Toposcopy

Abstract

The new 3D standard CityGML has been attracting a lot of attention in the last few years. Many characteristics of the XML-based format make it suitable for storage and exchange of virtual 3D city models. It provides possibilities to store semantic and geometric information and has the potential to incorporate topological models. A large number of CityGML models are already available in different parts of the world. However, still the creation of a 3D model according to conceptual schema of CityGML remains a challenge. In this paper we present a modeling software Toposcopy, which allows for creating 3D models and exporting them in CityGML format. Toposcopy follows basically a close-range photogrammetric approach to re-constructs 3D models with the help of 2D map and terrestrial geo-referenced images. The approach uses perspective projection to link points on the photos with the corresponding points on the 2D map. A soon as the 3D model is re-constructed, it can be organised according to CityGML spatial schema. Toposcopy appeared to be a handy tool to produce CityGML in LOD 1, 2 and 3. The process of modeling is relatively fast, since various parametric shapes can be applied for a large number of houses. Import and export routines are written, that allows visualizing spatial designs in a 3D topographic data-set. The developed software was tested in several projects. The paper will present the software, the performed tests and will discuss challenges in creating of CityGML features. The paper concludes with suggestions for improving CityGML.