Current TAWS systems generally do not provide alerts based on structures or wire obstacles. Such structures and wire obstacles include transmission and electrical wires, and power lines, bridges, and buildings. The current system allows just such alerting. Such alerts are particularly useful for helicopter aircraft, which commonly fly at heights where such structures and obstacles are present near the normal flying altitude of the aircraft. Certain implementations of the system and method include a method of creating an obstacle for use in a terrain awareness warning system, including: receiving data about a first terminus of an obstacle; receiving data about a second terminus of the obstacle; constructing a virtual volume about the first and second termini and a volume therebetween; and storing the virtual volume, whereby a database may be constructed of virtual volumes for use in addition to terrain information to provide alerting on obstacles for an aircraft.