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1. 28 DDIM AD BI isi 28 Culbire and Sersmirc SDF TH CS riranna r E oce mrt pie pbsebibibiPIbIbILMPADRPIDULIDU EEE E MUR LS E E 28 Unknown and Undefined CRS in Petrosys Data ccccscscccccsccnscnnensceneseneeee seen na saeua sua ahud aan aaa an 29 Assigning CRS to Existing Petrosys FICS vieseseesedcdudududncessdesenideadatenadads FRE E RIRORORSRNePes sse Pa eu ae Puae s KindgUs 29 Petrosys Coordinate Reference Systems CRS 1 of 54 Projection Types from Older Versions of Petrosys ssssseeeeen mnn 30 Submittihg CRS PIO DOSS vii teo tuaei Dutopeck e meia beveled dat ald niet a ce itia gita et d cR d 31 Updating your CRSIDSTPIEIOS Se ssisep etes Eon Me cae ada RU d Eaa RR VIRA UNO e PN DE Rd aste dee RE TER ME EE 32 Coordinate Reference Systems Tools cer sereeoeee hee h enhn hhn hh nnn nnn 33 CDnoosind a EXIST ORG RS vacate hain a dc ie Fiona acti eor sta MER rU Ped aO api 34 Defining a NEW CRS istud scc rer Pepe ate tn euo RENT Erbe ECL REI enema tee 35 New ProjCRS based on an existing GeogCRS issesesesesseeseses een hush huh a haa aa EANNA ELE EEA 35 ABSENT I Tr 35 New GeogCRS based on an existing Datum eiesesesesese eese essen hau a sese su sese sa sa sa sa su ausa auda danda 36 360g R5 Mans MAON EGI O assise vas rU A diis MAMMA DEMENS CIIM CI UI NI 37 DERING NEW Trans tTOrI IS esy EM 37
2. Coordinate Reference Systems Background Petrosys Coordinate Reference Systems CRS 3 of 54 Coordinate Reference Systems There are no survey markers in the ocean To work with petroleum EP information we are totally dependent on our knowledge of present and past survey references and techniques geomatics Coordinate Reference Systems CRS define the surveying and geomatics parameters on the basis of which specific location data have been measured and displayed They allow us to relate observations made in different surveys and at different times to one another as well as to the physical Earth in a systematic way If your work involved data that was all acquired using current technology over a small area by reliable contractors and based on the work of an established national mapping standard then you might just be able to work without thinking about CRS In Petroleum exploration and production we are always interested in the inclusion of earlier work or work by other companies in our interpretations and maps An understanding of CRS is therefore essential for anyone working with EP data What is a Coordinate Reference System A coordinate is a definition of one location typically expressed in a geographic latitude longitude and elevation or a projected easting northing elevation form A coordinate reference system is a collection of knowledge that defines the measurement framework in which a coordinate
3. Texas crih Central e AAH NAI 7 Texas Rrrin Centra irl 7 jilt MADEJ Texas uult z rj NADJ 7 Tesas South fill HADES Tc SoutF Cantral Hades Texas SoutF Cantal AUS Aa Te Mere TED Geograrhic CRS Meme Projector GEonrapric CRS Fr tin Close Hew 2x cance peg As long as you have the appropriate privileges you can create projected CRS both at the Project and the Site level The CRS File window notes where the CRS will ultimately be stored If you are just experimenting with some parameters then you should restrict your projected CRS to being at the project level On the other hand if the analysis is part of a long term corporate interpretation or the mapping is an extension of existing corporate standards then you may want to define the projected CRS at the site level When assigning a name take into account existing standards both at the EPSG and your company level Pick the geographic CRS within which your ProjCRS is to be defined This establishes the geodetic datum In general you would use the established GeogCRS for other work in this project unless there is a really good reason not to Now pick the projection to be applied within this GeogCRS to create your ProjCRS The list of existing projections is displayed You can click on the column headers to sort the list for easier selection For example if you are looking for Lambert projections click on
4. Indonesia ID74 DGN95 New Zealand NZGD49 NZGD2000 Malaysia various GDM2000 South America various SIRGAS2000 Argentina has it s own POSGAR98 datum The EPSG database includes cross references from locations to commonly used datums along with historical information on the evolution of the relationship This information is displayed in the detailed information windows in the various Petrosys CRS picking tools and can be browsed using the Petrosys EPSG CRS browser on the Internet Petrosys Coordinate Reference Systems CRS 10 of 54 GeogCRS Ellipsoid or Spheroid An ellipsoid is simply a flattened sphere The shape of the Earth is closer to an ellipsoid than to a sphere The ellipsoid or spheroid associated with a GeogCRS is an estimate of the best fit ellipsoid for a particular model of the Earth s shape without precisely locating that ellipsoid relative to the planet As the Earth is not an exact ellipsoid a given ellipsoid is an approximation that will be a better fit on some parts of the Earth than on others As a result different ellipsoids are used in different parts of the World Individual ellipsoids don t necessarily claim to be truer than others they simply work better in specific parts of the Earth In Petrosys the terms ellipsoid and spheroid are used interchangeably The ellipsoid can be defined in one of two ways 1 The semi major and semi minor axis can be specified as lengths These are the radi
5. pick a file list containing the names af the files you want ta convert The convert project coordinates option should NOT in general be used in upgrading projects from pre CRS to post CRS versions of Petrosys as it is slower and may modify the coordinate data itself in other words it will apply a datum conversion if the project default datum or the datums in existing files are different to the output datum and an easting northing conversion of projected coordinates if there is a mismatch in the projected CRS Grid origin and node locations will change when coordinates are converted The resample grid option can be used to ensure that the new grid reflects the underlying data in the same way as the version in the original CRS albeit with different grid cell locations Petrosys Coordinate Reference Systems CRS 54 of 54
6. 1380 GRS 1380 Bessel 1841 International 1824 Clarke 1666 Krassowsky 1940 Neu Neu Topographic mapping SE Base on Porto Santo island Origin and orientation constrained to those Origin description of the 1335 adjustment Data source EPSG Close New Save Save As Delete You should avoid adding new datums unless you are confident that they are really unique In general this will be in situations where you are working with historical data from locations that have not had a lot of recent petroleum EP activity Petrosys Coordinate Reference Systems CRS 44 of 54 ProjCRS Editor GeogCRS Ellipsoids Projected CRS Editor Geographic CRS New Datum New Ellipsoid New A new ellipsoid or spheroid needs to be registered in the rare cases where a GeogCRS datum is based on an ellipsoid not yet recorded in EPSG Before creating a new ellpsoid or spheroid please check carefully that none of the existing ellipsoids may be the one that you want but under a slight variant of the name or with the numeric encoding in a different format such as using the flattening rather than the semi minor axis Creation of an ellipsoid is triggered using the New button against the Ellipsoid field of the datum editor W Projected CRS Editor a OX E Geographic CRS Editor mx m f Datum Editor mx Ellipsoid Editor mx Q VE e Y 2 Owner e GRS 1967 e GRS 1967 SA
7. Petrosys CRS for Unknown applied when used in a map or computation Assigning CRS to Existing Petrosys Files CRS can be assigned to existing Petrosys files using one of the following 1 Edit Header options in the editors specific to the file type 2 File Maintain CRS Assign CRS to files 3 File Maintain CRS Convert project coordinates See the help topic Setting CRS in Existing Files for more information on the last two options Petrosys Coordinate Reference Systems CRS 29 of 54 Projection Types from Older Versions of Petrosys Prior to Petrosys 16 alternate names and codes were used for projection types When these older projection types are encountered they are replaced with the EPSG projection types as shown here This table is still under review LAMBERTI LAMBERT2 MERCATOR TM STEREOGRAPHIC STEREOGRAPHIC polar NZMG HOTINE OBLIQUE MERCATOR OBLIQUE MERCATOR POLYCONIC ALBERS1 ALBERS2 AZ EQ DIST NO PROJECTION EPSG LAMBERT 1SP CODE 9801U EPSG LAMBERT 2SP CODE 9802U EPSG MERCATOR 2SP CODE 9805U EPSG TRANSVERSE MERCATOR CODE 9807U EPSG STEREOGRAPHIC CODE 9809U EPSG POLAR STEREOGRAPHIC A 9810U EPSG NZMG CODE 9811U EPSG HOTINE OBL MERCATOR CODE 9812U EPSG OBLIQUE MERCATOR CODE 9815U EPSG AMER POLYCONIC CODE 9818U EPSG ALBERS EQ AREA CODE 9822U EPSG ALBERS EQ AREA CODE 9822U EPSG AZ EQ DIST CODE 9831U EPSG PLATE CARREE CODE 9825U Some projection types supported by Petrosys 15 and earlier were
8. SelecunoJxisung THAIS TOMY S erriei a EE EE A OEEO lt aaa E E 38 GeogCRS Transformation Configuration Project seessssseeeen menm nnns 40 GeogCRS Transformation Configuration Site ssssssssssssse nme emen nennen nn 41 PTO CO Hr 42 PrOJCRS EGItOr GeodgCRS Compotlellbu usen cene tdv end lara tits D ei Motta eR dora Ted e ena ban euawencueceean 43 ProjCRS Editor GeogCRS Datums ssssssssseee memes nennen nens suse a nen n 44 ProjCRS Editor GeogCRS Ellipsoids eem 45 ProjCRS Editor GeogCRS Prime Meridians sseeen mmm menm menn 46 ProjCRS Editor Projected CR Sorreraren aaa ttal vu bud m dra niu esed on aot I EDI COH tnl 47 PrOICRS EGItOR PPOIGCLIOLDS uscito css on E duru tB ct cop arid evo rrt r Li opdest Dorn HE De amd ad oae RdE 48 REDOING YOU CRS USB cse sax vara hn EE QR NP AE cia God oo idee 50 CRS Information in Scale Bars and Title BIOCKS cccccccecsecenecterentereneeteneeteneeteneetenententatentetentensntensas 50 CRS Information in Gridding Volumetrics and other XML Reports sse nnns 51 Setting CRS In EXISUDG FIG S cc omo EXE ERES NET EU OR CE CE HERR HE needa Dipl dta en M ea vr dae 53 ASSIGNING CRS to gGroup OL FUGS ui ceametadva diadis rar imd ei nei aV rbpu SEED Rage nene iav dU eu ud E REDE 53 Convertino Project COOF dI ates us ost rari IEEE Stade donde ere tuas dme DEB RAN eiue Paw AEA ASET 54 Petrosys Coordinate Reference Systems CRS 2 of 54
9. as continental drift As a result present day locations are frequently specified in a regional CRS such as NAD83 GDA94 or NZGD2000 other than WGS84 Known Problems in CRS Using CRS correctly does not by itself guarantee that your spatial data analyses and maps will be perfect or unique l If you mix data from different CRS in one map or computation then coordinate Petrosys Coordinate Reference Systems CRS 5 of 54 transforms will be used by the software Not only are all transforms an approximation there are usually several types or versions of transform available to convert within a given CRS pair Running the same job after selecting a different transform method will produce different results Projected CRS the process by which coordinates on an ellipsoid are mapped to a flat display all involve some distortion Computations based on the eastings and northings from projected CRS such as areas lengths and volumes are all subject to the errors brought in by this distortion Petrosys Coordinate Reference Systems CRS 6 of 54 CRS Types There are several types of Coordinate reference system catering for different levels of precision and viewing requirements In these definitions the Geoid is the actual physical planet Earth 2D Geographic CRS 3D Geographic CRS Projected CRS Geocentric CRS Engineering CRS Horizontal coordinates are specified in angular units latitude and longitude relative to
10. associated with the correct GeogCRS for the data can be used Petrosys Fault Files A single ProjCRS is recorded which is assumed to apply to all faults in the file Well Data File A single ProjCRS is recorded which provides the GeogCRS and the ProjCRS for all the data in the file DbMap Database The dbMap database records individual CRS against individual data objects so any combination of CRS can be supported Culture and Seismic SDF Files As it is difficult to upgrade these file structures in a backward compatible manner culture and SDF files do not currently record CRS information The project default CRS is applied when these files are included in maps and computations Petrosys Coordinate Reference Systems CRS 28 of 54 Unknown and Undefined CRS in Petrosys Data If a Petrosys file has not been updated to include CRS data as yet then it s CRS content is deemed to be undefined or missing When such a file is used on a map or in a computation the current project default CRS is applied to the data If a file is to be updated to including a CRS reference but you do not know what CRS to assign then you can assign the Petrosys custom GeogCRS or ProjCRS for an Unknown CRS to the file Once this is assigned you know that the file has been looked at and found to be genuinely in doubt as opposed to possibly being of a known CRS but simply not having been touched as yet Files with Unknown assigned as the CRS will have the
11. be consistent and repeatable to within the mathematical correctness of the transformation CRS and The Physical Earth WGS84 Our ability to relate coordinates precisely to physical points on the Earth depends on the correctness of the CRS transformations available relative to the surveying machines that we use to measure the coordinate on the ground At the time of writing the most commonly used surveying machines are based on Global Positioning System or GPS technology and are usually but not always programmed to give readings in the WGS84 coordinate reference system To use a range of different CRS on the same map or in the same interpretation a set of transformations between these must be available In general a transformation from a CRS to WGS84 is usually a prerequisite for current mapping providing a common standard through which transformations for other combinations of CRS can be constructed The WGS84 CRS is designed to precisely locate points in a smooth satellite orbit rather than on the Earth s somewhat irregular surface Operations such as distance and area measurements computed using WGS84 locations for points on the Earth s surface have a degree of error which is based in part on the deviation of the Earth s shape at that point relative to the ideal shape orbited by the satellite In addition the absolute location of physical parts of the Earth relative to the satellite orbit will change over time owing to processes such
12. develop and disseminate best practice to provide a forum for the exchange of experiences and knowledge to influence Regulators and Standards organisations to liaise with industry associations to be the voice of Surveying and Positioning in the Oil and Gas industry The main areas by which the Surveying and Positioning Committee work to achieve these objectives are the EPSG Geodetic Parameter Dataset http www epsg org Geodetic html the OGP Surveying and Positioning Guidance Notes http www epsg org guides index html maintenance of positioning data exchange formats http www epsg org ExchForm html and through association with other organisations EPSG Geodetic Parameters The OGP Surveying and Positioning Committee through its geodesy sub committee maintains and publishes a dataset of parameters for coordinate reference system and coordinate transformation description The EPSG Geodetic Parameter Dataset has been included as reference data in UKOOA and SEG positioning data exchange formats the GeoTIFF interchange format for georeferenced raster imagery the IHS Energy Iris21 PPDM and POSC Epicentre data models The dataset is distributed in an MS Access relational database and SQL script files and may be downloaded here http www epsg org Geodetic html End of quote from web site epsg org Other CRS Sources ESRI the developers of the ARC suite of geographical information systems GIS products have an est
13. intersects the ellipsoid A projection that only touches the ellipsoid will have one line of latitude whereas one that intesects it will have two With a unit scale factor linear distortion in the east west direction will be least along the standard parallel For regional maps the standard parallels are usually within the map area One cartographic convention for Lambert projections is to use standard parallels 1 6 of the way into the map from the southern and northern edges Projection Types Supported in Petrosys The projection type names used in Petrosys software conform to the EPSG database standard More detailed information on specific projection types may be available in topics with headers of the form PROJECTION TYPES Transverse Mercator Mercator 1SP Mercator 2SP Oblique Mercator Hotine Oblique Mercator Cylindrical conformal projection extensively used for small to medium scale maps and the basis of UTM map projections The axis of the cylinder lies in the equatorial plane as opposed to Mercator in which it is along the axis of rotation Cylindrical conformal projection with the axis of the cylinder being the rotational axis of the Earth Cylindrical conformal projection extensively used for regional and navigation maps As for Mercator 1SP but with two standard parallels Cylindrical conformal projection similar to Mercator but with the cylinder axis aligned neither with the Equatorial plane as in a
14. is defined This collection of knowledge may include information such as a geodetic datum a map projection and a range of mathematical transformations To specify a coordinate in a manner that it can be used in conjunction with data from various sources the coordinate reference system within which the coordinate is defined needs to be known How is a CRS Specified CRS are referred to by names or collections of data that vary widely between systems and locations CRS references can be confusingly similar The EP spatial analyst needs to be vigilant for potential mis interpretations of what a given CRS reference means and to encourage the use of precise and industry standard CRS specifications The most widely recognised form of a CRS reference is a common name such as NAD27 or AMG zone 52 A name such as NAD27 can mean different things in different contexts for example it might refer to a geodetic datum or to a 2D or 3D geographic CRS A more specific and unique way of referring to CRS is through the use of EPSG codes The EPSG European Petroleum Survey Group initiated a standardisation of CRS used in the petroleum industry in which each CRS is assigned a unique numeric code These codes and their underlying definitions are published in a database currently maintained by the OGP surveying and positioning committee Petrosys Coordinate Reference Systems CRS 4 of 54 Well known text WKT EPSG codes whilst concise an
15. pair check the transform in the second checkbox column which has a traffic light icon in the header You should only have one transform selected as a default for a given GeogCRS pair to avoid ambiguity in processing results Petrosys Coordinate Reference Systems CRS 41 of 54 ProjCRS Editor File Maintain CRS Projected CRS Editor The projected CRS editor allow you to create new projected CRS based on existing projections and GeogCRS to create new projections based on alternate parameters with existing projection types and if you really need to to define new GeogCRS and the associated components You can not modify existing ProjCRS definitions as it is assumed that these may be referred to by data somewhere in your system and a change in the ProjCRS would impact the validity of that data The projected CRS editor starts off with a selection screen showing existing projected CRS Projected CRS Editor Pampa del Castilla Argentina zone 2 PD 83 3 degree Gauss zone 3 PDOs 3 degree Gauss zone 4 Pointe Maire UTM zone 3235 Porta Santa s UTM zone 2oh 3061 Porto Santo 19595 7 UTM zone ZN POSGAR 34 Argentina 1 POSGAR 34 Argentina 2 POSGAR 34 Argentina 3 POSGAR 34 Argentina 4 POSGAR 34 Argentina 3 POSGAR 34 Argentina B POSGAR 34 Argentina 7 POSGAR 38 Argentina 1 POSGAR 38 Argentina 2 i a Om TAO Of F Aranntina Owner EPSG Mame Porta Santa 1995 UTM zone z alM Geographic CRS Porto S
16. the Type column header so that you can scroll to the part of the list that contains all Lambert projections Each of the established projections is the combination of a projection type with a specific set of parameters which usually tie that projection down to it s use within a particular latitude and longitude range If the projection that you need is not there as yet then use the New button to create an additional projection around one of the supported projection types This is described in the help topic ProjCRS Editor Projections Petrosys Coordinate Reference Systems CRS 47 of 54 ProjCRS Editor Projections Projected CRS Editor Projection New A new projection can be created when the required combination of projection type and parameters does not yet exist This will usually be where a projection type is to be applied in an area where it has not been used before or covering a significantly different extent Creation of a new projection is usually triggered from the projected CRS editor Projected CRS Editor Pampa del Castillo Argentina zone 2 J396 PDOs 3 degree Gauss zone 3 J397 PD 83 d degree Gauss zone 4 eBe3de Pointe Moire UTM zone 325 1 ed42 Porta Santa UTM zone z M dl 3061 Forto Santa 1995 UTM zone 28h ee lal POSGAR 34 Argentina 1 ecli POSGAR 34 Argentina 2 ee lad POSGAR 34 Argentina 3 ec lid POSGAR 34 Argentina 4 g
17. 00 for example the false easting of zone 3 is 3 500 000 An early Australian zone scheme used until the 1980 s used Yards as coordinates and had zone numbers starting with 1 just beyond the Western edge of Australia Petrosys version 15 and earlier allowed the explicit definition of zone numbering schemes This was to allow modelling of schemes such as the above as an alternative to specifying a central meridian References References to the sources of specific projection types are accessible in the metadata field Information Source of the EPSG database tables This information is currently accessible on the EPSG CRS browser accessible through the Tools page of the Petrosys web site http petrosysguru com There are many excellent references on projection types including the following books Petrosys Coordinate Reference Systems CRS 19 of 54 l Cartographic Projection Procedures for the UNIX Environment A User s Manual U S Geological Survey Open File Report 90 284 May 13 1990 2 Geodetic Coordinate Systems in Australia J Manning and J Steed Preview August 1994 3 Map Projections Used by the U S Geological Survey Geological Survey Bulletin 1532 Second Edition 1982 On the Internet there are many good references on projections which are best discovered using an Internet tool such as Google or Wikipedia The USGS http t m gov and Geoscience Australia http www ga gov au are good starting points
18. 1 8 POSGAR 34 Argentina 5 ec lob POSGAR 34 Argentina 5 ecla POSGAR 34 Argentina 7 ee 71 POSGAR 38 Argentina 1 eelfe POSGAR 38 Argentina 2 om 1 72734772 Duuaceus4pgmgs 5x nwntin F EPSG Porto Santa 1995 UTM zone ZN Porto Santo 1335 Bew UTM zone zalM Owner ame Geographic CRS Projection Cw er UTM zone 2435 UTM zone 25M UTM zone 2535 UTM zone 25M UTM zone 2535 UTM zone 27M UTM zone 275 UTM zone 28h UTM zone 2835 UTM zone 28M UTM zone 2335 UTM zone M UTM zone 25 UTM zone 30M 16026 l EPsG 16026 Owner Projection ID Projection Mame Transverse Mercator Remarks 000000N 0150000W 08888 500000 False narthing LIEN Units Metres v Close New Save Save s Delete Projection type Reference latitude Central meridian orale factor False easting Petrosys Coordinate Reference Systems CRS 48 of 54 Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator Transverse Mercator UTM zone 26h Use the New button at the foot of this screen to define a new projection Projected CRS Editor Projection Editor Owner Code 16124 UTM zone 245 Ka New Pro
19. Coordinate Reference Systems Table of Contents Coordinate Reference Systems ovid a bon e UE DE E EN RT POR ERR VEO RA KOC E C ee EU pa b een 1 Coordinate Reference Systems Background ccce ee een eene nnn 3 Coordinate Referente SySEeTmissasrkessatsdaatadu ead YS ween e d RO bia ERR DIE E DU co e e PR RT HAUS 4 What is a Coordinate Reference System sesessssseses sese sese sanus a haha apu ER RENE R ADAG ADA DAHER EH RR aus Edu da SEES 4 PIOW AS a CRS SDeCITIQU uei weeds ut are acta LL M D E LM uM ae hate M MIA M a ede 4 Well KnoWwn texte WKE scie stenosis cisco ee ac vena ta open d LM ILS UM I I DE d Ue 5 CRS TraNSTONMN ATIONS orron oia S 5 CRS ano The Physical Earm WOSS4 i a aea e A ETEENI E Aia EEE MP hoe 5 KDowh ProDIemsJm RS roria rosaa DUX e Lex vedere tuse i son cu deua aes ee Deas Goede oe ee 5 CRS TYDES ETE E ES 7 SO CR s MP 8 Compohents OF Ar GCOO0 CR osi erst seh aI EEE ines aide enemies cee aed eae bases 8 GCOGCRS TEFODSTOFTDQUODS ers a a es Ee eae ida ee a ea eee cee ae econ ees 8 GCODGR gt Datu M TI P m 9 There may be several GeogCRS for one datum esessssssssssseses esee sena ahhh sas u sa asas sah au du dua aua an 9 Cotmmmonty used aalus arna ase EA UP Loa cu ru bu te cet ciis cM ere ee ao 9 GeogGRs ENDS OF SPNErO uasa ssesu qas dast aa deri deb
20. D53 ES GRS 1980 g GRS 1380 Authalic sphere g Helmet 1906 g ril k Hough 1350 J ry Indonesian National spheroid e Mee International 1924 g O24 Krassowsky 1940 e 4 1 7025 NWL 3D Jm 3 T 32 OSUGGF J 7033 OSL81 4 Own Ej 2 foe Plessis 1817 T054 Pz 3 EPS gt F028 Struve 1660 AC 7070 ar in Dat Owner EPSG Ellipsoid id T z2 Rem IP Ellipsoid name International 1924 semi Major axis a 5378388 semi Minor axis E 6356911 94612 a Flattening f mre D 003357003 Inverse flattening 1 297 Eccentricity fe 0 0801881880 081331830 second eccentricity e 0 082268890 Dat 1 Adopted by IUGG 1924 in Madrid Based on Hayford 1909 1910 Remark figures l E Info source Data source lE m CI eee ud i Close Bew Save Save As Delete Please remember to insert appropriate remarks as to why you created the ellipsoid entry Petrosys Coordinate Reference Systems CRS 45 of 54 ProjCRS Editor GeogCRS Prime Meridians Projected CRS Editor Geographic CRS New Datum New PrimeMeridian New A new prime meridian needs to be registered in the rare cases where a GeogCRS datum is based on some location other than the Greenwich meridian Many such cases are likely to have already been defined in the EPSG system so please ensure that you have the correct information at hand before taking this step Remember to check for minor round off errors that may be insignificant
21. G database will be available every 3 6 months or so Petrosys are currently developing scripts to help your systems administer audit the changes between your existing and any more current version of the EPSG database and to synchronise your EPSG definitions with the latest ones Please contact Petrosys support for more information Petrosys Coordinate Reference Systems CRS 32 of 54 Coordinate Reference Systems Tools Petrosys Coordinate Reference Systems CRS 33 of 54 Choosing an Existing CRS WDF Edit General Mapping Mapsheet Edit Projection Details You will be required to choose a CRS when l you are setting the projection information for a map sheet 2 you are providing default CRS information for data sources that don t include it 3 a coordinate transform function has been selected Petrosys has different selectors for Projected and Geographic CRS selection The Projected CRS selector is a superset of the Geographic CRS selector as you have to select a GeogCRS before you can pick one of the embedded ProjCRS Coordinate Reference system Projected CRS GDA94 MGA zone 55 Geographic CRS GDA84 Projection Transverse Mercator Spheroid GAS 1980 W Projected CRS Selector mx File Help Geographic CRS Projected CRS Fiji 1986 MGA zone 51 Fort Marigot MGA zone sz MGA zone 34 GDMe2e000 i MA zone 54 GGRSB7 MGA zone 55 GRAB MGA zone S5 Gan 1970 MGA zone of Garoua MGA zone S8 Grand Cayman 1959 MaW Lamb
22. PSG CRS Browser Petrosys maintains a web browseable version of the EPSG database in the Tools section of it s web site http petrosysguru com This allows you to query the EPSG database to find projected and geographic CRS that are commonly used in different parts of the World Projected Coordinate Reference systems 1 More detailed information can be made available in a pop up window by clicking on the data in these columns Projcks Code 20256 20356 2317 28356 2102 2101 210 2066 0200 314 27120 2067 ProjCRS Harme Aliases AG066 Ano zone 56 ADDS AMG zone 56 PSADS56 ICH Regional DDAS4 WGA zone 56 Lake Maracaibo Grid Lake Maracaibo Grid Mi Lake Maracaibo Grid hi5 Mount Dillon Tobago Grid hdount Dillon Tobago Trinidad 1905 Trinidad Grd Trinidad 1905 Trinidad Trinidad 1905 Trinidad Grid ficla Maparima 1972 UT hi zone 20h Maparima 1372 UT hl 20h Maparima 1355 UT hi zone 20h Maparima 1955 LIT hd 20h Projection 1 Projection Type 1 1 Area of Use 1 Remarks Hare GecgcRs Australian hap Transverse Mercator 46066 Australia 150 to 156 Grid zone 56 deg E Australian hap Transverse Mercator 40084 Australia 150 to 156 Grid zone 56 deg E ICM Regional Lambert Conic FS4056 Wenezuela onshore Conformal 25F hiap Grid of Transverse Mercator nDAS4 Australia 150 to 156 Australia zone 56 deg E Ilaracalbo Grid Lambert Con
23. RS implementation in a project uncheck the option to overwrite CRS in the data source This will preserve any previously converted or computed CRS information and only modify those files not yet assigned a CRS In general you should use both the backup files option and do a trial run The assign CRS option assigns a new CRS without taking into account any existing knowledge of the CRS in a file and does not need the project default CRS Petrosys Coordinate Reference Systems CRS 53 of 54 Converting Project Coordinates The option File Maintain CRS Convert project coordinates will also assign a single CRS to a group of files however it will convert the coordinates in the files from any existing or default CRS to do so Control is similar to that of the Assign option but you are also reminded to review the project default CRS as this will be applied as the input CRS for any files in which the CRS has not yet been defined acco rdinate context conversion File selection method use file listing users volker dev nmsumm ship test dump test file list tet Project default projected CRs Default M amp Dz7 s UTM zone 13M Output projected CRS NADAS UTM zone 15M Overwrite existing project default projected CRS MN Backup files MN Overwrite existing backup Backup mode use mirrared file Backup root directory Resample grid ta new projected CRS Resize grid Trial run Actual run f e S
24. a mix of a projection type and specific parameters and were replaced with individual projections rather than projection types in Petrosys 16 RSO in metres was replaced with the EPSG projection Timbalai RSO metres epsg 29873 RSO in feet was replaced with the EPSG projection Timbalai RSO feet epsg 29872 NTF was replaced with the EPSG projection NTF Lambert zone 1 epsg 27571 Petrosys Coordinate Reference Systems CRS 30 of 54 Submitting CRS Proposals All coordinate reference systems used in the EP industry should ideally be uniquely identified by codes with associated definitions in the EPSG database If you come across projections or projected or geographic CRS that you are confident of but which aren t yet defined then you can ask to have them included in future EPSG releases At the time of writing the best way of initiating such a request is to go to the EPSG web site http www epsg org and to follow the links EPSG Geodetic Parameter Dataset then CHANGE REQUEST which is at the bottom of that page This change request might also be accessible through the OGP website at http info ogp org uk geodesy Comms Comment asp Petrosys Coordinate Reference Systems CRS 31 of 54 Updating your CRS Definitions Your CRS definitions will initially be based on those shipped with a given version of Petrosys These will be installed in your local configuration area ps local It is anticipated that an updated version of the EPS
25. a specific reference ellipsoid which is the assumed approximation of the geoid Elevations are not included as part of the coordinate Horizontal coordinates are specified in angular units latitude and longitude relative to a specific reference ellipsoid which is the assumed approximation of the geoid and elevations are specified as the vertical offset from the reference ellipsoid Horizontal coordinates are specified in units such as northing and eastings in meters measured on some planar surface which approximates the Earth s surface All coordinates are expressed in a 3D rectangular framework with the origin at a presumed centre of mass of the Earth Coordinates are expressed in some local coordinate system selected for convenience in precise relative positioning rather than for their relation to distant locations or measurements made at some other time Petrosys currently only uses 2D geographic and projected CRS Any reference in this documentation to a Geographic CRS or GeogCRS is a reference to a 2D geographic CRS To correctly specify a location as a latitude and longitude there must be a reference to the associated geographic CRS somewhere To correctly draw a point on a map there must be a reference to a projected CRS Petrosys Coordinate Reference Systems CRS 7 of 54 GeogCRS A Geographic CRS or GeogCRS for short allows locations to be defined on a spherical coordinate system taking into acco
26. ablished system of CRS codes that closely match those of EPSG Petrosys 16 exchanges CRS knowledge with ESRI products quite reliably Oracle use a CRS coding system in their Oracle Spatial product Contact Petrosys support for current information Petrosys welcomes the opportunity to exchange information about standardisation in CRS use Petrosys Coordinate Reference Systems CRS 23 of 54 between applications and across regions XML Encoding GML The standard GML or Geographic Markup Language encoding of coordinate reference data has not been adopted by Petrosys at this stage as it does not fully define the content of the EPSG standards XML encoding of coordinate reference data is discussed in the help topic Reporting Your CRS Use Petrosys Coordinate Reference Systems CRS 24 of 54 Petrosys CRS Stores Petrosys stores CRS definitions using a relational data model that closely follows that used in the EPSG OGP database The data are physically stored in either Oracle or SQLite database instances A hierarchy of storage locations is used to allow corporate site and project based CRS definitions to co exist Oracle and SQLite Versions of CRS Definitions Sites using both the non Oracle pseis menu system and the Oracle based pseis db will be running a mix of the Petrosys mapping program which gets it s CRS information from an SQLite database and dbMap which gets it s CRS information from the Petrosys dbMap databas
27. anta 1995 Mew Projection UTM zone 28M Close New Save Save As Delete Use the New button in the screen footer to trigger creation of a new ProjCRS as described in ProjCRS Editor Projected CRS Petrosys Coordinate Reference Systems CRS 42 of 54 ProjCRS Editor GeogCRS Component Projected CRS Editor Geographic CRS New A new GeogCRS can only be created at the site level as a GeogCRS has strong implications for data management You can start creation of a GeogCRS by using the New button against the GeogCRS selector in the ProjCRS editor Projected CRS Editor a Pampa del Castilla Argentina zone 2 J396 PDOs d degree Gauss zone 3 Jag PDOs d degree Gauss zone 4 eoede Pointe Maire LITM zone 325 F zg4z Forto Santo UTM zone Za8M E 3061 Forto Santo 1335 UTM zone 8M T 22181 POSGAR 94 Argentina 1 ei 22182 POSGAR 94 Argentina 2 ei 22172 POSGAR 98 Argentina 2 re Sedes mise Duabus y Aranantina 2 EPSG Porta Santa 1385 UTM zone 28M Parto Santo 1335 Bew Mare Geographic CRS Projection Wa Geographic CRS Editor Bix l 4636 Petrels 1972 4252 Pointe Noire b 4615 Porto Santo i 4663 Porto Santo 1995 d 4583 PRS3 2 d 4248 PSADSB d 4133 Puerta Rico d 4754 Pulkava 1942 2 4179 Pulkovo 1942158 1 41472 Diilkoun d 242 272 FJ wher EPSG EPSG code 4663 Mame Forto Santo 1995 Datur Forto sant
28. ch as ProjCRS MAP PROJECTED CRS NAME gt gt epsg lt lt MAP PROJECTED CRS CODE gt gt in the footer text part of a custom scale bar using Edit Scale bar in the mapping then picking that custom scale bar as part of the Mapsheet Layout or by using Display Scale bar you will get a scale bar which includes ProjCRS information 1 100000 0 1 2 3 4 z mm m 9 KILOMETRES g 2 3 4 2 inm o au M 4 MILES ProjC RS GDA94 MGA zone 54 epsg 28354 Petrosys Coordinate Reference Systems CRS 50 of 54 Text substitution has been used in the Petrosys example title block PetrosysTitleBlock16 cgm which is shipped in the ps misc area to show CRS information in the title block footer Example title block with substitution of CRS parameters WFW 7 er ES PS COMICI firms krtssMeces seme 111141 Jameraprize O ACACA CIE CD Ae Cw cmne 84 mpeg 28384 EAJ sig G F S 1333 zLI erac Mapsui22 GLENELG CF L F Mapfie clenelg bass sp cEm CRS Information in Gridding Volumetrics and other XML Reports The projected CRS is extremely important in gridding and volumetrics as the spatial information is based on scaled values that have been computed through a projection and based on a given datum In a Petrosys gridding workflow task list XML or workflow log XML file all CRS information involved in the workflow is included at appr
29. d CRS for easting northing coordinates in files and on maps Petrosys Coordinate Reference Systems CRS 11 of 54 GeogCRS Prime Meridian The prime meridian associated with a GeogCRS is the place representing the origin of the longitudes ie the vertical line around one half of the Earth at which the longitude in that GeogCRS is O For most GeogCRS used in Petroleum EP the prime meridian is Greenwich based on which the survey markers at Greenwich in the United Kingdom have a longitude of O GeogCRS that have prime meridians other than Greenwich include the ATF Paris which has a prime meridian located in Paris and for which the units are in grads rather than degrees You cannot create a GeogCRS with a non zero prime meridian in Petrosys and data supplied with prime meridians other than Greenwich may not be processed correctly Petrosys Coordinate Reference Systems CRS 12 of 54 GeogCRS Transformations Transformations relate GeogCRS to one another In Petrosys a GeogCRS transformation or transform is essentially the same as a datum transformation One transform converts between one GeogCRS and another using one specific type of mathematical process and a specific set of parameters By chaining a sequence of transforms Petrosys can undertake transforms between pairs of GeogCRS for which no direct transform exists A transform between a GeogCRS and WGS84 is usually required for such chaining of transforms to be
30. d for almost all work in a given region the only reason for using variants of this would typically be if you are accessing historical data based on an earlier GeogCRS for example NAD27 in a region based on NAD83 or AGD660 in a region based on GDA94 Having picked a geographic CRS your first preference for a projected CRS should be from amongst those already defined within that geographic CRS at your site These will automatically be presented in the projected CRS selection tool Creation of new CRS s should be approached with some caution in particular in well established exploration areas where good mapping standards have been developed The selection process for a projected CRS within a geographic CRS is e Is your work an extension of existing work in a region and is there general satisfaction with the mapping in that region In that case pick a projected CRS currently used in that region or a CRS that reflects some lateral extension of the region within the same projection type for example a UTM projCRS in an adjacent zone e What projection type eg transverse Mercator Lambert is most suitable Stay with the projection types most commonly used in your region at that scale Different projection types are commonly used for small and medium scale as opposed to regional scale maps If the main aim of your projected CRS selection is for map displays the numeric characteristics of the projection type are not that important If
31. d unique are dependent on their definition in the EPSG database and on a knowledge of that database As this cannot be guaranteed a common form of CRS specification is to include as much information as is known about the CRS with easily recognised key word labelling as a well known text or WKT string The WKT specification for the GDA94 MGA zone 55 CRS for example can look like PROJCS GDA94 MGA zone 55 GEOGCS GDA94 DATUM Geocentric Datum of Australia 1994 SPHEROID GRS1980 6378137 298 257222101 AUTHORITY EPSG 7019 AUTHORITY EPSG 6283 PRIMEM Greenwich 0 UNIT degree 0 0174532925199433 AUTHORITY EPSG 4283 PROJECTION Transverse Mercator AUTHORITY EPSG 17355 PARAMETER latitude of origin 0 PARAMETER central meridian 147 PARAMETER scale factor 0 9996 PARAMETER false easting 500000 PARAMETER false northing 10000000 UNIT metre 1 AUTHORITY EPSG 28355 CRS Transformations If we have two coordinates that are measured in the same coordinate reference system then we know that operations comparing these coordinates such as distance bearing and area computations will be consistent and repeatable within that measurement system If we have two coordinate measured in different coordinate reference systems and we have a unique coordinate transformation between these coordinate reference systems then operations comparing coordinates measured across the two systems will
32. dJUnderineq CRS 2i idv ean chee Po ou otieii2 boe Reed I MIRI 21 Coordinate Reference Systems Data Management eee eene nne 22 International CRS Standard Sissi sieved ese anse tains oU tutto ewnss es vines uet alata e heut Lee Lure ut 23 gie E ANG GIC HMM T IT errr eter rrr 23 OME ECRI SOUT COS cialis ett ad et piro vm oisi cuba V pia Me c OE A T Me D MS 23 AMEENCOOING Cii ECHTE 24 POUOSVS CRS STOO Carissimi a nee nt ne uuu ee E dst CAN AU nude EL ne 25 Oracle and SQLite Versions Of CRS Definitions caes seen enhn nnn anna nhan 25 Project ana Site CRS DefIiltIoll Sos ucetus eeivtuia da tbc eran ti tema e Ere res eu e Rr LIA ee Rec TRU uL T RIAM eae 25 Gra Shift Filles Tor Datum Gonvefslorns xx ree ee eee pel Vet i adiu pcxd tea EEE S 25 Project Delal CRS EE 25 SOLILG Datapase NOTOS e EEE AE A TAERE ADETE Venda E E E AT 25 PeroSyS EPSG CRS Bi OWS GM anecitzexc i a aara e e ea vetu ru Ds e I ea 27 Petrosys Data Store CRS References sesssssssesssssesen senem nennen nessuna sas ses resa nenas 28 PETOSVS GHG FCG pM DM 28 Ghid Sampled Data GIP FIOS faces esce hat vende ecu sae once AT AARTE eae E up UU tees 28 PetrosvsGODtoUr FCS sos pcd En n PD PPP IPM IM LI MEA MM MED pM I RUE 28 Petrosvs PoOlVOQOITEIIBS manani suut uetus aa veterum EUS A E ASE cM Pei c t dd aS 28 PETOS FAUCET OS M n cuales 28 WH DEA FUG tapas panto ited
33. data stores so that they have an explicit knowledge of CRS embedded in them See Petrosys Data Store CRS References for a description of files that can support storage of CRS information Files created by Petrosys 16 and later will contain CRS information if the file supports this Files created by earlier versions of Petrosys can be updated to include a CRS using individual header editors such as the polygon header editor or they can be upgraded using one of the two bulk editing options File Maintain CRS Assign CRS to files and File Maintain CRS Convert project coordinates Assigning CRS to a Group of Files The recommended way of setting CRS to a collection of files from the same spatial context is to use the option File Maintain CRS Assign CRS to files v FERE CRS to Petrosys data source File selection method se file listing usersvolker dev nmsumm ship test dump test tile list tet Projected CRS MADS UTM zone 15M Overwrite existing project default projected CRS MN Overwrite CRS in data source MN Backup files M Overwrite existing backup Backup mode use mirrared file Backup root directory Trial run Actual run pick a file list containing the names af the files you want ta convert This will convert all relevant files in a given directory or files listed in a text file to having a single projected CRS or the associated GeogCRS assigned to them If you are uncertain of the status of C
34. e Contact Petrosys support for further information on how this may affect your CRS data management Project and Site CRS Definitions CRS shipped with Petrosys are stored as part of your Petrosys implementation at the site level in the ps local area Once installed they are not automatically updated or modified by future Petrosys releases Many aspects of CRS such as custom ProjCRS definitions may be created at either the site or the project level Use the project level if you are trying out some projection for short term use Use the site level for work that needs to be shared You can not define GeogCRS at the project level The definition of a geographic CRS has important data management implications Any information such as a grid contour or polygon file which is created with locations referenced to a geographic CRS becomes dependent on the knowledge of that CRS It is not possible to reliably transfer the spatial content of such a data set to another project unless the geographic CRS is also accessible to that project For this reason Petrosys does not allow the creation of geographic CRS s at the project level Any geographic CRS that you create becomes available at the site level so that any data created which refers to it can be reliably exchanged If you are in any doubt as to the need to create a new geographic CRS please consult your company geomatics expert or refer to Petrosys support Grid Shift Files for Datum Conve
35. eferences All file upgrades discussed in this section have been in a backward compatible manner between Petrosys 16 and 15 If you update one of the files in 15 the CRS information added by 16 will however usually be lost CRS references in Petrosys data files are recorded as well known text This means that they can be matched to other systems in the future should the EPSG code definitions no longer be available Petrosys Grid Files The single ProjCRS is recorded as being applied to the whole grid All information in the grid is assumed to be in a ProjCRS As Petrosys supports the Plate Carree projection which simply assumes that latitudes and longitudes are eastings and northings it is possible to use a grid in which the units are decimal degrees Grid Sampled Data GIP Files A single ProjCRS is recorded that applies to all the data in the file Petrosys Contour Files A single ProjCRS or GeogCRS is recorded depending on whether the contours are in projected or geographic coordinates It is not possible to mix projected and geographic coordinates in one contour file Petrosys Polygon Files A single ProjCRS is recorded which is assumed to apply to all polygons in the file Note that a polygon file may contain a mix of projected and geographic coordinate polygons or even have only geographic coordinate polygons in it If there are no geographic coordinates in a polygon file and there is no intent to ever add any then any ProjCRS
36. effective GeogCRS Transform Methods Petrosys supports the GeogCRS transformation methods shown here Molodensky 3 parameter transform The least precise fastest and most widely used form Bursa A 6 parameter transform HARN Grid based transform for North America High Accuracy Reference Network NADCON Grid based transform for North America North American Datum Conversion NTv2 Grid based transform for Canada National Transformation Version 2 Grid based transforms use collections of control points at which very precise offsets grid shifts are specified and between which a specific form of interpolation is applied These control point sets are provided in reference files some of which are supplied by Petrosys in the ps_misc area A grid based transform will only work over the area for which grid shifts are specified Errors will be reported for data lying outside of the area of interest of a selected grid based transform Selecting the Most Appropriate Transform No GeogCRS transform other than a no transform transform is perfect Different compromises are selected to get fast computation with reasonable numeric results in different areas For popular GeogCRS pairs such as NAD27 to NAD83 there may be several GeogCRS transformations available You can select a specific GeogCRS transform for a pair of GeogCRS s from those available using the File Preferences Project Geographic CRS Transformat
37. efine a new Bursa Wolff transformation for example the following screen is presented Petrosys Coordinate Reference Systems CRS 37 of 54 Transformation Editor CRS file Site ps rels petrosys local ps site crs sdb Source geographic CRS Target geographic CRS Transformation method Bursa shifts to W sB4 metres Rotation to Woso4 arc seconds dis FR dy rv orale correction to WOso4 ppm Selecting Existing Transforms Existing GeogCRS transformations can be browsed and selected using the GeogCRS Transformation Editor EPSG transformations can not be edited The parameters associated with the specific transformation are listed in the information panel of the dialogue as you scroll through the various transforms Petrosys Coordinate Reference Systems CRS 38 of 54 For a Molodensky method transform for example only dx dy and dz shifts are provided Geographic CRS Transformation Editor Name Camacupa ta WGS a4 4 Camacupa ta WGS a4 3 Camacupa ta WGS a4 E Camacupa ta WGS a4 7 Camacupa ta WGS a4 a Camacupa to Ws a4 3 Camp Area Astro to Was 84 1 Campo Inchauspe ta POSGAR 34 1 Campo Inchauspe to WGS a4 1 Campo Inchauspe to WGS a4 iz Cape Canaveral to Was 84 1 Cape to Hartebeesthaek34 1 Cape to Was 84 1 Cape to Was 84 2 Carthage to Was 84 1 Cahana tn MZ ma rns Owher EPsG Source geographic CRs Campo Inchauspe Target geographic CRS POSGAR 34 T
38. eral hundred projections have been published each preserving different geometrical characteristics The type of work and area to be mapped will dictate the choice of the projection Some characteristics normally considered in choosing a map projection are Area A projection can be designed to be equal area so that area is preserved Shape Many of the most common projections in use today are conformal This implies that every small feature of the map is shown correctly Relative angles at each point are correct and the local scale in every direction around one point is constant For example on a conformal map meridians intersect parallels at right angles Scale No map shows scale correctly throughout the entire map but there are usually one or more lines on the map for which the scale remains true Direction Conformal maps give the relative local direction correctly at every point Azimuthal maps have the directions of all the points on the map correct with respect to the centre Construction The construction method will be based on either the cone or a cylinder or a plane Conic and Cylindrical Projection Types The most common projections used are either Conic or Cylindrical Conic projections are based on the concept of folding the map into a cone A cone is placed over the globe with the surface of the cone touching the earth along some particular parallel of latitude The meridians of longitude and the parallels are projected onto
39. ert nactiw g Grand Comoros of Lambert Greek TM Ch 141 Greek Athens SSS Granada 1954 i LL a L EPSG code 20355 Name ODAS4 MGA zone 55 Projection type Transverse Mercator Longitude at natural origin 147 000 147 00 ODE Latitude at natural origin 0 000 00 OO OON Scale factor at natural origin 0 999600 False easting 500000 False northing 10000000 OK Cancel The ProjCRS for a given GeogCRS are presented in the left panel as you scroll through different GeogCRS Details of the currently highlighted ProjCRS are presented in the lower part of the panel If you don t see a GeogCRS or ProjCRS which you think has been defined refer to your systems administrator and then to Petrosys support The list of available CRS may have been reduced to meet the perceived needs of your site or there may be a more recent version of the EPSG database available that has not yet been installed at your site Current EPSG CRS can be queried using the EPSG CRS browser in the Tools section of the Petrosys web site http petrosysguru com Petrosys Coordinate Reference Systems CRS 34 of 54 Defining a New CRS Some of the situations in which you may need to define a new CRS are l You want to create a map sheet with projection parameters not available in a currently available CRS This is particularly common with Lambert and Mercator projections 2 You need feet or US feet units in an area normally measured in metres
40. i from the centre of the ellipsoid to the widest and narrowest axis of the ellipsoid respectively They are typically around 6 378Km or 20 925 000 feet 2 The semi major axis can be specified as a length as above with an inverse flattening value which typically has a value of around 297 The inverse flattening 1 f semi major axis a and semi minor axis b are related by the formula 1 f 2 1 b a In the EPSG database individual ellipsoids are specified in one or the other form depending on what form the original definition of the ellipsoid was given This is to avoid round off errors Historical Ellipsoids Some commonly used ellipsoids are Clarke 1866 Clarke 1880 ANS Australian National Spheroid WGS84 Everest 1830 International 1924 There are many variants of ellipsoids referred to by historical data The EPSG database for example lists at least five variants of the Clarke 1880 ellipsoid When working with historical data it s important to match the ellipsoid parameters by their numeric value rather than just relying on the ellipsoid name Petrosys spheroid dat file Prior to Petrosys 16 ellipsoids or spheroids were defined by Petrosys in a file called Spheroid dat This file might exist either in the ps misc ps local or the local project directory The ellipsoid definitions from spheroid dat were used in the creation of the projections used in map sheets which in turn were used to specify projecte
41. ic Lake Wenezuela Maracaibo Grid coordinates are 200000 200000 at Maracaibo Cathedral 10deg 38min Conformal 15 P area 34 5 T 8ser M 7Tideg 36min 20 224560 Yt Lake dahim Used for Lake triangulation coordinate listing Maracaibo Grid Lambert Conic Lake Venezuela Maracaibo Grid coordinates are D 0 at hlaracaibo Cathedral 10deg 38min 34 6 78sec M ihi Conformal 15 P area Tideg 36min 20 2243ec Wt Lake datum Used by Creole GO and Sun Projection Details Coordinate Operation 18261 Frojection name Frojection type Method code Latitude of natural origin Longitude of natural origin Scale factor at natural origin False easting False northing Remarks Metadata piano at maracaibo Cathedral 10deg s amp amin 4sec Ve Lake datum Used bu Varco J F Mozilla Maracaibo Gnd Maracaibo Grid Lambert Conic Conformal 1 SP 9301 ge nidad Grid cade 30200 used by some oca Trinidad 10 1 F1 3620224 1 200000 147315026 Grid coordinates are 200000 200000 at Maracaibo Cathedral Information source Various oil company sources Date source EP SG Revision 20000507 The EPSG browser is kept up to date with new EPSG releases so it can be used to identify CRS that may not have been installed on your local Petrosys system as yet Petrosys Coordinate Reference Systems CRS 27 of 54 Petrosys Data Store CRS References Petrosys data file structures are being progressively upgraded to incorporate CRS r
42. in your context Creation of a prime meridian is triggered using the New button against the Prime Meridian field of the datum editor iw Projected CRS Editor a aetna CRS Editor mx iy Datum Editor mx H maren d C e 4 COwrier Code S Athens 2 Bern 3 4 Bogota Brussels g 4 Ferro i H B SEDE Greenwich g Jakarta A Lisbon A D Madrid 2 Oslo EX 4 Y Faris 4 Rome own Fy stockholm EPS a Ma seul E caa EPSG BE Prime meridian code 6901 Rem Ell Prime meridian name Greenwich 00 Pri Prime meridian from Greenwich PO Remark Info source C Re Data source Re van oem Nee save Save As Delete I Please remember to insert appropriate remarks as to why you created the prime meridian entry Petrosys Coordinate Reference Systems CRS 46 of 54 ProjCRS Editor Projected CRS File Maintain CRS Projected CRS Editor New A new projected CRS needs to be created when the combination of a projection type projection parameters and geographic CRS are not yet defined amongst the CRS on your system Use the New button in the Projected CRS editor to create a new ProjCRS W Projected CRS Editor wr ene MADEJ Texas Contra MUS g 3133 MARSS Texas Centric A bers zyual Area i dJ32 MOOG Texas Centre Lambert oTormal gt DE ale NADO z Texas Penh r7 E HADES Texas Penh tlla Dr 32138 Nabe
43. ions in the mapping application The transforms accessible in this option can be controlled on a site basis using the File Maintain CRS CRS Configuration option Use the detailed information shown in the transformation selector to judge which is the most appropriate transformation in your environment Warning Using the wrong GeogCRS transform will result in offset errors in maps and data based on the GeogCRS s involved Petrosys Coordinate Reference Systems CRS 13 of 54 ProjCRS A projected CRS or ProjCRS is a two dimensional reference system measured in a plane that been juxtaposed on the Earth in some manner often by wrapping into a conical or cylindrical shape A ProjCRS is built on a GeogCRS every projected CRS is associated with an underlying geographic CRS Selecting a defined ProjCRS therefore implicitly also selects a GeogCRS ProjCRS are inherently useful as it is easy to draw a map by scaling ProjCRS coordinates to fit to a rectangular reference system on a flat page In the terminology of Petrosys 15 and earlier a projected CRS is the application of a specific map projection to a specific datum Selecting an Appropriate Projected CRS The first step in selecting a projected CRS is to ensure that you know the geographic CRS within which it is defined and that you have the appropriate GeogCRS transforms picked to make this work with any other data that you are using In general the same geographic CRS will be use
44. jection CRs file Site ps rels petrosys local ps site crs sdb Projection Name Mie Projection type fransverse Mercator Remarks Reference latitude Central meridian e a e e a e e a a a e Scale factor False easting False nothing Units False nothing Units Metres Close Neu Save Save As Delete Select the appropriate projection type then enter the parameters appropriate to that projection type The dialogue for projection parameters will vary in accordance with the requirements of the selected projection type See the help on PROJCRS PROJECTION TYPE for more information on specific parameters Petrosys Coordinate Reference Systems CRS 49 of 54 Reporting Your CRS Use It s important to report the coordinate reference systems used in your maps reports and data sets CRS Information in Scale Bars and Title Blocks You can include the projected and geographic CRS names and codes in custom scale bars and title blocks using the CGM clear text substitution strings MAP PROJECTED CRS CODE EPSG code for projected CRS MAP PROJECTED CRS NAME Name of projected CRS MAP GEOGRAPHIC CRS CODE EPSG code for geographic CRS MAP GEOGRAPHIC CRS NAME Name of geographic CRS MAP CRS WKT Full well known text string for all parameters in the projected CRS This is a long string which may not work correctly in title blocks Including a string su
45. le in multiple projects to ensure a reliable means of exchanging spatial data between projects For this reason Petrosys does not allow the creation of geographic CRSs at the project level Any custom geographic CRS that you create is stored at the site level If you are in any doubt as to the need to create a new geographic CRS please consult your company geomatics expert or refer to Petrosys support Petrosys Coordinate Reference Systems CRS 36 of 54 GeogCRS Transformation Editor File Maintain CRS Geographic CRS Transformation Editor GeogCRS transformations provide a conversion from one GeogCRS to another typically being some form of datum conversion You can define new GeogCRS transformations and browse the definitions of existing ones using the Geographic CRS transformation editor You can not change the definition of an existing EPSG transform as this would compromise the integrity of your data relative to other sites Defining New Transforms New GeogCRS transformations can be defined in the Geographic CRS Transformation Editor Transformations added in this way will be assigned a large code number to differentiate them from the EPSG standard transformations A limited range of transformation methods is supported Each method has a unique set of parameters such as dx dy which are presented in the dialogue when the transformation method is picked See the help on GeogCRS Transformations for more information To d
46. ment Most petroleum exploration work was not datum aware until the 1980 s At that time most countries had national standard datums which had been established for many decades and these datums were the basis of locations acquired until the early 1990 s With the advent of GPS and WGS84 new datums that were more precisely related to WGS84 were adopted by many countries The order of magnitude of the difference in locations specified in older and current datums is typically around 100 metres but can be as small as a few metres or as large as half a kilometre This table shows some common older and current datums for selected regions with some comments on their establishment and relationship to one another The table is provided solely to make the reader familiar with some commonly used datums and should not be used to assign datums to locations for which the datum is unknown Petrosys Coordinate Reference Systems CRS 9 of 54 Region Older Current Remarks Datum Preferred Datum 2007 North America NAD27 NAD83 NAD27 is still widely used in the USA as a lot of legal information as well as a mass of government archival data is specified in NAD27 The preferred transformations between NAD27 and NAD83 are significantly different between Canada and the USA Europe ED50 ETRS89 Australia AGD66 GDA94 As at 2007 most companies are getting close to completing transformation of all data to GDA94
47. mmon to have many different transformations applied in different circumstances depending on accuracy relative to location computational speed restrictions and requirements for elevation to be included By itself a GeogCRS can be assigned to a spatial data set to complete the knowledge of what that spatial data means even if no associated transformations exist To use such spatial data in a situation where data from multiple GeogCRS exist appropriate transformations must be available A transformation to WGS84 is usually a prerequisite to general use of information that includes a range of GeogCRS s Petrosys Coordinate Reference Systems CRS 8 of 54 GeogCRS Datum The datum in a geographic CRS defines how the ellipsoid is positioned relative to the actual Earth and may include further detailed deviations from the ellipsoid in specific regions There may be several GeogCRS for one datum It s tempting to think of a GeogCRS as being equivalent to a datum for example to think of the GeogCRS GDA94 as being the Australian GDA94 datum In many cases you can make the simplifying assumption that the 2D GeogCRS with the name of a datum is the datum as used in Petrosys However you should always bear in mind that there may be different GeogCRS that refer to the same datum for various reasons such as e 3D GeogCRS which include elevation information are more precise than 2D ones Gravity data points for example are often defi
48. n is applied The default and unknown CRS can be set using the File Select option in the main menu and the File Preferences CRS option in the mapping menu Petrosys Coordinate Reference Systems CRS 21 of 54 Coordinate Reference Systems Data Management Petrosys Coordinate Reference Systems CRS 22 of 54 International CRS Standards Support for international standards for CRS encoding and parameters is critical for the long term development of spatial knowledge about our EP resources EPSG and OGP The CRS used in Petrosys are based on the publications of the OGP Oil and Gas Producers Surveying and Positiong Committee and the EPSG European Petroleum Survey Group The status of this group as at April 2007 is summarised by this extract from the web site http epsg org Start of quote from web site epsg org The OGP Surveying and Positioning Committee was formed in 2005 by the absorbtion into OGP of the now defunct European Petroleum Survey Group EPSG which itself had been formed in 1986 The Surveying and Positioning Committee comprises specialists from OGP member companies working in the areas of surveying geodesy cartography and coordinate data management Meetings are held twice yearly A short brochure about the OGP Surveying amp Positioning Committee can be downloaded from http www epsg org AboutSnP pdf Objectives The OGP Surveying and Positioning Committee has the following objectives to
49. nce Systems CRS 15 of 54 ProjCRS Projection The projection component of a ProjCRS is the specific mathematical formula used to translate the latitudes and longitudes of the point to the ProjCRS values which are typically eastings and northings A projection comprises a projection type and the parameters applied to that projection type in the specific instance Examples of projections UTM zone 11N A UTM projection type applied with the parameters for zone 11 which has a central meridian of 117W in the northern hemisphere MGA zone 54 A UTM projection type applied with the parameters for use in the southern hemisphere zone 54 based on the standards for the Map grid of Australia or MGA SPCS83 Utah Central zone A Lambert projection defined by government agencies for use in the state US Survey feet of Utah USA and having linear units of US survey feet Petrosys Coordinate Reference Systems CRS 16 of 54 ProjCRS Projection Type A projection type is a general mathematical formula for transforming spherical to cartesian coordinates eg latitudes and longitudes to eastings and northings Projection Characteristics Since any projection cannot be done without distortion you must choose the geometrical characteristic which is to be shown accurately at the expense of others or instead select a compromise of several characteristics There are many ways in which this can be done and as a result sev
50. ned on a 3D GeogCRS If you apply 2D GeogCRS transformations to such data you will lose significant information e There may be minor variants of an ellipsoid that have been used historically with the same datum resulting in multiple GeogCRS e Organisations have been known to use different GeogCRS s to identify uncertainty in the allocation of datums where the datum had not been recorded with the original data Commonly used datums The ITRF International Terrestrial Reference Frame is the name used for the international standard datum The physical representation of the ITRF varies in time owing to changes in surveying technology and the planet itself To specify an ITRF datum the specific version such as ITRF92 must be given The ITRF is rarely used in real EP data but documentation frequently defines other datums with reference to it WGS84 is the most commonly used datum in the 1990 s and 2000 s WGS84 has been defined to work effectively with satellite navigation systems build around the Global Positioning System GPS WGS84 is an approximation of ITRF version of 1992 ITRF92 In future new satellite navigation systems may prompt the definition of alternate datums to WGS84 The European Galileo satellite radio system will be compatible with the GPS and in a 2003 document was described as requiring a positional shift of only a few centimetres relative to WGS84 In 2007 there was also a Russian alternative to GPS under develop
51. o 1995 Bew Supersedes 1936 system CRS code 4515 Remark Instituto Geografico e Cadastral Lisbon http dwew 1geo pt G Info source ii Data source EPSG Close Mew Save Save As Delete Petrosys Coordinate Reference Systems CRS 43 of 54 ProjCRS Editor GeogCRS Datums Projected CRS Editor Geographic CRS New Datum New In the event that you come across a datum not yet recorded in EPSG the GeogCRS editor allows you to create a new datum at the site level Projected CRS Editor Geographic CRS Editor fv Datum Editor Philippine Reference system 1992 Phoenix Islands 1355 Pico de la Mieves Pitcairn 1357 Point 38 Pointe Geologie Perroud 1350 Porto santo 1335 EBS Porto Santo 1995 Posiciones Gendesicas Argentinas 1334 Posiciones Gendesicas Argentinas 1338 Potsdam Datum a3 Provisional south American Datum 1355 Puerto Rico Pulkovo 1342 EPSG Datum code BES Datum name Porto Santo 1335 Ellipsoid International 1924 Frime meridian Greenwich Datum scope Realisation epoch 1995 Classical and GPS observations Supersedes 1936 adjustment datum code gt Remark 6615 For Selvagens see Selvagem Grande datum code 6616 Instituto Geografico e Cadastral Lisbon http wew igeo pt jo Info Source Ellipsai Clarke 1666 International 1924 International 1924 International 1924 Clarke 1880 RGS International 1824 International 1824 International 1824 GRS
52. od Hadcon NOT SUPPORTED Parameters Grid files ps rels petrosys l6 misc datums canus 1as NSW 3z 2 ps rels petrosys 16 misc datums conus laos MTF Transform version NGS Usa Conus NTF Parisi Scope Accuracy at 67 confidence level is 0 15m onshore 5m nearshore and WFAN undetermined farther offshore E j OK Cancel one el el el el el el el el el el el lel el el el el el el el rz Start by selecting the source GeogCRS in the left pane The target GeogCRS for which transforms have been defined are then automatically displayed in the central pane To make a GeogCRS accessible at a site check the GeogCRS in the Source Geographic CRS column Use the right mouse button to quickly check or uncheck all GeogCRS Then highlight the target GeogCRS for which transforms are to be configured Available transforms are then tabulated in the right pane Detailed information about the transforms is listed in the lower pane as you scroll from transform to transform See GeogCRS Transformations for more information on transformation types All transforms that are defined in your site CRS database are visible in this dialogue To allow a transform to be accessed by all users at your site check the box in the left hand column with the eye icon in the header This simply means that a user will see the transform and can chose it if they want To make a transform the default transform for the currently highlighted GeogCRS
53. of an azimuthal equidistant projection used in the Pacific If you require support for a projection type not currently available in Petrosys please let Petrosys support know preferably with some enthusiastic supporting reasons for the use of the specific projection type UTM and Other Zones Many cartographic conventions split the World into vertical zones along bands of longitude to standardise the way in which central meridians are assigned for small to medium scale mapping across wide regions The most commonly used zone scheme at present is that associated with UTM Universal Transverse Mercator projections In this the World is split into 6 degree wide zones each with it s own central meridian starting with zone 1 from 180W to 174W and with a central meridian at 177W and ending with zone 60 which spans 174E to 180E The false Easting for each zone is repeated as being 500 000 UTM projection names will usually include the zone number for example UTM Zone 17N is a UTM projection for zone 17 ie a central meridian of 81W in the Northern hemisphere In South America a zoning scheme based on Gauss Kruger projections is used This uses 3 degree wide zones which work in NS elongated countries like Chile and Argentina The projection Argentina zone 5 for example is based on a zone from 58 5W to 61 5W with a central meridian of 60W This scheme has unique false eastings created by adding the zone number multiplied by 1 000 000 to 500 0
54. opriate levels of the XML and should be taken into account when this XML is published Most of the XML tags involving the CRS will have the upper case string CRS as part of their name For example in a grid workflow log XML information about the projected CRS applied in the output grid is available both as the CRS name and as the well known text the quotes have been expanded from amp quot to and the text has been wrapped for clarity in this example lt OutputProjectedCRS gt PROJCS AGD84 AMG zone 48 GEOGCS AGD84 DATUM Australian Geodetic Datum 1984 SPHEROID Australian National Spheroid 6378160 298 25 AUTHORITY EPSG 7003 AUTHORITY EPSG 6203 I PRIMEM Greenwich 0 UNIT degree 0 0174532925199433 AUTHORITY EPSG 4203 l PROJECTION Transverse Mercator AUTHORITY EPSG 17448 la PARAMETER latitude of origin 0 PARAMETER central meridian 105 PARAMETER scale factor 0 9996 Petrosys Coordinate Reference Systems CRS 51 of 54 PARAMETER false easting 500000 PARAMETER false northing 10000000 UNIT metre 1 AUTHORITY EPSG 20348 lt OutputProjectedCRS gt lt OutputProjectedCRSName gt AGD84 AMG zone 48 lt OutputProjectedCRSName gt Petrosys Coordinate Reference Systems CRS 52 of 54 Setting CRS in Existing Files File Maintain CRS Assign CRS to files File Maintain CRS Convert project coordinates It is important to upgrade existing
55. or vice versa 3 You want to create a map sheet for a geographic CRS with a non standard datum 4 You have been provided with data that is in a projection or datum not supported by a current CRS 5 You want to define an alternate geographic CRS for a given datum to differentiate information based on your confidence in the datum assignment Before defining a new CRS you should critically review your choices 1 Is the CRS required by you defined in the EPSG standard but not visible at your site as it has been blocked by the administrator 2 Could your requirement for a non standard CRS be based on some error in your data source such as inadequate precision or a typing error in some values 3 Could your requirement be based on a nomenclature issue such as an alternate name for a supported datum 4 Is there an existing convention related to selection of projection parameters that you can follow to make it more likely that your proposed CRS will match those generated elsewhere For example using central meridians that conform to those of the UTM zones using Lambert standard parallels offset by 1 6 of the way into a standard map sheet and using a false northing of 10 000 000 metres in the southern hemisphere New CRS have to be defined in a hierarchical manner If your datum and projection are all unsupported then you have to define the new datum and any associated transforms first then the geographic CRS then the projected CRS wi
56. ransformation method Molodensky shifts to wasg metres dis 148 000000000 dy 136 000000000 dz 30 000000000 e e e e e e e e e e e e Close Mew Save cave As Delete For a Bursa Wolff transform there is a more complex collection of parameters Geog raphic CRS Transformation Editor Owner Name Camacupa ta WGS a4 4 Camacupa ta WGS a4 3 Camacupa to WGS a4 E Camacupa ta Ws a4 7 Camacupa ta WGS B4 rB Camacupa ta Was a4 8 Camp Area Astra to WaS B4 1 Campo Inchauspe ta POSGAR 34 1 Campo Inchauspe to WGS a4 1 Campo Inchauspe to WGS a4 iz Cape Canaveral to Was 84 1 Cape to Hartebeesthaek34 1 Cape to Was 84 1 Cape to Was 84 i2 Carthage to Was 84 1 Cahana tne MZ ma rns Owher EPsG Source geographic CRS Camacupa 56 666 eee 566 666 6 Target geographic CRS Was 84 Transformation method Bursa shifts to W sB4 metres Rotation ta WsB4 arc seconds d 41 057000000 FA O 000000000 dy 374 564000000 rv O 000000000 orale correction dz 226 287000000 re 0594000000 ta W sa4 ppm 0 219000 Close Neu Save Save As Delete Petrosys Coordinate Reference Systems CRS 39 of 54 GeogCRS Transformation Configuration Project Mapping File Preferences Project geographic crs transformations Within a project you can select alternate GeogCRS transforms to the default ones for a site by using the File Preferences P
57. roject geographic crs transformations option from dbMap or the mapping application CRS configuration project geographic CRS transformations Source Geographic CRS Target Geographic CRS X Version Monte Mario Rome NAD ta NADSS 1 NGS LUsa Conus Madcon Montserrat 1356 NADE3 CSRS NAD27 ta NADAS 2 NGS Usa AK Moorea 87 WGS 84 NAD27 to NAD83 4 GC Can NT2 Mount Dillon Moznet NAD2 MaDe Michigan Nabe Frey NADe2riCG T MADEJ NADEJICSRS NADE J HARNY MOG Paris Transform code gt 1241 MES7T4 Noumea Name NADS to NADSS 1 MGN Petrosys key ONAD2Z NGO 1948 Petrosys name NAD 1927 MADCON CONUS Method gt Hadcon MGO 1348 Oslo Parameters Grid files ps rels petrosys 16 misc datums conus 18s NOT SUPPORTED ps rels petrosys 16 misc datums canus los NSWC 92 2 Transform version NGS Usa Conus MTF Scope Accuracy at 67 confidence level is 0 15m onshore 5m nearshore and RITE Pariet Undetermined farther offshore p J OK Cancel Pick the source GeogCRS for which a transform is to be selected in the left pane The GeogCRS for which transforms from this are available will be listed in the middle pane Pick the target GeogCRS from these which results in all available transforms for the pair appearing in the right pane Details about each transform can be viewed in the lower pane as you scroll through the transforms See GeogCRS Transformations for more information on transformation
58. rsions Some transformations such as Harn and NTV2 transforms between North American NAD27 and NAD83 GeogCRS s are based on reference files These reference files are sought along the PS _PATH ie in your project initially then in the the Petrosys local area and finally in the Petrosys software misc area Project Default CRS The project default CRS which is assigned to any files for which no CRS has ever been considered and the project unknown CRS which his assigned to data for which someone has stated that the CRS is specifically not known as opposed being unavailable are stored on a per project basis in the file panels pnd as at Petrosys 16 0 In Petrosys 16 1 this information will be moved into a more general site information data store as the panels pnd file is frequently replaced for operational reasons SQLite Database Notes As at Petrosys 16 Petrosys uses SQLite version 3 Third party utility software is available to manipulate SOLite databases The most commonly Petrosys Coordinate Reference Systems CRS 25 of 54 used is sglite As successive versions of sglite have been incompatible it is necessary to use the sglite3 utility with Petrosys SQLite databases The file name dot suffix for an SQLite database is sdb On some Windows installations this results in Windows Explorer wrongly identifying SQLite databases as being of type AppFix Petrosys Coordinate Reference Systems CRS 26 of 54 Petrosys E
59. rue v aA SEP io tfbnt a Lp EP CO eco 11 PUISCONIGAI EDS OII Si ED 11 PetrosyssSDDerolg Qat TIIO cadets att epe iets eel he do Bie ee dee ere 11 GeogChsS Pre Meri IIo siia ter euler tina ble f etd vie ved a Rad da Flex ale ea pe ed an Re 12 GE0GECRS TransTormalblofib s cda rum xor POTERE weet ks gU PIN ERE DO IR te on EREUURFE bea NAE 13 GOOUGCRS Transrornt MetlTOGS ten qose eco at Rates va sa tatu ion E sd ifl eru Dh roba fd a ira p EE OE 13 Selecting the Most Appropriate Transform eeesssesseee sese sese sena sunu suena susus usua u tasas usadas esuada ada 13 PEO CRS ierutuitrt svi rennet xoa E Ve aad ctu bte d puer Ya asso Face Mou A oe ana lehsD desde RUOTE MA 14 Selecurig am Appropriate Projected GRS scoduo operosa andre vites av ita ras ntium AR EA REUS 14 Pro CRS uas eje EEME H 16 PIoIC RS Projector IVDC aranaren aa ur Sacra Cano p Rar hu a an E v a a dro aa d MEER RN 17 PFOJECUON Chara teris UC rm 17 CONIC and Cylindrical Projection TYpeS sssssssseesnnnnnsenssnsnnnrnsrnrnnnrnnrrnrrnrnnernrrnrrnrnnrrnrnnrnnenrerrenne 17 Projecto nP arane tOr FL ETE E sites EEEE EE E EE AAE OETA 17 Projection Types Supported Im PetrosyS niaaa venu cents A oy Fi a aAa OE EAEE 1a Ido oT PRU PP RrES 18 UTM andgoOttler ZOMCS caer aay teased Cie ua sis MI Ti CI LL dM M ME d RM M de 19 alc acr f M 19 Unknown an
60. that eastings to 500 000 units on either side of the central merdian will have positive values The line of latitude used as the base line for computation of north coordinates For many projections the Equator latitude 0 is used Notable exceptions include Nigera where a 4 degree reference latitude is commonly used and some Gauss Kruger CRS for South America which have a 90S reference latitude For stereographic projections a 90 degree reference latitude implies a polar stereographic projection 0 an Equatorial stereographic projection and any another value implies an oblique stereographic projection The northing coordinate assigned at the reference latitude In the northern hemisphere this often takes the value of 0 In the southern hemisphere 10 000 000 is often used ensuring that all northings in the south remain positive The scale factor usually at the central meridian is the linear distortion introduced by a projection at the reference space UTM projections use a scale factor of 0 9996 along the central meridian as the linear distortion in the projection increases computed distances as you get away from the central meridian The factor of 0 9996 ensures that data about one third and two thirds of the way across the zone has the correct linear scale whilst data on the outer parts of the zone is extended and data on the inner parts is compressed The lines of latitude where the folded map sheet of a projection touches or
61. the cone The cone is cut along a meridian unrolled and laid flat Cylindrical projections are similar to conic projections except that a cylinder is wrapped around the globe so that its surface touches the equator Cylindrical projections are used primarily for world maps or for maps where the greatest extent is from north to south Conic maps are commonly used for the opposite namely those maps where the greatest extent is from east to west and for larger geographical areas The most common cylindrical projections are UTM and Transverse Mercator The more common conic projections are the Lambert Albers and equi distant Conic Projection Parameters Each projection has a number of parameters some of which are set by the projection and others which must be defined The types of parameters that may need to be defined for a particular projection include Central Meridian The line of longitude associated with the centre of the projection This should typically be within a few degrees of lying on the map itself and should be within the map for large regional maps There are many conventions for assigning central meridians such as the zone schemes Petrosys Coordinate Reference Systems CRS 17 of 54 False Easting Reference Latitude False Northing Scale Factor Standard Parallels described below The easting coordinate assigned at the central meridian This often takes on a large 6 digit value such as 500 000 which means
62. ther geographic CRS then a transformation to WGS84 will usually be the minimum required New GeogCRS based on an existing Datum This is most likely to be required as part of the support of a new datum following on from the definition of that datum as described above You can create a new geographic CRS based on an existing datum by clicking the New button at the foot of the geographic CRS editor Main File Maintain CRS GeographicCRS Editor or dbMap Admin CRS Projected CRS Editor Geographic CRS Editor Cy ner Code Abidjan 1987 Y 4188 Accra FJ 4201 Adindan 4705 Afgooye Y 4206 Agadez Y 4202 AGDBB Y 4203 AGD84 Y 4204 Ain el Abd Y 4131 Albanian 1387 i 4183 American Samoa 1382 Y 4203 Amersfoort Y 4138 Ammassalik 1358 Y 4600 Anguilla 1957 Y 4601 Antigua 1343 Y 4206 Aratu l Ana fre TOC LE Owner EPSG e LESS geographic CRS EE FE BETTE BETTE R AR e EPS code 4143 CRS file Mame Abidja D atum Abidja Name Supers Datum Remark Remark Info source Info source Data source EPSG Close New cose Data source Cancel Note that you have to have defined the datum and any associated transforms before you can create the geographic CRS through which the datum can be used The definition of a geographic CRS has important data management implications It is generally required to be consistently availab
63. thin this New ProjCRS based on an existing GeogCRS This is the most common scenario in which an unsupported projection is to be added for an existing geographic CRS You can create a new projected CRS based on an existing geographic CRS by clicking the New button against the Projection field in Mapping Mapsheet Edit Projection details Main File Maintain CRS ProjectedCRS Editor or dbMap Admin CRS Projected CRS Editor Projection UTM zone z M Neu This brings up the projection editor described in the section ProjCRS Editor Projections New Datum A new datum is likely to be required if you are working with historical data or in an region not recently explored by EPSG member companies Remember that a datum is a general standard for a collection of positioning information that conforms to one geodetic reference and is typically defined by a source such as a national mapping organisation and some reference date which is typically a year There may be many transformations for a given datum to other geographic CRS including WGS84 Do not define a new datum if you have alternate datum transformation parameters for an existing datum To define a new datum use the New button next to the datum selector field Petrosys Coordinate Reference Systems CRS 35 of 54 After defining a new datum you need to define the transformations from this datum to other datums If you are going to mix data from this datum with data from o
64. transverse Mercator nor with the axis of rotation as in a standard Mercator Variant of Mercator used in Alaska and Malaysia Lambert Conic Conformal 1SP Conic conformal projection The scale is true along the single standard parallel Lambert Conic Conformal 2SP Conic conformal projection extensively used for onshore regional mapping Parallels are unequally spaced arcs of concentric Petrosys Coordinate Reference Systems CRS 18 of 54 circles more closely spaced near the centre of the map Meridians are equally spaced radii of the same circles intersecting the parallels at right angles The scale is true along either of the two standard parallels Equidistant Conic General conic projection which is neither conformal nor equal area but which is equidistant One or two standard parallels may be used American Polyconic Conic projection used in Brazil Oblique Stereographic Azimuthal conformal projection used for mapping around the poles and other special circumstances By setting the reference latitude to O this becomes an Equatorial stereographic projection and by setting it to 90N or 90S it becomes a polar stereographic projection Albers Equal Area Conic equal area projection often used for regional maps in the USA One or two standard parallels may be used Van Der Grinten Projection used to draw whole of the Earth maps in a circle which is neither equal area nor conformal Guam Projection A simplified form
65. types Check the required transform to be used and exit You should only select one transform for any given GeogCRS pair Petrosys Coordinate Reference Systems CRS 40 of 54 GeogCRS Transformation Configuration Site File Maintain CRS Configuration Site admnistrators can use the File Maintain CRS Configuration option to restrict the GeogCRS transformations that are visible at a site and to direct users to the preferred transformations Restricting the GeogCRS visible to those that are to be used at your site is an effective way of simplifying the user interface and avoiding possible errors from chosing the wrong CRS It merely affects the visibility of the information not of the ability to store or work with data that uses the CRS The user interface is similar to that of the project based transformation configuration however it includes an additional column to select the visibility of transformations at a site 5 configuration Source Geographic CRs Target Geographic CRS V X Version Montserrat 1358 Moorea 87 Mount Dillon hdoznet I MaDe to MADS 1 Mas Usa Conus MADBS CSRS MAD2 ta NADES 2 MiG s Usa AK Was Gd MAD2 ta WADE d GaC Can NTZ MAD27 ta MADE 5 sGG Can GC NTZ MaDe Michigan MaDe Frey NADeriCG T MADEJ NADB3r C SRS NA DB83rHARN MOG Paris NEA 74 Noumea Transform code 1241 MGN Name NAD27 to NAD53 t1 Fetrosys ke gt NAD27 MGIC Wet Jd rans gt NAD 1927 MADCON CONUS NGO 1348 Oslo Meth
66. unfortunately web sites get reorganised frequently and there are copyright implications on quoting web links so we won t try to provide more explicit links Petrosys Coordinate Reference Systems CRS 20 of 54 Unknown and Undefined CRS Our ability to have CRS associated with all spatial data is still evolving There is a lot of historical data which has no CRS defined and some present data stores and applications don t carry over CRS information as yet In addition some existing CRS assignments may be unreliable Petrosys supports two distinct concepts in dealing with incomplete CRS knowledge A spatial data set has an undefined or a missing CRS if the source of the data or the data store was not CRS aware ie if there was simply no way of providing the CRS or if a CRS aware store had never had an explicit CRS entry made in it ie you haven t had a chance to look at it as yet A spatial data set has an unknown CRS if there is some way of storing a CRS with the data and that store has been specifically set to unknown This is used in situations where you have made a concious decision that you can not determine the CRS for some data and have recorded that decision against the data When an undefined CRS is encountered in the Petrosys application a ProjCRS noted as the project default CRS is applied as the assumed CRS for the data When an unknown CRS is encountered in the Petrosys application a ProjCRS noted as the CRS for unknow
67. unt the shape of the Earth The Earth does not have a physical mid point that provides an absolute and unique origin for coordinate systems It deviates not only from being a sphere but also from being a well formed ellipsoid In addition the mathematics applied in the definition of the coordinate system can use different units origins and methods for taking into account elevations A GeogCRS encapsulates the information required to uniquely define how a consistent suite of survey data is related to our view of the Earth Components of a GeoqCRS A GeogCRS includes the following information e The ellipsoid or spheroid being a version of an ellipsoidal shape to the Earth which is not positioned at any specific place relative to it e The datum being a specific way of positioning the ellipsoid relative to the Earth and which can also define local variants from the ellipsoidal shape e Units of measure which in are usually degrees for latitude and longitude Other angular units not normally used in geomatics include radians and grads A circle has 360 degrees 2xpi radians or 400 grads e Additional metadata about the CRS such as the standards organizations responsible data sources and remarks GeogCRS Transformations Geographic CRS transformations can be defined that allow location definitions in one GeogCRS to be converted to being consistent with another GeogCRS Such transformations are necessarily approximations It is co
68. your projected CRS is to be used for volumetrics and area calculations then you should try to understand the implications of linear and area distortions that some projections involve e Having decided on a projection type the specific location of that projection on the Earth needs to be specified The parameters for this vary with type of projection but will usually require your consideration of whether you are in the northern or southern hemisphere and what longitude is to be the central meridian or reference longitude for your projection e Your choice of a central meridian should take into account any established mapping standards in your region The UTM system breaks the world down into zones each of which has a central meridian that is 177 degrees plus a multiple of 6 degrees Lambert projections for specific states are often centered on some historic location in the state If you see a central meridian with a large number of decimal places try converting it to a degrees minutes seconds format to see if it was actually a round number or minutes or seconds e Your choice of hemisphere is usually clear however when working across the Equator Petrosys Coordinate Reference Systems CRS 14 of 54 you may have the choice of using northern or southern hemisphere conventions in the other hemisphere Some early southern hemisphere projections are also based on using the south pole as a reference latitude Petrosys Coordinate Refere

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