Efficient observer siting on large terrain cells (extended abstract)

This paper refines our testbed implementation of a suite of programs, for fast viewshed, and for fast approximate visibility index determination, and for siting multiple observers jointly to cover terrain. We process DEMs up to 2402 × 2402, while executing so quickly that multiple experiments are easily possible. Both the observer and target may be at a given fixed height above the terrain. We conclude that estimating visibility index using 20-30 random targets per observer is a good compromise between speed and quality. When forcing the selection of top observers to be well spaced out, subdividing the cell into such small blocks that only 2-5 observers are selected per block is best. Applications of multiple observer siting include radio towers, terrain observation, and mitigation of environmental visual nuisances.