gml:AbstractGeneralDerivedCRS is a coordinate reference system that is defined by its coordinate conversion from another coordinate reference system. This abstract complex type shall not be used, extended, or restricted, in a GML Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document.
The attribute gml:id supports provision of a handle for the XML element representing a GML Object. Its use is mandatory for all GML objects. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs.
Source
<element name="AbstractGeneralDerivedCRS" type="gml:AbstractGeneralDerivedCRSType" abstract="true" substitutionGroup="gml:AbstractSingleCRS"><annotation><documentation>gml:AbstractGeneralDerivedCRS is a coordinate reference system that is defined by its coordinate conversion from another coordinate reference system. This abstract complex type shall not be used, extended, or restricted, in a GML Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document.</documentation></annotation></element>