of a polygon can touch each other at vertices but not along segments Colinear segments are considered intersecting e A clean polygon is one that has the inside of the polygon on the correct side of the line that defines it The neighborhood to the right of an observer walking Appendix E ESRI shape representation E 3 along the ring in vertex order is the inside of the polygon Vertices for a single ringed polygon are therefore always in clockwise order Rings defining holes in these polygons have a counterclockwise o
309. tion eliminates the need for a temporary dbspace but your spatial data must be presorted in the table This means that it must be inserted into the table in sorted order or sorted by means of a clustered B tree index after it is loaded You should also note that the bottom up build option only makes sense if you load all of your spatial data into a table before you create an R tree index There is no performance advantage to either build option if you create an index on an empty table and then insert data Depending on certain characteristics of your spatial data an index built from the top down may be more effective than one built from the bottom up Properties that can adversely affect a bottom up built index include many objects that overlap Chapter 4 R tree indexes 4 3 each other or many objects that are very close together such that the sort key produced by the SE_SpatialKey function is the same value for a large number of objects Related reference The SE_SpatialKey function on page 8 99 Functional R tree indexes Under certain conditions you can create a functional R tree index using one of the several spatial data type functions A functional index is built using the value returned by a function rather than the value of a column in a table For example you can create an R tree index on the centroids of the objects in a table rather than on the objects themselves CREATE TABLE poly_tab poly_col ST Geometr
310. tion parameters Map projections Appendix C OGC well known text representation of geometry Well known text representation in a C program ee he ee Oe oN OG Well known text representation in an SQL editor Modified well known text representation Appendix D OGC well known binary representation of geometry Numeric type definitions ood mo Be hy Rosy Ao a om a XDR big endian encoding of numeric types NDR little endian encoding of numeric types Conversion between the NDR and XDR representations of WKB geometry Description of WKBGeometry byte streams i ee a GS Assertions for well known binary representation for geometry Appendix E ESRI Saps ARETA Shape type values Shape types in XY space Point 3 4 MultiPoint PolyLine Polygon Measured shape types in XY space PointM MultiPointM PolyLineM PolygonM Shape types in XYZ space F PointZ MultiPointZ PolyLineZ PolygonZ Measured shape types in XYZ space PointZM a h MultiPointZM PolyLineZM PolygonZM Appendix F Values for the geometry_type column 8 114 8 114 8 115 8 115 A 1 A 2 A 6 B 1 B 1 B 3 B 4 B 5 B 6 B 8 B 16 B 16 B 17 D 1 E 1 E 2 E 2 z B33 E 4 H 5 lt E5 lt H 5 E 6 E 7 E 7 E8 EY E 10 Contents E 10 E 10 E 11 E 12 F 1 vii Appendix G Error messages sosoo ee ee ee ee ee Ge
311. tion takes an ST_Geometry and returns its dimension as an integer Z coordinates Some geometries have an associated altitude or depth Each of the points that form the geometry of a feature can include an optional Z coordinate that represents an altitude or depth normal to the earth s surface The SE_Is3D predicate function takes an ST_Geometry and returns t TRUE if the function has Z coordinates and f FALSE otherwise Measures Measures are values assigned to each coordinate The value represents anything that can be stored as a double precision number The SE_IsMeasured function takes an ST_Geometry and returns t TRUE if it contains measures and f FALSE otherwise Spatial reference system The spatial reference system identifies the coordinate transformation matrix for each geometry All spatial reference systems known to the database are stored in the spatial_references table The ST_SRID function takes an ST_Geometry and returns its spatial reference identifier as an integer Related concepts The spatial_references table on page 1 5 ST_Point data type 2 4 The ST_Point data type is a zero dimensional geometry that occupies a single location in coordinate space ST_Point is used to define features such as oil wells landmarks and elevations Properties An ST_Point has a single X Y coordinate value is always simple and has a NULL boundary An ST_Point may include a Z coordinate and an
312. tipoint st_multilinestring e st_multipolygon Example The geometrytype_test table contains the g1 ST_Geometry column CREATE TABLE geometrytype_test gl ST Geometry The following INSERT statements insert each geometry subclass into the g1 column INSERT INTO geometrytype_test VALUES ST_GeomFromText point 10 02 20 01 1000 INSERT INTO geometryType_test VALUES ST_GeomFromText linestring 10 01 20 01 10 01 30 01 10 01 40 01 1000 J INSERT INTO geometrytype_test VALUES ST_GeomFromText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 J INSERT INTO geometrytype_test VALUES ST_GeomFromText multipoint 10 02 20 01 10 32 23 98 11 92 25 64 1000 INSERT INTO geometrytype_test VALUES ST_GeomFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 J INSERT INTO geometrytype_test VALUES ST_GeomFromText multipolygon 10 02 20 01 11 92 35 64 25 02 IBM Informix Spatial Data User s Guide 34 15 19 15 33 94 10 02 20 01 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 90 51 71 21 73 1000 s The following query lists the geometry type of each subclass stored in the g1 geometry column SELECT ST_GeometryType g1 Geometry type FROM geometrytype_ test geometry_type st_point geometry_type st_linestring geometry_type st_polygon geometry_type st_multipoint geometry_type st_multilinestring geometry_typ
313. to bottom into the string T F FFF b Interior Boundary Exterior Interior T a Boundary i Exterior F F j Next the table relate_test is created with the following CREATE TABLE statement CREATE TABLE relate_test g1 ST_Geometry g2 ST_Geometry g3 ST_Geometry The following INSERT statements insert a sample subclass into the relate_test table INSERT INTO relate_test VALUES ST_PointFromText point 10 02 20 01 1000 ST_PointFromText point 10 02 20 01 1000 ST_PointFromText point 30 01 20 01 1000 The following SELECT statement and the corresponding result set lists the subclass name stored in the geotype column with the dimension of that geotype SELECT ST Relate gl g2 T F FFF equals ST_Relate gl g3 T F FFF not_equals FROM relate_test equals not_equals t f The SE_Release function The SE_Release function returns a text string containing the installed version and release date of the IBM Informix spatial extension Syntax SE_Release Return type A text string containing the installed version and release date The SE_ShapeToSQL function 8 98 The SE_ShapeToSQL function constructs an ST_Geometry given its ESRI shape representation The SRID of the St_Geometry is 0 Syntax SE_ShapeToSQL ShapeGeometry lvarchar IBM Informix Spatial Data User s Guide Return type ST_Geometry Example The following C code fragment contains ODBC fu
314. to end The points for ring 2 follow the points for ring 1 and so on The parts array holds the array index of the starting point for each ring There is no delimiter in the points array between rings Z Range The minimum and maximum Z values for the PolygonZ stored in the order Zmin Zmax Appendix E ESRI shape representation E 9 Z Array An array of length NumPoints The Z values for each ring in the PolygonZ are stored end to end The Z values for ring 2 follow the Z values for ring 1 and so on The parts array holds the array index of the starting Z value for each ring There is no delimiter in the Z value array between rings The following are important notes about PolygonZ shapes e The rings are closed the first and last vertex of a ring must be the same e The order of rings in the points array is not significant The following table shows PolygonZ byte stream contents Position Byte 0 Byte 4 Byte 36 Byte 40 Byte 44 Byte X Byte Y Byte Y 8 Byte Y 16 Field Shape Type Box NumParts NumPoints Parts Points Zmin Zmax Z Array Value 19 Box NumParts NumPoints Parts Points Zmin Zmax Z Array Type Integer Double Integer Integer Integer Point Double Double Double Number 1 4 1 1 NumParts NumPoints 1 1 NumPoints Byte order Little endian Little endian Little endian Little endian Little endian Little endian Little endian Little endian Little endian
315. total city lot area not covered by buildings In fact the engineer wants the sum of the lot area after the building area has been removed CREATE TABLE buildingfootprints building_id integer lot_id integer footprint ST_MultiPolygon CREATE TABLE lots lot_id integer lot ST_MultiPolygon The city engineer equijoins the buildingfootprints and lots table on the lot_id column and takes the sum of the area of the difference of the lots less the building footprints SELECT SUM ST_Area ST_Difference lot footprint ST_MultiPolygon FROM buildingfootprints bf lots WHERE bf lot_id lots lot_id IBM Informix Spatial Data User s Guide Related reference The ST_Difference function on page 7 8 The ST_Dimension function The ST_Dimension function returns the dimension of a geometry object A geometry can have one of three dimensions 0 The geometry has neither length nor area 1 The geometry has length 2 The geometry has area Syntax ST_Dimension gl ST_Geometry Return type INTEGER Example The dimension_test table is created with the columns geotype and g1 The geotype column stores the name of the subclass stored in the g1 ST_Geometry column CREATE TABLE dimension test geotype varchar 20 gl ST_Geometry The following INSERT statements insert a sample subclass into the dimension_test table INSERT INTO dimension_test VALUES Point ST_PointFromText point 10 02 20 01 1000
316. tralian Geodetic DATUM D_Australian_1984 SPHEROID Australian 6378160 298 25 Datum 1984 6204 Ain el Abd 1970 DATUM D_Ain_el_Abd_1970 SPHEROID International_1924 6378388 297 6289 Amersfoort DATUM D_Amersfoort SPHEROID Bessel_1841 6377397 155 299 1528128 6208 Aratu DATUM D_Aratu SPHEROID International_1924 6378388 297 6209 Arc 1950 DATUM D_Arc_1950 SPHEROID Clarke_1880_Arc 6378249 145 293 466307656 6210 Arc 1960 DATUM D_Arc_1960 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6901 Ancienne DATUM D_ATF SPHEROID Plessis_1817 6376523 308 64 Triangulation Francaise 6122 Average Terrestrial DATUM D_ATS_1977 SPHEROID ATS_1977 6378135 298 257 System 1977 6212 Barbados 1938 DATUM D_Barbados_1938 SPHEROID Clarke_1880_RGS 6378249 145 293 465 6211 Batavia DATUM D_Batavia SPHEROID Bessel_1841 6377397 155 299 1528128 6213 Beduaram DATUM D_Beduaram SPHEROID Clarke_1880_IGN 6378249 2 293 46602 6214 Beijing 1954 DATUM D_Beijing_1954 SPHEROID Krasovsky_1940 6378245 298 3 B 8 IBM Informix Spatial Data User s Guide Table B 5 Horizontal datums continued Factory ID Description OGC well known text string 6215 Reseau National DATUM D_Belge_1950 SPHEROID International_1924 6378388 297 Belge 1950 6313 Reseau National DATUM D_Belge_1972 SPHEROID International_1924 6378388 297 Belge 1972 6216 Bermuda 1
317. transmitted between the client and server They should not be used as C language data structures See the following figure for an example of such a byte stream Basic Type definitions byte 1 byte uint32 32 bit unsigned integer 4 bytes double double precision number 8 bytes Building Blocks Point LinearRing Point double x double y double z double m E LinearRing uint32 numPoints Point points numPoints enum wkbGeometryType wkbPoint 1 wkbLineString 2 wkbPolygon 35 wkbMul tiPoint 4 wkbMul tiLineString 5 wkbMultiPolygon 6 wkbGeometryCol lection 7 wkbPointZ 1001 wkbLineStringZ 1002 wkbPolygonZ 1003 wkbMultiPointZ 1004 wkbMul tiLineStringZ 1005 wkbMul1tiPolygonZ 1006 wkbGeometryCol lectionZ 1007 wkbPointM 2001 wkbLineStringM 2002 wkbPolygonM 2003 wkbMul ti PointM 2004 wkbMul tiLineStringM 2005 wkbMultiPolygonM 2006 wkbGeometryCol lectionM 2007 wkbPointZM 3001 wkbLineStringZM 3002 wkbPolygonZM 3003 wkbMul tiPointZM 3004 wkbMultiLineStringZM 3005 wkbMultiPolygonZM 3006 wkbGeometryCollectionZM 3007 E enum wkbByteOrder wkbXDR 0 Big Endian wkbNDR 1 Little Endian E IBM Informix Spatial Data User s Guide WKBPoint byte byteOrder uint32 wkbType 1 Point point WKBLineString byte byteOrder uint32 wkbType 2 uint32 numPoints Point points numPoints
318. tries stored using this version of the DataBlade module Similarly this version of the Spatial DataBlade may not be able to interpret geometries stored using a future version If an upgrade mechanism is provided with a new version of this DataBlade module use it on your data as described in the release notes If an upgrade mechanism is not provided you must unload your USE23 USE33 data with the old DataBlade module version and reload it with the new version USE28 Invalid text in FUNCTION Explanation The text string entered with the well known text representation function is invalid User response Correct the string and resubmit the function Refer to Appendix C OGC well known text representation of geometry on page C 1 for a valid text string description USE29 Unexpected system error in FUNCTION Explanation An internal error occurred while creating a geometry The system was not able to determine why this error occurred User response Contact IBM Informix Technical Support for assistance Please include this error number and any other related error messages and information from the INFORMIXDIR on1ine log file If you are using the Spatial DataBlade module in conjunction with ArcSDE from ESRI please also include any related information from the SDEHOME etc sde errlog file USE30 Overlapping polygon rings in FUNCTION Explanation The internal rings of a polygon m
319. tring zm empty Empty linestring with Z coordinates and measures ST_LineString linestring 10 05 10 28 20 95 20 89 Linestring ST_LineString linestring z 10 05 10 28 3 09 20 95 31 98 4 72 Linestring with Z coordinates 21 98 29 80 3 51 ST_LineString linestring m 10 05 10 28 5 84 20 95 31 98 9 01 Linestring with measures 21 98 29 80 12 84 ST_LineString linestring zm 10 05 10 28 3 09 5 84 20 95 31 98 4 72 Linestring with Z coordinates and 9 01 21 98 29 80 3 51 12 84 measures ST_Polygon polygon empty Empty polygon ST_Polygon polygon z empty Empty polygon with Z coordinates ST_Polygon polygon m empty Empty polygon with measures ST_Polygon polygon zm empty Empty polygon with Z coordinates and measures ST_Polygon polygon 10 10 10 20 20 20 20 15 10 10 Polygon ST_Polygon polygon z 10 10 3 10 20 3 20 20 3 2015 4 10 10 Polygon with Z coordinates 3 ST_Polygon polygon m 10 10 8 10 20 9 20 20 9 20 15 9 10 Polygon with measures 10 8 ST_Polygon polygon zm 10 10 3 8 10 20 3 9 20 20 3 9 2015 Polygon with Z coordinates and 49 10 1038 measures ST_MultiPoint multipoint empty Empty multipoint ST_MultiPoint multipoint z empty Empty multipoint with Z coordinates ST_MultiPoint multipoint m empty Empty multipoint with measures ST_MultiPoint multipoint zm empty Empty multipoint with Z coordinates and measures ST_MultiPoint multipoint 10 10
320. ts MultiLineStrings and MultiPolygons are difficult to estimate The numbers shown in the table are based on the types of data sets that these data types are most often applied to broadcast patterns for MultiPoints stream networks for MultiLineStrings and island topology for MultiPolygons Data type Average points per feature Point 1 LineString urban 5 LineString rural 50 Polygon urban 7 Copyright IBM Corp 2001 2010 6 1 Data type Average points per feature Polygon rural 150 MultiPoint 50 MultiLineString 250 MultiPolygon 1000 The coordinate factor is based on the dimensions of the coordinates stored by the spatial column Select the coordinate factor from the table below Coordinate type Coordinate factor XY 4 8 XYZ 7 2 XY and measures 7 2 XYZ and measures 9 6 If your layer includes annotation set the annotation size to 300 bytes this is the average space required to store most annotation This includes the space required to store text placement geometry lead line geometry and various attributes describing the annotation s size and font Estimate the size of non spatial columns You can estimate the row size of fixed sized columns by querying the systables system catalog table You must estimate the average size of variable length columns To determine the size of the remaining columns of a spatial table create the table without the spatial column
321. ts and lot lines Related reference The ST_Contains function on page 7 6 The ST_Contains function on page 7 21 The ST_ConvexHull function 8 22 The ST_ConvexHull function returns the convex hull of a geometry object Syntax ST_ConvexHull g1 ST_ Geometry Return type ST_Geometry Example The example creates the convexhull_test table that has two columns geotype and g1 The geotype column is of VARCHAR 20 type and holds the name of the geometry subclass that is stored in g1 an ST_Geometry column CREATE TABLE convexhull_test geotype varchar 20 gl ST_Geometry The following INSERT statements insert several geometry subclasses into the convexhull_test table INSERT INTO convexhull_test VALUES Point ST_PointFromText point 10 02 20 01 1000 INSERT INTO convexhull_test VALUES Linestring ST_LineFromText linestring 10 02 20 01 10 32 23 98 11 92 25 64 1000 IBM Informix Spatial Data User s Guide INSERT INTO convexhull_test VALUES Polygon ST_PolyFromText polygon 10 02 20 01 11 92 35 64 25 02 34 15 19 15 33 94 10 02 20 01 1000 s INSERT INTO convexhul _test VALUES MultiPoint ST_MPointFromText multipoint 10 02 20 01 10 32 23 98 11 92 25 64 1000 s INSERT INTO convexhul _test VALUES MultiLineString ST_MLineFromText multilinestring 10 02 20 01 10 32 23 98 11 92 25 64 9 55 23 75 15 36 30 11 1000 INSERT INTO convexhull
322. u must be using IBM Informix Version 9 3 or later Required You must create an R tree index on the geometry column on which you want to perform nearest neighbor queries Syntax SE_Nearest gl ST_Geometry g2 ST_Geometry SE_NearestBbox gl ST Geometry g2 ST Geometry Return type BOOLEAN Example The cities table contains the names and locations of world cities CREATE TABLE cities name varchar 255 locn ST_Point Populate this table with data from a DB Access load file cities load this data file is included with the IBM Informix Spatial DataBlade Module as part of this example it contains the names and locations of approximately 300 world cities as the example shows LOAD FROM cities load INSERT INTO cities Create an R tree index on the locn column this is required by the SE_Nearest function CREATE INDEX cities_idx ON cities locn ST Geometry_ops USING RTREE UPDATE STATISTICS FOR TABLE cities locn IBM Informix Spatial Data User s Guide Now search for the five cities nearest London SELECT FIRST 5 name FROM cities WHERE SE_Nearest locn O point 51 name London name Birmingham name Paris name Nantes name Amsterdam Warning Using a fragmented R tree index for nearest neighbor queries raises an error Results will not be returned in nearest distance order because the query is executed on each separate index fragment and results from each fragment are combined in an unspecified order
323. ultiPolygon e e J e ST_MultiPoint ST_LineString ST_MultiPoint ST_Polygon gt S P ST_LineString ST_LineString ST_LineString ST_Polygon Figure 7 6 Crossing geometries Related reference The ST_Crosses function on page 8 26 The ST_Within function The ST_Within function returns t TRUE if the first geometry is completely within the second geometry The boundary and interior of the first geometry are not allowed to intersect the exterior of the second geometry ST_Within tests for the exact opposite result of ST_Contains Chapter 7 Determine spatial relationships and transform geometries 7 5 J ST_Point ST_MultiPoint ST_Point ST_LineString J e ST_MultiPoint ST_MultiPoint ST_MultiPoint ST_LineString e e ST_Point ST_Polygon ST_MultiPoint ST_Polygon ST_LineString ST_LineString ST_LineString ST_Polygon L ST_LineString ST_Polygon Figure 7 7 The ST_Within function Related reference The ST_Within function on page 8 110 The ST_Contains function The ST_Contains function returns t TRUE if the second geometry is completely contained by the first geometry The boundary and interior of the second geometry are not allowed to intersect the exterior of the first geometry ST_Contains returns the opposite result of ST_Within 7 6 IBM Informix Spatial Data User s Guide O O So NS ST_MultiPoint ST_Point ST_MultiPoint ST_MultiPoint ST_LineStr
324. undary of an ST_Polygon and the space enclosed between the rings defines the interior of ST_Polygon The rings of an ST_Polygon can intersect at a tangent point but never cross In addition to the other properties inherited from the superclass ST_Geometry ST_Polygon has area The following figure shows examples of ST_Polygon objects 1 is an ST_Polygon whose boundary is defined by an exterior ring 2 is an ST_Polygon whose boundary is defined by an exterior ring and two interior rings The area inside the interior rings is part of the ST_Polygon s exterior 3 is a legal ST_Polygon because the rings intersect at a single tangent point J 1 2 3 Figure 2 3 Examples of ST_Polygon objects Functions The following functions operate on ST_Polygon IBM Informix Spatial Data User s Guide ST_Area The function returns the polygon s area as a double precision number ST_ExteriorRing The function returns the polygon s exterior ring as an ST_LineString ST_NumInteriorRing The function returns the number of interior rings that the polygon contains ST_InteriorRingN The function takes an ST_Polygon and an index and returns the nth interior ring as an ST_LineString ST_Centroid The function returns an ST_Point that is the center of the ST_Polygon s envelope ST_PointOnSurface The function returns an ST_Point that is guaranteed to be on the surface of the ST_Polygon ST_Perimeter The function returns th
325. ve performance because it eliminates the need to examine objects outside the area of interest Without an R tree index a query would need to evaluate every object to find those that match the query criteria When you create an index you can specify an access method and an operator class if you do not specify an access method the default B tree access method is used The access method organizes the data in a way that speeds up access The operator class is used by the optimizer to determine whether to use an index in a query To create an R tree index you must specify an operator class that supports an R tree index on the data type you want to index The operator class you use for IBM Informix spatial data types is ST_Geometry_Ops The B tree access method creates a one dimensional ordering that speeds access to traditional numeric or character data You can use B tree to index a column of non spatial data or to create a functional index on the results of a spatial function that returns numeric or character data For example you could create a functional B tree index on the results of the ST_NumPoints function because ST_NumPoints returns an integer value Restriction The B tree access method indexes numeric and character data only You cannot use the B tree access method to index spatial data The syntax for creating an index is described in detail in the CREATE INDEX statement in IBM Informix Guide to SQL Syntax For a detailed d
326. verts the point coordinates into an ST_Point geometry before the INSERT statement inserts it into the pt1 column INSERT INTO point_test VALUES ST_Point 10 01 20 03 1000 The ST_PointFromGML function 8 88 The ST_PointFromGML function takes a GML2 or GML3 string representation of an ST_Point and an optional spatial reference ID and returns a point object Syntax ST_PointFromGML gmlstring lvarchar ST_PointFromGML gmlstring lvarchar SRID integer Return type ST_Point Example The point_t table contains the gid INTEGER column which uniquely identifies each row the pdesc column which describes the point and the p1 column which stores the point In this example GML3 is shown CREATE TABLE point_t gid INTEGER pdesc VARCHAR 30 pl ST Point INSERT INTO point_t VALUES l This point is a simple XY point ST_PointFromGML lt gm1 Point srsName DEFAULT srsDimension 2 gt lt gm pos gt 10 02 20 01 lt gml pos gt lt gml Point gt 1000 INSERT INTO point_t VALUES 2 This point is a XYZ point ST_PointFromGML lt gml Point srsName DEFAULT srsDimension 3 gt lt gml pos gt 10 02 20 01 5 lt gml pos gt lt gm1 Point gt 1000 INSERT INTO point_t VALUES 35 This point is a XYM point ST_PointFromGML lt gm l Point srsName DEFAULT srsDimension 3 gt lt gml pos gt 10 02 20 01 7 lt gml pos gt lt gml Point gt 1000 INSERT INTO point_t VALUES 4 This point
327. y CREATE INDEX centroid_idx ON poly_tab ST_Centroid poly_col ST_Geometry_ops USING RTREE You can use the following spatial data type functions in a functional index e ST_Centroid e ST_EndPoint e ST_Envelope e SE_Midpoint e ST_Point e ST_PointN e ST_PointOnSurface e ST_StartPoint Verify that the index is correctly built To verify whether an index was successfully built use the oncheck utility The output from oncheck for a successfully built index starts as shown WARNING index check requires a s lock on tables whose lock level is page Information for Partition num 1049006 Node Level 0 Pagenum 32 Usage 55 7 No of Children 11 right 1 Refer to your IBM Informix Administrator s Guide for information about using the oncheck utility The spatial operator class ST_Geometry_Ops 4 4 An operator class defines operators called strategy functions that can use an index The operator class that the IBM Informix spatial data types require ST_Geometry_Ops Restriction Do not use rtree_ops the default R tree operator class for the secondary access method The strategy functions for the ST_Geometry_Ops operator classes are e ST_Contains ST_Crosses e ST_Equals IBM Informix Spatial Data User s Guide e SE _EnvelopesIntersect e ST_Intersects e SE _Nearest e SE_NearestBbox e ST_Overlaps e ST_Touches e ST_Within How spatial operators use R tree index
328. y Language You use specialized spatial data type functions to compare the values in spatial columns to determine if the values intersect overlap or are related in many different ways These functions can answer questions like Is this school within five miles of a hazardous waste site An application programmer can use an SQL query to join a table storing sensitive sites such as schools playgrounds and hospitals to another table containing the locations of hazardous sites and return a list of sensitive areas at risk For example the following figure shows that a school and hospital lie within the five mile radius of two hazardous site locations and the nursing home lies safely outside both radii Hospital EL ILL ALLL c School Nursing Home Figure 1 1 Determining whether sensitive sites are within dangerous areas You use the ST_Overlaps function to evaluate whether the polygon representing the building footprint of the school overlaps the circular polygon that represents the five mile radius of a hazardous waste site The building footprints of the Copyright IBM Corp 2001 2010 1 1 school hospital and nursing home are stored in the ST_Polygon data type and the location of each hazardous waste site is stored in an ST_Point type Comparison of spatial and geodetic data The IBM Informix spatia
329. y M Array Double NumPoints Little endian Tip X 40 16 NumPoints Y X 16 8 NumPoints PolyLineZM A PolyLineZM consists of one or more parts A part is a connected sequence of two or more points Parts may or may not be connected to one another Parts may or may not intersect one another The following fields are for a PolyLineZM Box The bounding box for the PolyLineZM stored in the order Xmin Ymin Xmax Ymax NumParts The number of parts in the PolyLineZM NumPoints The total number of points for all parts Parts An array of length NumParts Stores for each part the index of its first point in the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each part in the PolyLineZM are stored end to end The points for part 2 follow the points for part 1 and so on The parts array holds the array index of the starting point for each part There is no delimiter in the points array between parts Z Range The minimum and maximum Z values for the PolyLineZM stored in the order Zmin Zmax Z Array An array of length NumPoints The Z values for each part in the PolyLineZM are stored end to end The Z values for part 2 follow the Z values for part 1 and so on There is no delimiter in the Z Array between parts M Range The minimum and maximum measures for the PolyLineZM stored in the order Mmin Mmax Appendix E ESRI shape representation E 11
330. y of length NumParts Stores for each ring the index of its first point in the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each ring in the PolyLineZM are stored end to end The points for ring 2 follow the points for ring 1 and so on The parts array holds the array index of the starting point for each ring There is no delimiter in the points array between rings Z Range The minimum and maximum Z values for the PolyLineZM are stored in the order Zmin Zmax IBM Informix Spatial Data User s Guide Z Array An array of length NumPoints The Z values for each ring in the PolyLineZM are stored end to end The Z values for ring 2 follow the Z values for ring 1 and so on There is no delimiter in the Z value array between rings M Range The minimum and maximum measures for the PolyLineZM stored in the order Mmin Mmax M Array An array of length NumPoints The measures for each ring in the PolyLineZM are stored end to end The measures for ring 2 follow the measures for ring 1 and so on There is no delimiter in the measure array between rings The following are important notes about PolyLineZM shapes e The rings are closed the first and last vertex of a ring must be the same e The order of rings in the points array is not significant The following table shows PolyLineZM byte stream contents Position Field Value Type Number Byte order Byte 0 Shape Typ
331. ygon srsName DEFAULT srsDimension 2 gt lt gm exterior gt lt gml LinearRing gt lt gml posList dimension 2 gt 51 71 21 73 73 36 27 04 71 52 32 87 52 43 31 9 51 71 21 73 lt gml posList gt lt gml LinearRing gt lt gml exterior gt lt gm1 Polygon gt lt gml PolygonMember gt lt gml MultiPolygon gt 1000 The ST_GeomFromKML function The ST_GeomFromKML function takes a KML fragment and returns an ST_Geometry corresponding to the fragment Syntax ST_GeomFromKML km l_string lvarchar Return type Depends on the KML fragment type as shown in the following table Table 8 4 KML fragment to return type mapping KML fragment Return type Point ST_Point LineString ST_LineString Polygon ST_Polygon MultiGeometry plus Point ST_MultiPoint MultiGeometry plus LineString ST_MultiLineString MultiGeometry plus Polygon ST_MultiPolygon Example The geometry_test table contains the INTEGER gid column which uniquely identifies each row and the geom column which stores the geometry CREATE TABLE geometry_test gid INTEGER geom ST_Geometry Chapter 8 Spatial functions 8 45 The following INSERT statements insert the data into the gid and geom columns of the geometry_test table The ST_GeomFromKML function converts the KML text representation of each geometry into its corresponding instantiable subclass INSERT INTO geometry_test VALUES 1 ST_GeomFromKML lt Point gt lt coo
332. yte stream contents Position Field Value Type Number Byte order Byte 0 Shape Type 8 Integer 1 Little endian Byte 4 Box Box Double 4 Little endian Byte 36 NumPoints NumPoints Integer 1 Little endian Byte 40 Points Points Point NumPoints Little endian PolyLine A PolyLine is an ordered set of vertices that consists of one or more parts A part is a connected sequence of two or more points Parts may be connected to and may intersect one another Because this specification does not forbid consecutive points with identical coordinates shapefile readers must handle such cases On the other hand the degenerate zero length parts that might result are not allowed The following fields are for a PolyLine Box The bounding box for the PolyLine stored in the order Xmin Ymin Xmax Ymax NumParts The number of parts in the PolyLine NumPoints The total number of points for all parts Parts An array of length NumParts Stores for each PolyLine the index of its first point in the points array Array indexes are numbered with respect to 0 Points An array of length NumPoints The points for each part in the PolyLine are stored end to end The points for part 2 follow the points for part 1 and so on The parts array holds the array index of the starting point for each part There is no delimiter in the points array between parts The following table shows PolyLine byte stream contents Position Field Value Type Number By

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