The basic feature model is given by the gml:AbstractFeatureType.The content model for gml:AbstractFeatureType adds two specific properties suitable for geographic features to the content model defined in gml:AbstractGMLType. The value of the gml:boundedBy property describes an envelope that encloses the entire feature instance, and is primarily useful for supporting rapid searching for features that occur in a particular location. The value of the gml:location property describes the extent, position or relative location of the feature.
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.
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<complexType name="AbstractFeatureType" abstract="true"><annotation><documentation>The basic feature model is given by the gml:AbstractFeatureType. The content model for gml:AbstractFeatureType adds two specific properties suitable for geographic features to the content model defined in gml:AbstractGMLType. The value of the gml:boundedBy property describes an envelope that encloses the entire feature instance, and is primarily useful for supporting rapid searching for features that occur in a particular location. The value of the gml:location property describes the extent, position or relative location of the feature.</documentation></annotation><complexContent><extension base="gml:AbstractGMLType"><sequence><element ref="gml:boundedBy" minOccurs="0"/><element ref="gml:location" minOccurs="0"/></sequence></extension></complexContent></complexType>