13.1.7 AbstractDatum

A gml:AbstractDatum specifies the relationship of a coordinate system to the earth, thus creating a coordinate reference system. A datum uses a parameter or set of parameters that determine the location of the origin of the coordinate reference system. Each datum subtype may be associated with only specific types of coordinate systems. 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.

Table 13.1.7-1 Associations

Association	Notes
From: AbstractDatum. To: AbstractDatumType Generalization