1. School of Software, Shandong University, Jinan, China
2. C-FAIR, Shandong University, Jinan, China
3. School of Computer Science and Engineering, Nanyang Technological University, Singapore, Singapore
4. School of Geography and Information Engineering, China University of Geosciences, Wuhan, China
5. Center for Spatial Information Science, The University of Tokyo, Chiba, Japan
6. Geospatial Data Science Lab, Department of Geography, University of Wisconsin-Madison, Madison, WI, USA