Leclerc, Y. G., & Lau, S. Q. (1994). TerraVision: A terrain visualization system. SRI International, Technical Note, 540, 20.
A system for interactively viewing terrain data is described. The terrain data comprises elevation information and specially processed aerial or satellite images. The system, called TerraVision, uses a multi-resolution representation of the terrain data divided into equal-sized subimages called tiles. The tiles are stored in a database that is typically dis tributed across a high-speed network for fast parallel access. This distribution of data allows for the construction of very large databases that can be maintained remotely (a large database is defined here as one containing more 1 million polygons and 1GByte of imagery). This representation, in conjunction with a course-to-fine search algorithm, allows TerraVision to render very large terrain databases in ’interactive times’ (10-30 frames per second). Furthermore, TerraVision’s architecture is designed to accomodate the lost or delayed tiles that are inherent in network database access without interfering with the user’s ability to roam about the terrain at will.