Red Edge NDVI (RENDVI) estimates vegetation health and vigor by utilizing the red-edge spectral band, which is highly sensitive to changes in chlorophyll content. It is particularly effective during mid to late stages of crop growth when chlorophyll concentrations are high. RENDVI values range from -1 to +1, where higher values indicate healthier, more vigorous vegetation. It is useful for monitoring crop development, optimizing fertilizer use, and assessing yield potential.

Firefly = (B118-B075)/(B118+B075)
Sentinel = (B08-B05)/(B08+B05)