1. Associate Professor, Dept. of Geographical Information Science, Nanjing Univ., Nanjing 210093, P.R. China.
2. Professor, Geoinformation Science and Engineering College, Shandong Univ. of Science and Technology, Qingdao 266510, P.R. China.
3. Associate Professor, Jiangxi Administration Institute, Nanchang 330003, P.R. China.
4. GPS Analyst, Geospatial and Earth Monitoring Division, Geoscience Australia, ACT 2601, Australia.
5. Assistant Professor, Dept. of Civil and Geomatics Engineering, California State Univ., Fresno, CA 93740-8030 (corresponding author).