Variable Resolution Terrain Surfaces

A model for the multiresolution decomposition of planar domains into triangles is introduced, which is more general than other multiresolution models proposed in the literature, and can be eeciently applied to the representation of a polyhedral terrain at variable resolution. The model is based on a collection of fragments of plane triangulations arranged into a partially ordered set. Diierent decompositions of a domain can be obtained by combining diierent fragments from the model. A data structure to encode the model is presented, and an eecient algorithm is proposed that can extract in linear time a polyhedral terrain representation, whose accuracy over the domain is variable according to a given threshold function. Furthermore, the size of the extracted representation is minimum among all possible polyhedral representations that can be built from the model, and that satisfy the threshold function. A major application of these results is in real time rendering of terrains in ight simulation.