LIDAR

http://www.noaanews.noaa.gov/stories/s798.htm

Standing for Light Detection and Ranging, LIDAR is a technique using a powerful laser to measure some distance. This has a large variety of applications from measuring the distance across geographic locations, determining the height or depth of various physical features on the Earth, and even judging the distance between entire stars and other planetary bodies. This graphical analysis shown used a LIDAR mounted on aircraft, in the service of NOAA, to determine the landscape of Ground Zero following the September 11^th terrorist attacks.