1. The Key Laboratory of Virtual Geographic Environment, Ministry of Education, Nanjing Normal University, Nanjing, China
2. The State Key Laboratory Cultivation Base of Geographical Environment Evolution, Nanjing, China
3. The Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Jiangsu Province, Nanjing, China
4. The Qinghai Provincial Basic Surveying and Mapping Institute, Xining, China