NASA's Land, Vegetation, and Ice Sensor (a.k.a. the Laser Vegetation Imaging Sensor) or "LVIS", is a scanning laser altimeter instrument that is flown, by aircraft, over target areas to collect data on surface topography and vegetation coverage.
The LVIS, which also includes data from an integrated inertial navigation system (INS) and global positioning system (GPS), is designed, developed and operated by the Laser Remote Sensing Laboratory, at Goddard Space Flight Center.
Example of LVIS Scan and Beam Pattern
This image shows the LVIS scan and beam pattern. The unique LVIS scanning system generates this pattern that evenly and completely samples the surface below. There are approximately 100 beams across the 2 km wide swath. The colors represent the surface elevation (blue is low, yellow/white is high). The slight undulations at the top and bottom edges are a result of the aircraft roll. (Click image for Hi-res version)