Visualizing large terrain in desktop environment

We describe several implementation aspects on generating a terrain representation from a digital elevation model (DEM) and visualizing scene from that representation on desktop environment. Most of terrain data is too huge to cram into system memory in low-end computer. Consequently, we must use secondary storage device as a part of system memory at run time. However, dynamic loading of data from a disk is relatively slow, in order to speed up access of terrain data on disk, we use two disk access mechanism: spatial clustering and smart pointer. For spatial clustering, we present a directory structure with Hana code as a key. And with smart pointer, we present an object access method, which can access objects regardless of each stored location. We represent an approximated terrain model generation algorithm which utilize our methods, and a region selective rendering algorithm which can retrieve each queried region.