gml:VerticalDatumPropertyType is property type for association roles to a vertical datum, either referencing or containing the definition of that datum.
<complexType name="VerticalDatumPropertyType"><annotation><documentation>gml:VerticalDatumPropertyType is property type for association roles to a vertical datum, either referencing or containing the definition of that datum.</documentation></annotation><sequence minOccurs="0"><element ref="gml:VerticalDatum"/></sequence><attributeGroup ref="gml:AssociationAttributeGroup"/></complexType>