Terrain intervisibility-believe it or not?

Intervisibility displays serve a valuable function. But to build and use these systems wisely, it´s good to understand the errors and limitations involved. At LMFS, we have integrated digital maps from other companies into avionics systems such as Army Special Operations Aircraft and MH53J, and have analyzed the errors associated with the use of level 1 and level 2 terrain elevation data from National Imagery and Mapping Agency (NIMA). We have also developed a number of realtime intervisibility and probabilistic intervisibility functions using a hybrid of multi-resolution techniques and algorithms to obtain the best results possible for a given set of computer resources. This paper explores some of the problems, solutions, and human/machine interface considerations associated with the generation and use of intervisibility