Continuous fields of land cover for the conterminous United States using Landsat data: First results from the Web-Enabled Landsat Data (WELD) project - Hansen, M.C.; Egorov, Alexey; Roy, David; Potapov, P.; Ju, J.; Turubanova, S.; Kommareddy, I.; Loveland, Thomas R. (Remote Sensing Letters, 2011)