A method for forming a virtual tripwire through a subregion of an area of interest. The method may involve performing a geometric analysis of terrain in the subregion, the geometric analysis determining a location for each one of a pre-designated plurality of candidate sensors that may potentially be used in forming the virtual tripwire. A viewshed for each candidate sensor is determined. Each viewshed represents a coverage region for its associated candidate sensor. A geometric beginning point and a geometric end point within the subregion are each defined for the virtual tripwire. The viewsheds are analyzed to determine a number of the candidate sensors required to form a path for the virtual tripwire from the beginning point to the end point.