1. School of Geography and Ocean Science, Nanjing University, Nanjing, China
2. Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing University, Nanjing, China
3. Jiangsu Provincial Key Laboratory of Resources and Environmental Information Engineering, China University of Mining and Technology, Xuzhou, China
4. School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou, China