Extracting Topographic Features for Outdoor Mobile Robots

Some applications such as the autonomous navigation in natural terrain and the automation of map making process require high-level scene descriptions as well as geometrical representation of the natural terrain environments. In this paper, we present methods for building high level terrain descriptions, referred as topographic maps, by extracting terrain features like "peaks", "pits", "ridges", and "ravines" from the contour map. The resulting topographic map contains the location and type of terrain features as well as the ground topography. We develop new definitions for those topographic features based on the contour map. We build a contour map from an elevation map and generate the connectivity tree of all regions separated by the contours. We use this connectivity tree, called Topographic Change Tree, to extract the topographic features. Experimental results on a Digital Elevation Model (DEM) supports our definitions for topographic features and the approach.