Checking 3D City Models

City Doctor is a comprehensive tool for the validation of CityGML-based virtual 3D city models.

Due to the complexity of the topic we distinguish  between the three areas of syntax, semantics and geometry.

• The syntax check ensures that the read data is conformant to the OGC standard document for CityGML 2.0.
• The geometric validation consists of two categories. Buildings are considered as a whole as solid bodies (solid elements) or only with their boundary surfaces (polygonal elements).
• The semantic check includes plausibility checks of attributes relating to geometry. For example, the building height is compared with the number of floors of a building. Another test checks all semantic elements of the model, if the roof surfaces are directed against the sky (orientation of the boundary surfaces).