Real-time manipulation of 3D terrain models

The sheer volume of data inherent to geographic databases tends to stifle performance of spatial data manipulations such as cartographic analysis and visualization. Optimized algorithms using spatial filters can improve this performance by reducing the amount of data that must be processed. In this paper we demonstrate how a hierarchical triangulated terrain model supports such optimizations. The model's tree structure represents a different level of detail at every depth level, thereby providing rapid access to and generalizations of all or part of the terrain model. Here we describe three algorithms that exploit this structure for improved performance of the following visualization and analysis applications: zoom, multi-resolution views, and line-of-sight. -Authors