1. College of Mathematics and Computer Sciences, Zhejiang A&F University, Hangzhou 311300, China
2. Sichuan Forestry and Grassland Survey and Planning Institute, Chengdu 610084, China
3. Zhejiang Provincial Key Laboratory of Forestry Intelligent Monitoring and Information Technology, Zhejiang A&F University, Hangzhou 311300, China
4. Institute of Remote Sensing and Geographic Information System, School of Earth and Space Sciences, Peking University, Beijing 100871, China