1. Institute of RS and GIS, Peking University, Beijing, China
2. Beijing Key Laboratory of Spatial Information Integration & Its Applications, Beijing, China
3. State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing, China
4. Jackson School of Geosciences, the University of Texas at Austin, Austin, TX, USA
5. School of Civil Engineering and Environmental Science, University of Oklahoma, USA