Marines participating in a Corporals Course locate points on a map Sept. 23 during a land navigation course at the Jungle Warfare Training Center, Camp Gonsalves. Due to the jungles thick vegetation and uneven terrain, the corporals had to recognize land developments by looking at contour lines to determine elevation while orientating the map with the environment around them. The Marines are with various units across III Marine Expeditionary Force. (U.S. Marine Corps photo by Lance Cpl. Ryan C. Mains/Released)