1. School of Geography, Nanjing Normal University, Nanjing, China
2. Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing, China
3. Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, China
4. School of Remote Sensing & Geomatics Engineering, Nanjing University of Information Science & Technology, Nanjing, China
5. Department of Geoinformatics – Z_GIS, University of Salzburg, Salzburg, Austria