For topographic processing, a plurality of maps are stored, the maps being of different scales and therefore being based on different amounts of map data. The user selects a map of appropriate scale, and can then select a part, for example a line, on which appropriate analysis is to be made, such as...http://www.google.de/patents/US5444618?utm_source=gb-gplus-sharePatent US5444618 - Apparatus and method for topographic processing
