Line simplification and digital cartographic databases.

摘要

This thesis examines one component of the cartographic generalization process, line simplification, and its implementation with computer technology. The effectiveness of line simplification techniques in producing useful maps from digital map data is studied. Many techniques have been proposed to simplify lines; several of these have been implemented here. The approaches have been compared on their ability to simplify lines from two cartographic databases over both modest and extreme changes in scale. The comparisons are based on the simplification of individual lines, on the production of complete maps, and on mathematical measures of performance. One promising technique is enhanced to overcome certain limitations which are apparent during extreme scale change. The effect of map projections on the performance of such techniques is considered. While much additional work is needed, this study indicates that line simplification techniques can extend the range of scales over which certain cartographic databases can be utilized. 124 refs.