ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Publications Copernicus
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Articles | Volume IV-4
https://doi.org/10.5194/isprs-annals-IV-4-59-2018
https://doi.org/10.5194/isprs-annals-IV-4-59-2018
19 Sep 2018
 | 19 Sep 2018

DETECTION AND EVALUATION OF TOPOLOGICAL CONSISTENCY IN CITYGML DATASETS

A. Giovanella, P. E. Bradley, and S. Wursthorn

Keywords: Topology, Topological Consistency, CityGML, 3D Model, Spatial Database, Polygon, Geometry

Abstract. The topological consistency of Boundary-Representation models, meaning here that the incidence graph is homeomorphic with the underlying topology of geographical data, is checked for several CityGML datasets, and a first classification of topological inconsistencies is performed. The analysis is carried out on a spatial database system into which the datasets have been imported. It is found that real-world datasets contain many topologically inconsistent pairs of intersecting polygons. Also data satisfying the ISO/OGC standards can still be topologically inconsistent. In the case when the intersection is a point, topological inconsistency occurs because a vertex lies on a line segment. However, the most frequent topological inconsistencies seem to arise when the intersection of two polygons is a line segment. Consequently, topological queries in present CityGML data cannot rely on the incidence graph only, but must always make costly geometric computations if correct results are to be expected.