CityGML is a common information model for the representation of 3D urban objects. It defines the classes and relations for the most relevant topographic objects in cities and regional models with respect to their geometrical, topological, semantical and appearance properties. Included are generalization hierarchies between thematic classes, aggregations, relations between objects, and spatial properties. These thematic information go beyond graphic exchange formats and allow to employ virtual 3D city models for sophisticated analysis tasks in different application domains like simulations, urban data mining, facility management, and thematic inquiries.
Activities that would benefit from the richness of CityGML data include city planning, real estate, insurance, architectural design, environmental simulation, mobile telecommunication, disaster management, homeland security, facilities management, vehicle and pedestrian navigation, training simulators and others. CityGML will play an important role in the use of Building Information Models (BIM) to improve interoperability among the information systems used in the many domains of activity that involve design, construction, ownership and operation of buildings and capital projects.