Required processing:
Correction and smoothing of DEM, extraction of visibility points (relative min and max of the area), generation of a grid;
Launch visibility script over the whole area which computes visibility value from all other pixels (CPU time consuming).
Data requirements:
Digital Elevation Model (DEM)
Georeferenced image of the visibility
Why using remote sensors?:
The purpose of such analysis is to identify the areas of a region of interest from which the best visibility of the surroundings can be achieved.
Knowing this might of help in reconstructing the military positions and hence in locating possible minefields.