A discipline that combines the means to know the location and heading of an aircraft with respect to some map or coordinate system, with guidance which means steering the aircraft along some desired path toward a destination. The construction of the desired path is done with respect to the same a map or coordinate system used for location. In civil aviation, the coordinate system that is becoming a de facto standard is the World Geodetic System of 1984 (WGS-84). This is largely due to the fact that positioning in the Global Positioning System (GPS) is based on this mapping and coordinate system.