<xs:complexType name="SurfaceDataPropertyType">
	<xs:annotation>
		<xs:documentation>Denotes the relation of an Appearance to its surface data. The SurfaceDataPropertyType element must either
			carry a reference to a _SurfaceData object or contain a _SurfaceData object inline, but neither both nor
			none.</xs:documentation>
	</xs:annotation>
	<xs:sequence minOccurs="0">
		<xs:element ref="_SurfaceData" minOccurs="0"/>
	</xs:sequence>
	<xs:attributeGroup ref="gml:AssociationAttributeGroup"/>
</xs:complexType>