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, read crs_theory.

• Supported CRS
  • EPSG
  • Local entities
  • Geoids or Vertical Coordinate systems
• Dataset CRS
• MapCanvas CRS
• Custom CRS Definition
  • How to add custom CRS definition

Orbit has the objective to support all coordinate system as they are described in the EPSG database by the OGP
(International Association of Oil and Gas Producers).

Additionally the following coordinate systems are supported as described by the local services bot for XY as for Z

Belgium, described by NGI.

• epsg31370

Great Britain and Republic of Ireland, described by the Ordnance Survey :

• epsg27700
• epsg29901
• epsg29903

The Netherlands

• RDnap

If required please contact the Orbit support to embed your local defined coordinate system.

Since Oribt 10.3 vertical coordinate systems are supported in Orbit.
An intelligent engine can be used be used to add mathematical Geoid descriptions or vertical grid corrections.
Contact the Orbit support (support at orbitgis dot com) for more information.

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 :

• general
• context_menu

The dataset CRS is saved in the Orbit Resource Descriptor file :

• ord

Set the CRS of the MapCanavs using statusbar :

• statusbar

The MapCanvas CRS can be saved in the workspace file :

• ogw

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 well)known-text as described by the Open Geospatial Consortium :

• International documentation : Well-known-text (WKT).
• Practical documentation for use in Orbit : prj

1. 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
2. The prj-file should be placed in the “<installdir>\program\system\crs” directory
3. 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.
4. After starting OrbitGIS the new CRS systems can be found by selecting “Undefined Area” from the CRS area (By Country) list.