1. a Center of Information & Network Technology , Beijing Normal University , Beijing, 100875, China
2. b State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Institute of Remote Sensing Applications , Chinese Academy of Sciences and Beijing Normal University , Beijing, 100875, China
3. c College of Resource Science & Technology , Beijing Normal University , Beijing, 100875, China
4. d Naval Armament Academy , Beijing, 100036, China
5. e Institute of GIS, PASCO Corp , Tokyo, 153–0043, Japan