Airmen 1st Class Michael Rusnak, Jacob Mason and Robert Corfield, 28th Civil Engineer Squadron survey technicians, prepare to collect geographic coordinate data with survey rods and global positioning systems technology at Ellsworth Air Force Base, S.D., March. 6, 2012. Information is recorded and collected with GPS devices to ensure the most accurate, up-to-date map of the base are available. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)