This document defines a profile of the Geography Markup Language (GML) version 3.1.1 for encoding definitions of grid coverage (including image) Coordinate Reference Systems (CRSs) plus related coordinate Transformations. This document also specifies some Universal Resource Names (URNs) for definitions in the "ogc" URN namespace, in addition to those specified in [OGC 05-010]. Additional specific URNs are defined for definitions of the datums, coordinate systems, and coordinate system axes which are often used in definitions of grid and image CRSs.
This profile can be used without a GML Application Schema, and such use is assumed in this document. However, a GML Application Schema that uses this profile could be specified. For example, an Application Schema could specify "GridCRS" as a better name for a DerivedCRS that uses a CartesianCS. Or an Application Schema could allow or require more information to be encoded for an OperationParameter (such as specified in Subclause 14.3.2 and wctsOperationParameter.xsd of OGC Discussion Paper [OGC 05-013]).