1. U.S. Geological Survey, Menlo Park, CA 94025, USA.
2. California Institute of Technology, Pasadena, CA 91106, USA.
3. National Center for Airborne Laser Mapping, University of Houston, Houston, TX 77204, USA.
4. Jet Propulsion Laboratory, La Cañada Flintridge, Pasadena, CA 91109, USA.
5. Carnegie Mellon University–Silicon Valley, Moffett Field, CA 94035, USA.