A route data base generating system avoids GPS satellite signals sources for land based vehicle azimuth and heading determinations in areas where reception of the satellite signals is unavailable or impaired and relies on vehicle part movements that are equatable to the heading and azimuth changes of the vehicle for determining such vehicle orientations. Part movements equatable to the heading changes are found in the vehicle wheel assemblies. A route data base founded on interconnecting linear route segments that are arranged in and end-to-end serial order is advocated and wherein the angular deviation between connecting segments in the order is predetermined. Various uses of the generating systems and related procedures are advocated for both on-the-road and off-road usage.