Staff Sgt. Brent Wade, 3rd platoon sergeant, and 2ndLt. Ryan C. Spangler, 3rd platoon commander, with Charlie Company, 2nd Assault Amphibian Battalion, give their Marines suggestions on what they can do better in their next terrain model at Fort A.P. Hill, Va., June 2, 2013. A terrain model is a physical model of an area on a map and is used for strategic purposes. - Staff Sgt. Brent Wade, 3rd platoon sergeant, and 2ndLt. Ryan C. Spangler, 3rd platoon commander, with Charlie Company, 2nd Assault Amphibian Battalion, give their Marines suggestions on what they can do better in their next terrain model at Fort A.P. Hill, Va., June 2, 2013. A terrain model is a physical model of an area on a map and is used for strategic purposes.