CityValidator is reviewing 3D models

Automated quality control for city models on the Internet

Research on the Computer PNNL
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Whether city planning, tourism, disaster management or navigation - three-dimensional city models are being used by more and more authorities and companies. Now scientists have developed software to check the quality of such models quickly and easily. The CityValidator is free and allows a quality control virtually at the touch of a button.

Three-dimensional city models are being used for more and more applications, for example in tourism to illustrate historical sights, in urban planning for the development of noise and civil protection measures, or by manufacturers of navigation devices to create pedestrian and vehicle navigation systems. The models are increasingly being replaced by the so-called City Geographic Markup Language (CityGML) - an exchange format in which not only the geometry but also the semantics and topology of the three-dimensional objects are taken into account.

Elaborate troubleshooting

"So far, there is no tool to automatically detect missing elements or syntactic errors in the model. The software developers or their customers either have to test the data manually or rely on XML validation services that are hardly suitable for the special requirements of city models, "says Jörg Haist from the Fraunhofer Institute for Computer Graphics (IGD), explaining the initial situation for the project,

With the CityValidator, the scientists at Fraunhofer IGD now offer a tool that specializes in three-dimensional city models that automatically detects such errors at the touch of a button. The CityValidator carries out various tests: "The version released on the Internet checks whether the triangulation in the model is correct, whether there are holes in the geometries and whether the orientation of the triangles is correct, " Haist describes the procedure.

Three automatic test runs

"In addition, we learn whether the buildings are textured - a necessary prerequisite to make a city model really vivid. If all three tests are positive, we can assume that the models are correct and complete. "The previously usual lengthy troubleshooting for data supplier and customer is no longer necessary. In order to be able to adapt the CityValidator for different applications and requirements, the set of rules can be extended by semantic tests, for example, or inserted as a Web Processing Service (WPS) in spatial data infrastructures. display

(Fraunhofer Institute for Computer Graphics, 08.05.2007 - AHE)