information about the reference system
identifier and codespace for reference systeme.g. EPSG::4326
Condition: At least one of referenceSystemIdentifier or crs is required
full description of the coordinate reference system to which a coordinate set is referenced
Condition: At least one of referenceSystemIdentifier or crs is required
epoch at which a coordinate set to a dynamic CRS is valid
Condition: Reqired if the CRS is dynamic, otherwise should not be given
type of reference system identifiede.g. geographic2D
defines type of reference system used