The TopoSurface type and element represent a homogeneous topological expression, a set of directed faces, which if realised are isomorphic to a geometric surface primitive. The intended use of TopoSurface is to appear within a surface feature instance to express the structural and possibly geometric relationships of this surface to other features via the shared face definitions.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods. This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="TopoSurfaceType"><annotation><documentation>The TopoSurface type and element represent a homogeneous topological expression, a set of directed faces, which if realised are isomorphic to a geometric surface primitive. The intended use of TopoSurface is to appear within a surface feature instance to express the structural and possibly geometric relationships of this surface to other features via the shared face definitions.</documentation></annotation><complexContent><extension base="gml:AbstractTopologyType"><sequence><element ref="gml:directedFace" maxOccurs="unbounded"/></sequence></extension></complexContent></complexType>