Automatic Extraction and Structuring of Objects from Scanned Topographical Maps — An Alternative to the Extraction from Aerial and Space Images ?

This paper presents investigations and developments in the area of automatic extraction of cartographic features from scanned topographic maps. It focuses on the recognition and extraction of buildings for the establishment of topographic and cartographic information systems or for the provision of information supporting the automatic extraction of man-made objects from aerial or space images. The described solution combines knowledge-based pattern recognition techniques, raster data processing operations and raster-vector conversion procedures based on robust estimation and constrained adjustment techniques. Following a stringent quality control process the structured results can be exported in a selection of formats. The implemented solution allows largely automatic processing of entire map sheets with very high success rates within a few hours using standard UNIX workstations. Finally, the paper presents results from applications of the technology such as the recognition of buildings for the simulation and design of mobile communication networks for Swiss PTT.