User's Manual for Thuban 1.0 - Previous Directory
Contents
1. FARM OTHER UNKNOWN 4 gt 4 j Sort Reverse K Sort Reverse Color Scheme Grey Ramp Fix Border Color Change oe Chapter 5 Layer Classifications The Uniform Distribution option creates a user specified number of groups of ranges such that each range covers equal intervals The minimum and maximum values can automatically be retrieved from the table by clicking Retrieve From Table The stepping is how large each interval is Adjusting this value will automatically recalculate how many groups is appropriate 16 Chapter 5 Layer Classifications Figure 5 5 Uniform Distribution H f Generate Classification ate Uniform Distribution The Quantiles option generates ranges based on the number of items in the table For example by specifying five groups Thuban will generate five groups with appropriate ranges such that 20 of the table data is in each group If it is impossible to generate exact groupings Thuban will issue a warning but allow the user to continue Figure 5 6 Quantiles 17 Chapter 6 Projection Management Projections control how the geographic data is displayed on the screen If multiple layers are loaded into Thuban where the geographic data is in a different projection system then the user must specify a projection for each layer The user must also tell Thuban which projection the map is in This can be the same as the layer2. 6 936 EX POLUM 7 as ht ce i Sa IR a ae 8 4 Layer Managementl ssssssssssessssssessssessssssessssersssesesessesssseseseesesesseseseesesseseseseesesesesesseseseesesessasessesesesseseseesess 9 4 1 LY peSiob aay ers enen Soh aeons ites R eae Eee DA en te Os 9 4 2 9 4 3 Visibility en ee 10 4A DupliCation 10 5 Layer Classifications SESSE 12 9 1 Editing Classi Caton 12 Sells Visible ati adda ie ei ais 13 Ds 5 13 913 Ma WE eee cae 13 9514 Dae 14 5 2 Classes a ee ha ae SR SS 14 6 Projection Management 18 61 a Projection SAA ee as ed spe ee ash 18 6 2 Editing Projection 18 6 3 Importing Exporting 19 7 Table 20 20 7 2 General Functionality Menu Table 21 ED o a e a 21 122 AEE EE E NEES 21 T E E AE E EA E A A 21 EE ES TON R EE T E A T 21 VOM 21 ES Attribute
3. Lables 22 7 3 Le Show 22 JOM LAD A A 22 7 3 3 Unjom ORB RATA 22 ili C T A N E O TE AEE 24 8 1 Add personal extensions via thubanstart py 24 8 2 Writing simple extension Seniore eae e ee E E E E E teed ET 24 8 21 belo World Py EA AE 25 8 2 2 Registering a Command saser n a E E EEE EEE a R R E ES 26 8 2 3 The Th ban contexto A RA A N RAAE RE 26 9 Trouble Shooting iccccsecssesscescesssessvsissseadsoscessencessosssesensassssescesseaseonssssessassousvenosseoudaes sesovessonssedsodessodasceseeessseassosesen A Supported Data Sources Supported Projections issecccccccsserscssssocerovcsessesavescissvsesasedcadsesseessscesedesesssonvesseestsesevedensoaseessesceseseosesevassesocsssssn List of Figures 121 The Mam Window sich tea vee dh 2 2 lSessiOn Into tee et he ee heh ee 4 4 1 Properties Window 9 4 2 Properties ints eA ies isha ee a ee a eee 10 5 1 Properties WAN OW aves tis hack vip 12 5 2 Generate Class 14 5 3 Custom Color A ett eee Ate 15 5 4 Unique Values 15 5 5 Unitorm Distributions a
4. Table Management Thuban distinguishes two different types of tables Attribute tables which belong to a layer and normal data tables Both provide the same general functionality with the difference that actions on an attribute table might also effect the map display 7 1 Table View Figure 7 1 Table View Selection 0 05 Replace Selection FNODE_ TNODE_ LPOLY_ RPOLY_ LENGTH RDLINE_ E 146 0156000 i 146 0 031000 4 146 0 161000 146 0 039000 146 0 121000 146 0 040000 146 087000 146 0 110000 10 146 0 001000 Export Export Selection 839 rows 163 selected 9 columns GS a Thuban provides a standard dialog to display table contents the Table View The view has five sections The title selections the table grid export functions and the status bar The title bar identifies the table with its name The selections box let the user perform simple analysis on the data based on comparisons The first choice must be a field identifier of the table the second choice determines the type of comparison The third choice can be either a specific value interpreted as numerical or string depending on the type of the first field or a second field identifier Thus you can perform analysis like selecting all records where population gt 10000 or cars_per_inhabitant lt bikes_pe
5. Update Only a projection that comes from a file can be updated so if the current layer s projection is selected Update will be disabled Add to List adds the 18 Chapter 6 Projection Management projection to the list of available projections as a new entry and thus makes it available to future Thuban sessions Clicking New will create an entirely new empty projection The Remove button will permanently remove a projection from the list of available projections To apply the selected projection to the map the user can click either Try or OK Try will not close the dialog box allowing the user to see how the projeciton changes the map Revert will undo the last projection applied to the map OK will commit the changes and close the dialog The user will be unable to undo the changes Close simply closes the dialog box If no selection has been applied with Try the selection will not be applied to the map 6 3 Importing Exporting Projections The projections that appear in the list of available projections can be exported to another file that the user chooses By selecting one or more projections and clicking Export the user will be able to select a file in which to store those projections The file can then be distributed to other Thuban users To import a projection file the user can click Import The imported projections are added to the list and are then available to the current session and any future Thuban sessions 19 Chapter 7
6. the GDAL library Thuban supports numerous raster file formats see GDAL format list http www remotesensing org gdal formats_list html for details Most commonly used is the T F F GeoTIFF format Raster maps are provided as TIFF images with an additional world file storing the geographic reference usually with an extension tfw 29 Appendix Supported Projections The following types of projections are directly support by Thuban The specific values for each are provided by the user to create custom projections Thuban comes with predefined projections which are available through the Projections dialog e Geographic e Ellipsoid Source Data either Degrees or Radians Lambert Conic Conformal e Ellipsoid 6 Latitude of lst standard parallel 6 Latitude of 2nd standard parallel e Central Meridian e Latitude of Origin e False Easting meters e False Northing meters Transverse Mercator e Ellipsoid Latitudeof origin Longitudeat central meridian e Scale Factorat central meridian e False Easting meters e False Northing meters Universal Transverse Mercator Ellipsoid Zone can be guessed appling the Propose button e Southern Hemisphere flag Thuban comes with a sample set of map projections for various European countries Apart from the basic projection they differ especially in their parameterization Belgium Datum 1972 Lambert Conic Conform
7. the second part of this example consist of the plain statements to create a new Command and to add it to the menu By convention it looks for a menu registered as extensions to insert the new command If it does not exist yet it gets created It is advisable to copy this code for any of your extensions 8 2 3 The Thuban context A registered command that is called always receives the Thuban context This instance provides our method with hook references to all important components of the Thuban application In the example hello_world py our function uses the mainwindow component which offers a method to raise a message dialog In total there are three hooks application This object is the instance of the Thuban Application class Except maybe for loading or savinf sessions you will not need this object for a simple extension See Thuban UI application py for the API e session The instance of the current session It manages the sessions map and tables You can set and remove the map or tables In may also get the map object However you should know that internally it is already prepared to handle many maps Therfore currently you would always receive a list with exactlty one element In the future if there are more than one map you will not know which one is the currently display one and therefore you should use the mainwindow as hook to find the currently displayed map See Thuban Model session py for the API mainwindo
8. Properties Window Li ox Title Roads Type Classification Field LENGTH x Data Type Decimal Generate Class Add Move Up Move Down Edit Symbol Visible Remove Try Revert Close Figure 4 2 Properties Window Layer Properties Iceland Image o o x Title Image Type Image Ty Revert OK Close 4 3 Visibility Sometimes it is not desirable to view all layers at the same time Some layers may take a long time to draw and so while navigating around the map the user may not want to wait for the map to redraw all the layers each time the map is changed Each layer can be independently turned on or off using the Layer Show Layer Hide options respectively 10 Chapter 4 Layer Management 4 4 Duplication Layers and all their properties including classifications can be duplicated using Layer Duplicate Duplicating a layer is useful if the user wishes to model a layer in several different ways Even though the layers overlap by carefully selecting the shape properties it is possible to display several pieces of information at once For example one copy of a roads layer may be classified on a length property and another copy may be classified on a type property If the length property was expressed with color and the type property expressed with line thickness then it would be possible to view both classifications by placing the type proper
9. User s Manual for Thuban 1 0 Jonathan Coles Jan Oliver Wagner Frank Koormann User s Manual for Thuban 1 0 by Jonathan Coles Jan Oliver Wagner and Frank Koormann Copyright 2003 Intevation GmbH Revision History Revision 1 0 2 29 Aug 2003 Corresponds to Thuban development release 0 8 1 New chapter on extensions Revision 1 0 1 08 Aug 2003 Corresponds to Thuban development release 0 8 1 Table of Contents 1 INtroduction sssssssrsssesssersessesessseesessssesesessessesesssesseseesesssensesessesssseseseesasessesasessesessosesessesessesesessosessessesseseeses 1 1 132 The Window 1 2 Session Managemen escoi ar inai nE nE EEE NEE EEE EE EEEE OENE NE E 3 9 1 Startins a New E E E E i a E E E E 3 2 2 SESSION sicir ierre ai ia a OEE Po STESS thes 3 2 3 Saving ASESSION eE RES i E E EEEE ise eee eae Seeded VSEE EEO 3 2 4 The Sessio Info Treen 3 3 tt e ESNEKIEN NENE EEOSE SEEREN iai 5 3 1 Adding and Removing 5 5 3 2 NAVIGAU OM 5 3 3 Object Identification E E E E A ae eed a sees 6 9 4 Object Labeling 6 3 3
10. al Gauss Boaga Zone 1 Italy Transverse Mercartor Gauss Krueger Zone 2 Germany Transverse Mercartor Reseau Geodesique Francaise France Lambert Conic Conformal 30 Appendix Supported Projections UK National Grid United Kingdom Transverse Mercartor Thuban uses the comprehensive PROJ library for projections PROJ provides more than the four commonly used projections described above If needed Thuban can be easily extended to a new projection covered by PROJ 31
11. d need ie aes 16 9 6 17 6 1 Projection WINdOW pis 18 20 9 2 JOM EE Lt tt eel ee 22 921 Error Dialog e e deters es 27 Chapter 1 Introduction Thuban is an interactive geographic data viewer It has been developed because there was no simple interactive viewer for geographic information available as Free Software Thuban is written in Python and C and uses the wxWindows library allowing it to run on many different platforms including GNU Linux and Windows Geographic data viewers are a necessary tool as they allow one to get a visual impression of the positional relationship of the information that may not be apparent from simple inspection of the data values themselves Thuban allows the user to create a session that displays geographic data and then explore that data through navigation and manipulation of how it is drawn The results can then be saved or printed Thuban arranges a session in a hierarchy A session contains a map which consists of layers Each layer represents one kind of data set For instance there may be a layer for roads and another layer for buildings These layers can either be vector shapes or images 1 1 Installation Thuban is actively supported under Debian Testing sarge RedHat 7 2 and Windows 2000 Thuban depends on the follo
12. duces into some oppportunities how to add and handle extra functionality developed by your own or third parties 8 1 Add personal extensions via thubanstart py After Thuban has been started for the first time a directory thuban is created within your home directory There you can add a file thubanstart py which will be imported by Thuban at start up It is recommended to add only import statements to this file to keep the actual code of extensions separate The modules to import must either be found though the environment variable PYTHONPATH or directly be placed into the thuban directory As an example copy the file examples simple_extensions hello_world py of the Thuban source code into the thuban directory of your home directory Now add add the statement import hello_world to the file thubanstart py and run Thuban You will notice an additional menu Extensions where the new item for the Hello World extension is placed select it to see the Hello World message 8 2 Writing simple extensions Writing an extension for Thuban basically means to implement the extra functionality in Python with all of the Thuban classes methods and variables available All classes and their methods are documented in the source code see their doc strings Here is an example from Thuban Model layer py that describes some of the methods of a Layer object class BaseLayer TitledObject Modifiable class for the layers def __ini
13. huban import _ Thuban has named commands which can be registered in the central instance registry from Thuban UI command import registry Command The instance of the main menu of the Thuban application See Thuban UI menu py for the API of the Menu class from Thuban UI mainwindow import main_menu def hello_world_dialog context Just raise a simple dialog to greet the world context The Thuban context un context mainwindow RunMessageBox _ Hello World _ Hello World create a new command and register it 25 Chapter 8 Extensions registry Add Command hello_world _ Hello World hello_world_dialog helptext _ Welcom veryone on this planet find the extensions menu create it anew if not found extensions_menu main_menu find_menu extensions if extensions_menu is None extensions _menu main_menu InsertMenu extensions _ E amp xtensions finally bind the new command with an entry in the extensions menu extensions_menu InsertItem hello_world 8 2 2 Registering a Command Mainly our new function has to be registered to the Thuban framework in order to connect it to the menu A registered command can also be connected to e g a toolbar button The instances and classes for this are imported at the beginning Any code not inside a method or class is directly executed when the source code module is imported Therefore
14. infinity like this 00 Field types can also be of type Decimal They represent any rational number and can be used in ranges as well 5 1 4 Label By default the text that is displayed for a group in the legend is the value for that group The label can substitute a more descriptive term in the legend 5 2 Generating Classes Figure 5 2 Generate Class Generate Classification xj Field LENGTH Data Type Decimal Generate Quantiles from T able Unique Values Uniform Distribution Quantiles from Table Number of Classes 1 24 Color Scheme Grey Ramp v oe Creating a classification by hand can be tedious Thuban therefore provides a means of generating an entire classification at once while still giving the user control over how it appears Clicking Generate Class opens the Generate Classification dialog Under the Generate pull down there are at most three different ways to generate classifications Unique Values Uniform Distribution and Quantiles Some options may not be available 14 Chapter 5 Layer Classifications if the data type for the field does not support them For instance Uniform Distribution doesn t make sense for a Text field For every way of generating a classification a color scheme must be selected Thuban provides several different color schemes that affect how the group properties change over the classification It may be desirable that only certain properties change
15. ing with Thuban It displays many of the internal values for the session map and layers It can be opened from File Session Tree Chapter 3 Map Management The map consists of a number of layers where each layer represents a different type of data set By interacting with the map the user can visually explore the data The map can have a name that will appear in the Thuban title bar The map name can be changed using Map gt Rename I x Map Title iceland map Cancel 3 1 Adding and Removing Layers There are two types of layers that can be added to a map Shape layers and image layers Shape layers are stored in Shapefile format a widely used file format for storing geographic objects These files have the extension shp Associated with the shape file is a database file which stores attributes for each shape in the Shape file This file in dBase format has the extension dbf Both files must have the same base name For example if there is a shape file named roads shp there must also be a file roads dbf Shape layers can be added to the map with Map Add Layer Initially only the shp files are shown which is enough for the selection However if you switch to display all files and select one of the associated files e g dbf Thuban will recognize the base name and load the corresponding Shape file The file dialog for Shape files allows to select multiple files Use the shift button
16. le view is opened 7 2 2 Close The Table Close item raises a dialog listing the currently open data tables loaded via Table Open Selected tables are dereferenced on confirmation Since tables are opened read only the contents of the tables are not affected Any open views of the tables are closed as well Tables used in a join cannot be closed 7 2 3 Rename Table Rename changes the table title 7 2 4 Show The Table Show item raises a list of available tables explicitly loaded attribute tables results of a join Selected tables are show in tables views on OK 21 Chapter 7 Table Management 7 2 5 Join Figure 7 2 Join Tables Table v Table other_roads Field Field Outer Join preserves left table records The Table Join item raises dialog to specify the two tables to be joined The join results in a new table named Join of left table and right table The dialog lets you select the two tables to be joined and the two fields the join has to be performed on By default the new table contains only those records which are matched by the join If you want to preserve the records of the left table you can perform an outer join The fields from the right table for records not matched by the join are filled with None in this case 7 3 Attribute Tables To clearly separate between both types of tables da
17. n If a session is already loaded and has been modified without being saved a prompt will ask if the current session should be saved 2 3 Saving a Session A session can be saved from File Save Session A dialog box will open allowing the user to browse the file system and select a place to save the session Thuban sessions should be saved under name ending in If the file already exists the user will be prompted to save under a different name or overwrite the existing file Chapter 2 Session Management 2 4 The Session Info Tree Figure 2 1 Session Info Tree Session Session Thuban sample session Filename D cygwinhome user build T huban 0 8 thuban D ata iceland_sample_raster thuban Unmodified Map Iceland map Extent lat lon 24 5496 63 2823 13 4914 66 5656 Extent projected 322003 7 0217 7e 006 876022 7 4028e 006 Projection proj utm zone 27 ellps clrk66 Layer cultural_landmark point Filename D cygwinhome userS build T huban 0 8 thuban D ata iceland cultural_landmark point shp Shown Shapes 34 Extent lat lon 23 8056 63 4049 15 1227 66 3646 Shapetype Point Projection proj latlong to_meter 0 01 7453 ellps clrk66 Classification DEFAULT B Line Color 0 000 0 000 0 000 o Line Width 1 i 0 Fill 1 000 1 000 0 000 Layer toads line Layer political Layer Iceland Image The session info tree is primarily intended for developers work
18. org bugtracker html More information about the system is available from Help About box This should also be included in the bug report Figure 9 1 Error Dialog Thuban Internal Error ES unhandled exception occurred please report to http thuban intevation org bugtracker html Traceback most recent call last File thuban py line 26 in Thuban UI main maint File Thuban UI main py line 26 main app Thuban4pplication 0 File C wx versions wxPython 2 4 0 6 wxPython we py line 1821 _weStart self File Thuban U application py line 62 in Onlnit self create_session File Thuban UI application py line 190 create_session self SetSession create_empty_session File Thuban Model session py line 384 in create_empty_session gt OK 27 Chapter 9 Trouble Shooting 28 Appendix Supported Data Sources Shapefile The Shapefile format has become a standard format for saving geographic vector information It supports polygons lines and points Technical Specification http www esri com library whitepapers pdfs shapefile pdf dBase file dBase files are used to store the attributes for each layer This is closely associated with the Shapefile format For detailed specifications on the correct format of a dBase file used with Thuban please see the Technical Specification for the Shapefile format above Raster files Binding
19. over the classification If the shape type is a polygon or a point then the Fix Border Color option will be available This allows the user to select a border color for all classification groups It is also possible to create a custom color scheme Selecting this option will display two symbols the one of the left has the properties of the first group and the one on the right has the properties of the last group Thuban will interpolate between these two properties to generate the other groups Figure 5 3 Custom Color Scheme Generate Classification gt Field LENGTH Data Type Decimal Generate Quantiles from Table Apply to Range 0 001 1 994 Retrieve from Table Number of Classes Color Scheme Custom Ramp X Start End gt gt a Change lt Change ome The Unique Values option lets the user select specific values that appear in the table Clicking Retrieve From Table searches the table for all unique values and displays them in the list on the left Items can be selected and moved to the list on the right Each list can be sorted or reversed for easier searching The classification that is generated will be in the same order as the list on the right 15 Figure 5 4 Unique Values Generate Classification Field CLPTLABEL Data Type Text Generate Unique Values Retrieve From Table Available Use HUT LIGHTHOUSE BUILDING RUINS
20. pen it again use Map Legend The legend is also dockable which means that it can be detached from the main window by clicking on the small button next to the close button It can be attached by clicking the same button again The status bar displays different information depending on the current context If the user is selecting an item from the menu then the status bar will display a short help message indicating what each menu item is for If the user has a tool selected then the position of the cursor on the map is displayed The tool bar provides quick access to the commonly needed tools By hovering over each button the user can see a short messages describing what the tool does The tools provided are Zoom In Zoom Out Pan Full Extent Full Layer Extent Full Shape Extent Identify and Label Each of the tools will be explained in further detail later in the manual Chapter 2 Session Management 2 1 Starting a New Session A new session be started from File New Session If a session is already loaded and has been modified without being saved a prompt will ask if the current session should be saved A new session consists of an empty map with no layers and no tables 2 2 Opening a Session A session can be opened from File Open Session A dialog box will open allowing the user to browse for a Thuban Session file Thuban session files end with Selecting a file a clicking OK will load the session into Thuba
21. played with a small graphic Polygon layers appear as rectangles lines appear as curved lines and points appear as circles Along the top of the legend is a toolbar which allows quick access to some of the layer manipulation options under Map The Move Layer to Top tool Bl raises the selected layer to the top of the map 12 The Move Layer Up tool raises the selected layer one level The Move Layer Down tool lowers the selected layer one level The Move Layer to Bottom tool lowers the selected layer to the bottom of the map The Visible tool shows the selected layer in the map if it was hidden The Invisible tool gt hides the selected layer in the map The Properties tool al opens the layer s properties dialog box Double clicking on a layer or a group of a layer will open the properties dialog for that layer Along the bottom of the legend is the scalebar The scalebar will be available if there are any layers and the map has a projection set 3 6 Exporting Under Windows maps can be exported in Enhanced Metafile format wmf from Map gt Export for use in reports presentations or further modification The current map view legend and if available scalebar are Chapter 3 Map Management exported Under other platforms this option is not available Clicking this menu item open a file selection dialog that lets the user select a location to export the map 3 7 Printing The map can be prin
22. r_inhabitant note that the field names are only explanatory the dBase files allow only 11 character field names Selections can be combined either by applying a selection only on a previously selected set of records or by adding the results of a selection to a previous set The default is that a selection replaces earlier results 20 Chapter 7 Table Management The table grid shows the contents of the table one record per row with highlighted selection results Columns and rows can be resized The contents of a table can be exported into a file either dBase format DBF or comma separated values CSV The Export button raises a file dialog to specify a path and file name the export type is determined by the file extension either dbf or csv The Export Selection button works similarly but exports only the selected records The Close button closes the table view window This is different from the menu item Table Close which unloads the table from Thuban The status bar displays some statistics about the table and optional selection results 7 2 General Functionality Menu Table The general functions affect all tables open in Thuban Attribute tables are considered here as normal data tables with the exception that they cannot be closed 7 2 1 Open The Table Open item raises a file dialog to let you select a dBase file from the file system to be loaded into Thuban read only On OK the selected file is loaded and a tab
23. s or a different projection in which case the layers are reprojected into that space The map projection can be set using Map Projection and the layer projection can be set using Layer Projection Figure 6 1 Projection Window 815 Available Projections Edit lt None gt UTM Zone 27 Belgian Datum 1972 NN Gauss Boaga Zone 1 Projection Universal Transverse Mercator Add to List Gauss Krueger Zone 2 Germany Ellipsoid Clarke 1866 z Reseau Geodesique Francaise Update UK National Grid Remove Zone 27 ET Propose Southern Hemisphere Projection File defaults proj Ty OK Close Thuban is distributed with sample collection of projections The user can create new projections and make them available to all future Thuban sessions They may also be exported and imported so that custom projections can be distributed 6 1 Selecting a Projection The available projections are listed on the left If the layer or map already has a projection it will initially be highlighted and will end with current Selecting lt None gt will cause Thuban to use the data as it appears in the source file and will not use a projection 6 2 Editing a Projection Whenever a projection is selected from the list its properties are displayed on the right These properties can be changed and the changes saved to the selected projection using
24. ser must first select a field to classify on New groups can be added to the classification with the Add button To apply the changes to the map the user can click either Try or OK Try will not close the dialog box allowing the user to see how the classification changes the map Revert will undo the last classification applied to the map OK will commit the changes and close the dialog The user will be unable to undo the changes Close simply closes the dialog box If any changes have not been applied with Try the changes will not be applied to the map 12 Chapter 5 Layer Classifications Figure 5 1 Properties Window Layer Properties Roads Oj x Title Roads Type are Classification Field LENGTH Data Decimal Generate Class Add short Move Up 0 73821 1968 1 1968 1 59541 Move Down 1 59541 994 Very long Edit Symbol Remove Try Revert Close The order of groups in the classification is significant except for the DEFAULT group which remains at the top When shapes are matched against groups the matching begins at the first group after the DEFAULT group so that groups higher in the list will be checked first Matching for a given shape will stop at the first group that matches The user can use Move Up and Move Down to change the order of the groups The DEFAULT group will alwa
25. t__ self title visible True projection None TInitialize the layer titl the titl visible boolean If true the layer is visible TitledObject __init__ self title Modifiable __init__ self self visible visible self projection projection def Visible self Return true if layer is visible return self visible 24 Chapter 8 Extensions def SetVisible self visible Set the layer s visibility self visible visible self issue LAYER_VISIBILITY_CHANGI El D self def HasClassification self Determine if this layer support classifications This example intends to give you an impression of the source code level documentation You have to make yourself familiar with the Python programming language to understand some special code elements 8 2 1 hello_world py Traditionally the first example should welcome the world Most of the code handles the frame for integrating a menu item into Thuban while the actual raising of a message is done in a single line Copyright C 2003 by Intevation GmbH Authors Jan Oliver Wagner lt jan intevation de gt This program is free software under the GPL gt v2 Read the file COPYING coming with Thuban for details Extend Thuban with a sample Hello World to demonstrate simple extensions ww __version__ SRevision 1 20 5 use _ already now for all strings that may later be translated from T
26. ta and attribute Thuban provides functionality regarding the attribute tables under the Layer menu 7 3 1 Show Table Layer Show Table opens the attribute table of the currently active layer in a table view In addition to the functionality described above selections affect also the map display objects related to selected records are highlighted 7 3 2 Join Table Unlike the join described above the join does not result in a new table The attribute table of the currently active layer is the left table and other tables are joined to this table The results of the join are available for classification As a consequence the join cannot result in fewer records than the source attribute table The user is warned if the right table does not fulfill this constraint An outer join must be used in such cases 22 Chapter 7 Table Management 7 3 3 Unjoin Table As said above a normal table cannot be closed while it is still used in a join While the joined table resulting from a join of normal tables can be simply closed and thereby dereferencing the source tables this is not possible for attribute tables Hence joins on attribute tables must be solved explicitly This is what the Layer Unjoin Table item is used for The last join for the currently active layer is solved 23 Chapter 8 Extensions Thuban is designed to be extensible The term Extension is used as a general term for anything that extends Thuban This chapter intro
27. ted using Map Print The current map view legend and if available scalebar printed A standard printing dialog will open allowing the user to configure the printer This dialog will differ depending on which platform Thuban is running Chapter 4 Layer Management 4 1 Types of Layers There are two types of layers supported by Thuban shape layers and image layers Shape layers consist of vector based shapes with geo referenced coordinates There are three types of supported shapes polygons lines arc and points Image layers can be any image file format supported by the Geo spatial Data Abstraction Library GDAL The images must have geographic coordinate data either embedded within the file or in a separate file that is in the same directory as the image file GeoTIFF files work very well with Thuban and were designed specifically to be image layers in GIS programs All actions in the Layer menu act on the currently selected layer in the legend 4 2 Properties To view the properties for a layer it must first be selected in the legend The menu option Layer Properties opens a dialog that displays a layer s properties All layers have a title which can be modified in the text field provided The type of layer is also shows If the type is a type of shape polygon arc point the classification table will be shown Image layers have no other properties other than title and type Chapter 4 Layer Management Figure 4 1
28. together with the left mouse button to extend the selection Image layers can be added to the map with gt Image Layer It is important to select a valid image file that has geographic data associated with it The data can be embedded in the file itself or in another file If geographic information cannot be found Thuban will report an error 3 2 Navigation The map can be explored by using the navigation tools available on the tool bar or from the Map menu The ZoomIn tool enlarges a region of the map Clicking once the map will double the magnification and center the map on the point that was clicked Clicking and dragging selects a region that will be enlarged to fit the window Chapter 3 Map Management The ZoomOut tool 2 shrinks the map so that larger region is visible A single click reduces magnification by a factor of two Clicking and dragging selects a box such that the current contents of the window will be scaled to fit into that box The Pan tool allows the user to move the map around by clicking and dragging al The Full Extent tool rescales the viewable region so that the entire map is visible The Full Layer Extent tool S rescales the viewable region so that the currently selected layer fits within the window If no layer is selected this button will be disabled The Full Shape Extent tool x rescales the viewable region so that the currently selected shape fi
29. ts within the window If the shape is a point it is centered and the map is zoomed all the way in If no shape is selected this button will be disabled This feature is especially helpful when identifying an object related to a selected record in a tableview see below 3 3 Object Identification 2 Objects on the map can be identified using the Identify tool x Clicking on an object selects that object and opens a dialog which shows all the table attributes for that object Any current selection is lost Objects on the map are typically shapes and this document will often refer to objects as shapes 3 4 Object Labeling Objects can be labeled using the Label tool N Clicking on an object selects that object and opens a dialog which displays the table attributes for that object An attribute can be selected to be the label on the map The label will be placed at the center of the shape Clicking on an object that already has a label will remove the label Chapter 3 Map Management 3 5 The Legend 8 27 Cultural Landmarks DEFAULT 8 27 Roads ey DEFAULT 27 DEFAULT amp I celand Image E 0 The Legend provides overview of the layers in the map Layers that appear higher in the legend will appear closer to the user If a layer supports classification currently only shape layers have this feature then the classification groups will be shown below each layer The properties for each group are also dis
30. ty copy over the length property copy Il Chapter 5 Layer Classifications A layer classification is a way of assigning drawing properties to groups of shapes based on attributes stored in the layer s table Only layer s with shapes can have a classification image layers cannot be classified A classification consists of a number of groups each group having a value or range of values to match against and symbol properties which control how a shape is drawn on the map The user selects which field in the table is used by the classification and when the map is drawn the value for that field for each shape is compared with each group s value The properties of the first group to match are used to draw the shape This allows the user to get a visual impression of not only how the data is laid out but also what kind of data lies where A layer always has a classification When a new layer is added to the map a default classification is created with the DEFAULT group This group cannot be removed but can be hidden see below Every shape in the layer regardless of its attributes will match this group if no other group matches 5 1 Editing Classifications A layer s classification can be modified under the properties dialog Layer Properties The layer s classification field can be set to None which simply assigns a DEFAULT group to the classification No new groups can be added to the classification if the field is None The u
31. w The mainwindow object is central to manage various GUI things such as the Legend sub window Most notably you get access to the canvas which is the window part where the map is drawn The canvas knows which map it currently draws and therefore you get the current map via context mainwindow canvas Map See Thuban UI mainwindow py for the API 26 Chapter 9 Trouble Shooting Here are a few problems that users have encountered when first using Thuban After adding two or more layers nothing is drawn in the map window This is probably because the layers have different projections Projections must be set on all layers and on the map itself if the layers projections are different Thuban crashes on startup with the error NameError global name False is not defined True and False were only introduced in Python 2 2 1 Thuban depends on at least Python 2 2 1 After compiling Thuban Thuban crashes with an error similar to ImportError usr local lib thuban Thuban Lib wxproj so undefined symbol __gxx_personality_v0 Thuban depends the wx Windows library If Thuban is compiled with an incompatible version of the compiler than wx Windows was compiled with this error may occur Try compiling with a different version of the compiler If an error occurs Thuban will display a dialog indicating the error before closing The text should be copied and reported to the Intevation bugtracker http thuban intevation
32. wing packages These packages can also be found on Thuban Download site http thuban intevation org download html Python 2 2 1 http www python org wx Windows 2 4 http www wxwindows org wxPython 2 4 http www wxpython org proj 4 4 5 Projection Library http www remotesensing org proj GDAL 1 1 8 http www remotesensing org gdal SQLite 2 8 3 http www hwaci com sw sqlite PySQLite 0 4 3 nttp pysqlite sourceforge net Along with the source codes the download page also offers full installation packages for Debian Windows and RPM based systems Mandrake RedHat SuSE etc Chapter 1 Introduction 1 2 The Main Window Figure 1 1 The Main Window lolx File Map Layer Table Help 8 27 Cultural Landmarks DEFAULT 8 27 Roads DEFAULT Bon DEFAULT 27 Iceland Image 4 59 Window 768925 5685 7080470 674 Status Bar The map window shows the current state of the map and is where the user can interact with the map using the tools The legend on the left displays a list of the current layers and any visible classification groups In the example each shape layer has a default classification which specifies how the shapes in each layer are drawn Layers that are higher in the list appear closer to the user The legend can be closed by clicking on the small X in the upper right hand region of the legend To o
33. ys match a shape that hasn t matched another group 5 1 1 Visible The Visible column has check boxes that determine whether a classification group will be displayed in the legend This is useful if the user knows that the groups completely cover the data set and don t want the DEFAULT group to be displayed in the legend and on a printout 5 1 2 Symbols Each type of shape has its own type of symbol Thuban supports three types of shapes polygons lines and points Polygons and points have outline and fill color while lines have only line color Each group has associated symbol properties To edit the symbol properties for a group the user can double click on the Symbol column or select a group and click the Edit Symbol button 13 Chapter 5 Layer Classifications 5 1 3 Value The Value column of the classification table is the value that will be matched when the map is being drawn The type of data that can entered into this field depends on the type of data of the classification field If the field is of type Text anything entered into the field is valid The text will be compared literally to the value of the shape attribute including case sensitivity If the type is Integer then any valid integer may be entered In addition with special syntax a range of values can be entered A range from start to end inclusive is specified like this start end The exclusive range is specified like this start end Ranges can include
Download Pdf Manuals
Related Search