Fig. 2. Normalized difference vegetation index (NDVI) and visible atmospherically resistant indices (VARI_Green and VARI_{Red Edge}) vs. green vegetation fraction of maize during the 2002 growing season, before silking. Normalized difference vegetation index showed a nonlinear relationship with green vegetation fraction while VARI showed linear relationships, with VARI_Green having a higher dynamic range to allocate green vegetation fraction values than VARI_{Red Edge}.