Automatic assembling of cadastral maps based on generalized hough transformation

There are numerous cadastral maps generated by past land surveying. The raster digitization of these paper maps is in progress. For effective and efficient use of these maps, we have to assemble the set of maps to make them superimposable on other geographic information in a Geographic Information System. The problem can be seen as a complex jigsaw puzzle where the pieces are the cadastre sections extracted from the map. We present an automatic solution to this geographic jigsaw puzzle, based on the generalized Hough transformation that detects the longest common boundary between every piece and its neighbors. The experiments have been conducted using the map of Mie Prefecture, Japan and the French cadastral map. The results of the experiment with the French cadastral maps show that the proposed method, which consists of extracting an external area and extracting and regularizing the north arrow, is suitable for assembling the cadastral map. The final goal of the process is to integrate every piece of the puzzle into a national geographic reference frame and database.