Fig. 7From: Mapping the forage nitrogen, phosphorus, and potassium contents of alpine grasslands by integrating Sentinel-2 and Tiangong-2 dataSpatial predictions of nitrogen (N) (a–c), phosphorus (P) (d–f), and potassium (K) (g–i) in July, September, and November 2017 using optimal estimation models (Fig. 5). The white area is where the nongrassed areas and clouds were removedBack to article page