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--- technologies:geodata_concepts:crs:crs_orbit [2012/02/26 15:24]
jeroen.vermeulen@orbitgis.com [Custom CRS Definitions]
+++ — (current)
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-===== Coordinate Reference Systems in Orbit ======
-This page describes only the use and application of Coordinate Reference Systems in Orbit. \\
-For clear and short overview of the concepts of coordinate systems, datum and projections, see [[crs_theory|]].
-===== Supported CRS =====
-The CRS is a coordinate-based local, regional or global system used to locate geographical entities and can be selected by Country or by datum.
-{{:technologies:concepts:wgs84.png?nolink|}}
-===== Dataset CRS =====
-A coordinate reference system (CRS) or spatial reference system (SRS) is a coordinate-based local, regional or global system used to locate geographical entities. A coordinate reference system defines a specific map projection, as well as transformations between different spatial reference systems. \\
-Coordinate reference systems can be referred to using a SRID integer, including EPSG codes defined by the International Association of Oil and Gas Producers.
-There are two ways to set the CRS of a dataset in Orbit :
-  * [[orbitgis:datasets:general:index|]]
-  * [[orbitgis:datasetlist:dataset:context_menu|]]
-The dataset CRS is saved in the Orbit Resource Descriptor file :
-  * [[technologies:geodata_concepts:ord|]]
-===== MapCanvas CRS ======
-Set the CRS of the MapCanavs using statusbar :
-  * [[orbitgis:mapcanvas:statusbar|]]
-The MapCanvas CRS can be saved in the workspace file :
-  * [[orbitgis:workspace:file:file|]]
-===== Custom CRS Definitions =====
-The EPSG dataset does not and cannot record all possible geodetic parameters in use around the world. Orbit GIS supports custom created CRS definitions if they are structured as described by the Open Geospatial Consortium. [[http://www.opengeospatial.org/docs/01-009.pdf | well-known-text (WKT)]] files. Those WKT files should have the .prj filename extension.
-==== How to add custom CRS definition ====
-  - Create a plain ASCII text file with the extension .prj // and insert the projection parameters as a WKT (well known text) definition on a single line
-  - The prj-file  should be placed in the "<installdir>\program\system\crs" directory
-  - The name of the file should be a numeric code, like "1031370.prj" for example. \\ The numeric code should be larger than 1000000 (one million) to avoid overlap with existing EPSG codes. An optional description can be added to the filename if an underscore character follows the numeric code, like "1031370_Belge 1972 - Belgian Lambert 72.prj" for example.
-  - After starting OrbitGIS the new CRS systems can be found by selecting "Undefined Area" from the CRS area (By Country) list.

Last modified:: 2012/02/26 15:24