Multi-scale rendering with geometry collapse and a symbol knowledge base

This paper discusses a novel methodology for multi-scale rendering of geographic features depending upon changes in visual scale. The methodology consists of geometry collapse and a symbol knowledge base. Two collapse algorithms are implemented: polygon to point and polygon to line. In particular, we develop a partial collapse algorithm for linear features. A river is represented by lines and polygons depending on the width. To render features with scale changes, a symbol knowledge base is designed to specify scale ranges and symbols for each feature. Finally, a multi-scale rendering tool is developed and applied to the map of Camp Lejune, NC. The symbols in the knowledge base can be accumulated and adapted for various mapping applications.