The spatial reference system is defined with a single definition string, which is commonly an EPSG definition, or a Well Known Text (WKT) string. Some specific custom definitions may also be used.

EPSG codes

Most EPSG definitions corresponding to standard projection cartographic systems are supported.

The syntax is “EPSG:CODE” to define a cartographic system with its EPSG code (for instance “EPSG:32651”).

Non metric systems are not used (eg. geographic systems).

Well Known Text (WKT)

OpenGIS Well Known Text format for coordinate systems can be provided in as is.

Other definitions

The following syntax may be used to define local East-North-Up (ENU) systems: “ENU:LAT,LON” (for instance “ENU:41.57231,2.26157”).