Advanced Computer Graphics Project Report Terrain Approximation

DEM datasets are getting larger and larger with increasing precision, so that approximating DEM can be useful in some situations. Conventional terrain simplification algorithms try to minimize the elevation error between the simplified and the original terrains [3]. This project tries to minimize the visibility error in terrain approximation. The error metric is defined as the average viewshed error of a number of random viewpoints over the terrain. In order to minimize the error, the viewshed computed on the approximated terrain should be as close as possible to the viewshed computed on the original terrain. One possible way of keeping the viewshed is to keep the points defining the viewshed, which can be identified by computing viewsheds at all points of the terrain. This information can be used in triangulation to compute approximations of the terrain. The method is compared with the maximum elevation error based triangulation for the average viewshed error.