1. Ph.D. Candidate, School of Resources and Environmental Sciences, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China.
2. Associate Professor, Dept. of Geography, Kent State Univ., Kent, OH 44242.
3. Professor, School of Resources and Environmental Sciences, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China; Professor, Key Laboratory of GIS, Ministry of Education, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China; Professor, Key Laboratory of Digital Mapping and Land Information Application Engineering, National Administration of Surveying, Mapping and Geoinformation, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China.
4. Professor, School of Resources and Environmental Sciences, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China; Professor, Key Laboratory of GIS, Ministry of Education, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China; Professor, Key Laboratory of Digital Mapping and Land Information Application Engineering, National Administration of Surveying, Mapping and Geoinformation, Wuhan Univ., 129 Luoyu Rd., Wuhan 430079, China (corresponding author).