This is an old revision of the document!
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.
Support of EPSG
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.
More information about CRS and Map Projections: see CRS (Wikipedia) and Map projection (wikipedia)
To set the Dataset CRS of a dataset in Orbit GIS, see general
MapCanvas CRS
Custom CRS Definitions
The EPSG dataset does not and cannot record all possible geodetic parameters in use around the world. OrbitGIS accepts new CRS definitions from OGC (Open Geospatial Consortium) well-known-text (WKT) files. Those WKT files should have .prj filename extension
How to add a 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.
- After starting OrbitGIS the new CRS systems can be found by selecting “Undefined Area” from the CRS area (By Country) list.