Abstract: A device executing intervisibility calculation includes a mechanism executing a radial spoke scan pattern where individual radials are traversed beginning at a threat installation and extending outward along a radial to a distance corresponding to threat range capability. Intervisibility calculation is simplified to allow implementation in a simple, dedicated hardware engine to provide rapid execution time while ensuring accurate intervisibility results. The intervisibility engine includes lookup tables to provide precalculated data and advantageously avoids divide operations whereby the intervisibility calculation may be executed by use of a series of adds, subtracts, and multiplies relative to intervisibility data developed while traversing a given radial. The engine calculates a slope for each data post visited in traversing a radial, and identifies a data post as being visible when its associated slope is greater than a previously encountered greatest magnitude slope.