CityGML is an OGC Standard. Copyright (c) 2012 Open Geospatial Consortium. To obtain additional rights of use, visit http://www.opengeospatial.org/legal/ . Type describing the "root" element of any city model file. It is a collection whose members are restricted to be features of a city model. All features are included as cityObjectMember. Type describing the abstract superclass of most CityGML features. Its purpose is to provide a creation and a termination date as well as a reference to corresponding objects in other information systems. A generalization relation may be used to relate features, which represent the same real-world object in different Levels-of-Detail, i.e. a feature and its generalized counterpart(s). The direction of this relation is from the feature to the corresponding generalized feature. Type describing the abstract superclass for buildings, facilities, etc. Future extensions of CityGML like bridges and tunnels would be modelled as subclasses of _Site. As subclass of _CityObject, a _Site inherits all attributes and relations, in particular an id, names, external references, and generalization relations. Denotes the relation of a _CityObject to its corresponding _CityObject in higher LOD, i.e. to the _CityObjects representing the same real world object in higher LOD. The GeneralizationRelationType element must either carry a reference to a _CityObject object or contain a _CityObject object inline, but neither both nor none. Type describing the reference to an corresponding object in an other information system, for example in the german cadastre ALKIS, the german topographic information system or ATKIS, or the OS MasterMap. The reference consists of the name of the external information system, represented by an URI, and the reference of the external object, given either by a string or by an URI. If the informationSystem element is missing in the ExternalReference, the ExternalObjectReference must be an URI, which contains an indication of the informationSystem. Specifies the spatial relation of a CityObject realativ to terrain in a qualitative way. The values of this type are defined in the XML file RelativeToTerrainType.xml, according to the dictionary concept of GML3. Specifies the spatial relation of a CityObject realativ to the water surface in a qualitative way. The values of this type are defined in the XML file RelativeToTerrainType.xml, according to the dictionary concept of GML3. Denotes the relation of an _CityObject to its addresses. The AddressPropertyType element must either carry a reference to an Address object or contain an Address object inline, but neither both nor none. Type for addresses. It references the xAL address standard issued by the OASIS consortium. Please note, that addresses are modelled as GML features. Every address can be assigned zero or more 2D or 3D point geometries (one gml:MultiPoint geometry) locating the entrance(s). Denotes the relation of an Address feature to the xAL address element. Type for the implicit representation of a geometry. An implicit geometry is a geometric object, where the shape is stored only once as a prototypical geometry, e.g. a tree or other vegetation object, a traffic light or a traffic sign. This prototypic geometry object is re-used or referenced many times, wherever the corresponding feature occurs in the 3D city model. Each occurrence is represented by a link to the prototypic shape geometry (in a local cartesian coordinate system), by a transforma-tion matrix that is multiplied with each 3D coordinate tuple of the prototype, and by an anchor point denoting the base point of the object in the world coordinate reference system. In order to determine the absolute coordinates of an implicit geometry, the anchor point coordinates have to be added to the matrix multiplication results. The transformation matrix accounts for the intended rotation, scaling, and local translation of the prototype. It is a 4x4 matrix that is multiplied with the prototype coordinates using homogeneous coordinates, i.e. (x,y,z,1). This way even a projection might be modelled by the transformation matrix. The concept of implicit geometries is an enhancement of the geometry model of GML3. Denotes the relation of a _CityObject to its implicit geometry representation, which is a representation of a geometry by referencing a prototype and transforming it to its real position in space. The ImplicitRepresentationPropertyType element must either carry a reference to a ImplicitGeometry object or contain a ImplicitGeometry object inline, but neither both nor none. Type for values, which are greater or equal than 0 and less or equal than 1. Used for color encoding, for example. List for double values, which are greater or equal than 0 and less or equal than 1. Used for color encoding, for example. Used for implicit geometries. The Transformation matrix is a 4 by 4 matrix, thus it must be a list with 16 items. The order the matrix element are represented is row-major, i. e. the first 4 elements represent the first row, the fifth to the eight element the second row,... Used for georeferencing. The Transformation matrix is a 2 by 2 matrix, thus it must be a list with 4 items. The order the matrix element are represented is row-major, i. e. the first 2 elements represent the first row, the fifth to the eight element the second row,... Used for texture parameterization. The Transformation matrix is a 3 by 4 matrix, thus it must be a list with 12 items. The order the matrix element are represented is row-major, i. e. the first 4 elements represent the first row, the fifth to the eight element the second row,... Type for integer values, which are greater or equal than 0 and less or equal than 4. Used for encoding of the LOD number.