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 may make use of 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 may also be used for defining a swath of the area of interest, the swath representing a subregion laying over, or adjacent to, a border to be monitored. A display may be 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.