A method of generating an elevation database for selected geographic regions, the method comprising: receiving a location database, a rule database, and an input elevation database, each location in the location database being located within a selected geographic region; constructing, for each location in the location database and using rules from the rule database, a bounding region enclosing a continuous geographic region; applying elevation data from the input elevation database to each bounding region; and compressing the elevation data in each bounding region to provide compressed elevation data; wherein, upon decompressing the compressed elevation data, each point in each bounding region represents a level of elevation at that point in the associated selected geographic region.