1. Key Lab of Geographical Information Science, Ministry of Education; East China Norm University; Shanghai China
2. School of Geographic Sciences; East China Normal University; Shanghai 200241 China
3. Center of Integrated Geographic Information Analysis, School of Geography and Planning; Sun Yat-sen University; Guangzhou China
4. Guangdong Key Laboratory for Urbanization and Geo-simulation; Guangzhou China
5. Guangdong Provincial Engineering Research Center for Public Security and Disaster, ; Guangzhou China
6. Department of Computer Science & Information Systems, College of Business; University of North Alabama; UNA Box 5217, One Harrison Plaza Florence AL 35632-0001