A polyhedral surface is a surface composed of polygon patches connected along their common boundary curves. This differs from the surface type only in the restriction on the types of surface patches acceptable.polygonPatches encapsulates the polygon patches of the polyhedral surface.
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.
<element name="PolyhedralSurface" type="gml:SurfaceType" substitutionGroup="gml:Surface"><annotation><documentation>A polyhedral surface is a surface composed of polygon patches connected along their common boundary curves. This differs from the surface type only in the restriction on the types of surface patches acceptable. polygonPatches encapsulates the polygon patches of the polyhedral surface.</documentation></annotation></element>