1. A software module apparatus for enabling a user to generate a virtual tripwire through a geographic area of interest using a plurality of sensors, the apparatus comprising: an input for allowing a user to input a digital elevation model (DEM) of the area of interest; an input responsive to a user controlled device for defining a swath of the area of interest, the swath representing a subregion laying over, or adjacent to, a border to be monitored; and a display generated for illustrating computed locations of a plurality of independent sensors used to form the virtual tripwire through the swath of the area of interest.