M.F. Goodchild and J. Lee. Coverage problems an visibility regions on topographic surfaces . The problem of guarding a polyhedral terrain was first investigated by deFloriani, et al. They showed that finding the minimum number of guards could be done using a set covering algorithm. In this paper, we show that b n 2 c vertex guards are always sufficient and sometimes necessary to guard an n vertex terrain.
Coverage problems an visibility regions on topographic surfaces .