LIDAR

http://forsys.cfr.washington.edu/JFSP06/lidar_&_ifsar_tools.htm

Light detection and ranging is an active remote sensing that transmits its own sensor to the object, and in turn, the radiation bounces back to the sensor. This allows the sensor to have a better visual understanding of the area. The map above has fused LIDAR with a more traditional 2-D form of imagery to produce a higher quality image of the Blue Ridge site surface.