1 State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Science and Natural Resource Research, Chinese Academy of Sciences, 11A, Datun Road Anwai, Beijing, 100101, China.
2 School of Geography and Information Engineering, China University of Geosciences, Wuhan, 430074, China.
3 State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Science and Natural Resource Research, Chinese Academy of Sciences, 11A, Datun Road Anwai, Beijing, 100101, China. xucd@lreis.ac.cn.
4 University of the Chinese Academy of Sciences, Beijing, 100049, China. xucd@lreis.ac.cn.