 Surveys enabled the artillery to ensure the accuracy of fire, but as artillery units moved to more remote areas it became more difficult to support friendly units because surveys were lacking.In early 1967, Lt. Col. Arthur L. Benton, the former chief of the Mapping and Intelligence Section of the Engineer Sections, United States Army Vietnam, who had returned to Vietnam on temporary duty from the Army Map Service in Washington, DC, developed a system known as photogrammetric positioning.By tying aerial photographs to base maps, artillery surveyors could readily obtain azimuth and location of firing positions.