Update of Roads in Gis from Aerial Imagery: Verification and Multi-resolution Extraction

Aerial imagery is an important source for the acquisition and update of GIS data. By using digital imagery it is possible to automate some parts of these tasks. In this context this paper proposes a new approach for the automatic update, i.e., verification and extraction, of roads from aerial imagery. The verification process evaluates road axes from GIS data based on the analysis of profiles taken perpendicularly to the axes. It is possible to handle inaccurate axes, as well as to detect initial points for branching roads. The process for the extraction of roads is independent of the GIS data, but relies on knowledge about roads provided by a road model. This model comprises knowledge about geometrical, radiometrical, topological, and contextual properties of roads at different resolutions. Multi-resolution extraction is applied because distinct characteristics of roads can be detected best at different resolution levels. By fusing results of different resolution levels the distinct characteristics of roads are integrated. Examples for the verification as well as the road extraction are given.