1. Department of Geography and Geoinformation Science, NSF Spatiotemporal Innovation Center, George Mason University, Fairfax, VA, USA
2. Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
3. Department of Geography, University of California Santa Barbar, Goleta, CA, USA
4. NASA Goddard, Computational and Information Sciences and Technology Office, Greenbelt, MD, USA