Multi-level representation of terrain features on a contour map

Contour lines are important for quantitatively displaying relief and identifying morphometric features on a map. Contour trees are often used to represent spatial relationships between contours and assist the user in analysing the terrain. How- ever, automatic analysis from the contour tree is still limited as features identified on a map by sets of contours are not only characterised by local relationships be- tween contours but also by relationships with other features at different levels of representation. In this paper, a new method based on adjacency and inclusion re- lationships between regions defined by sets of contours is presented. The method extracts terrain features and stores them in a feature tree providing a description of the landscape at multiple levels of detail. The method is applied to terrain analysis and generalisation of a contour map by selecting the most relevant features accord- ing to the purpose of the map. Experimental results are presented and discussed