Efficient large-scale vegetation mapping at the formation level using multi-source data: A case study in Beijing, China - Jiachen Xu; Yongmei Huang; Kai Cheng; Yi Wang; Tianyu Hu; Hongcan Guan; Yuling Chen; Yu Ren; Mengxi Chen; Zekun Yang; Jiarui Wang; Qinghua Guo (ISPRS Journal of Photogrammetry and Remote Sensing, 2025)