Type describing the abstract superclass for water objects. As subclass of _CityObject, a _WaterObject inherits all attributes and relations, in particular an id, names, external references, and generalization relations. Type describing Water Bodies, e.g., lakes, rivers. As subclass of _CityObject, a WaterBody inherits all attributes and relations, in particular an id, names, external references, and generalization relations. Class of a Water Body. The values of this type are defined in the XML file WaterBodyClassType.xml, according to the dictionary concept of GML3. Function of a Water Body. The values of this type are defined in the XML file WaterBodyFunctionType.xml, according to the dictionary concept of GML3. Actual usage of a water body. The values of this type are defined in the XML file WaterBodyUsageType.xml, according to the dictionary concept of GML3. Denotes the relation of a WaterBody to its boundary surfaces, which are of type _WaterBoundarySurface. The BoundedByWaterSurfacePropertyType element must either carry a reference to a _WaterBoundarySurface object or contain a _WaterBoundarySurface object inline, but neither both nor none. A WaterBoundarySurface is a thematic object which classifies surfaces bounding a water body. Type for the specification of the level of a water surface. The optional attribute waterLevel of a WaterSurface can be used to describe the water level, for which the given 3D surface geometry was acquired. This is especially important, when the water body is influenced by the tide. The values of this type are defined in the XML file WaterLevelType.xml, according to the dictionary concept of GML3. Type describing the surface of a water body, which separates the water from the air. As subclass of _CityObject, a WaterSurface inherits all attributes and relations, in particular an id, names, external references, and generalization relations. Type describing the ground surface of a water body, i.e. the boundary to the digital terrain model. As subclass of _CityObject, a WaterGroundSurface inherits all attributes and relations, in particular an id, names, external references, and generalization relations. Type describing the closure surface between water bodys. As subclass of _CityObject, a WaterClosureSurface inherits all attributes and relations, in particular an id, names, external references, and generalization relations.