Animation depicting a laser pulse leaving from a LIDAR instrument onboard a satellite. The pulse hits the ground and returns to the instrument. A counter indicates the measurement of the time it took the pulse to make its trip.
Animation depicting LIDAR instrumentation onboard a satellite making multiple measurements as it passes over a landscape. A graph showing the measurements is overlaid, showing how the instrument is effectively making a "map" of the landscape from space.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 22.214.171.124.0