Infantry have much greater local situational awareness than other military forces, due to their inherent intimate contact with the battlefield ("boots on the ground"); this is vital for engaging and infiltrating enemy positions, holding and defending ground (any military objectives), securing battlefield victories, maintaining military area control and security both at and behind the front lines, for capturing ordnance or materiel, taking prisoners, and military occupation. Infantry can more easily recognise, adapt and respond to local conditions, weather, and changing enemy weapons or tactics. They can operate in a wide range of terrain inaccessible to military vehicles, and can operate with a lower logistical burden. Infantry are the most easily delivered forces to ground combat areas, by simple and reliable marching, or by trucks, sea or air transport; they can also be inserted directly into combat by amphibious landing, or for air assault by parachute (airborne infantry) or helicopter (airmobile infantry). They can be augmented with a variety of crew-served weapons, armoured personnel carriers, and infantry fighting vehicles.