Optimizing kNN for Mapping Vegetation Cover of Arid and Semi-Arid Areas Using Landsat Images. - Hua Sun 002; Qing Wang 012; Guangxing Wang; Hui Lin 004; Peng Luo; Jiping Li; Siqi Zeng 003; Xiaoyu Xu; Lanxiang Ren (Remote. Sens., 2018)