gml:CompundCRS is a coordinate reference system describing the position of points through two or more independent coordinate reference systems. It is associated with a non-repeating sequence of two or more instances of SingleCRS.
Database handle for the object. It is of XML type ID, so is constrained to beunique in the XML document within which it occurs. An external identifier for the object inthe form of a URI may be constructed using standard XML and XPointer methods. This is doneby concatenating the URI for the document, a fragment separator, and the value of the idattribute.
Source
<element name="CompoundCRS" type="gml:CompoundCRSType" substitutionGroup="gml:AbstractCRS"><annotation><documentation>gml:CompundCRS is a coordinate reference system describing the position of points through two or more independent coordinate reference systems. It is associated with a non-repeating sequence of two or more instances of SingleCRS.</documentation></annotation></element>