An aerial photograph of Simi Valley, California, was obtained. This snapshot was taken by an airplane flying at a known altitude and archived. This photo was available to a second airplane whose position is to be determined. Equipped with a downward looking telescope, the second airplane flies at the same altitude as the first airplane. The problem addressed in this chapter is that of locating the position of the second airplane with respect to the original aerial photo by comparing the telescope image with the aerial photo. The aerial photo is like a map. The second airplane is able to locate its position on the map. This method, based on cognitive memory, can be exercised repeatedly, producing a track of the second airplane on the map. Comparison of the telescopic image with the map image involves translation and rotation with the goal of seeking a ‘hit’. If the second airplane was flying at an altitude other than that of the first airplane, a scale change would be required.