Normalized Difference Vegetation Index (NDVI) is a way of measuring how green and healthy the vegetation is on the Earth’s surface. It is calculated by comparing the amount of near-infrared light (which plants reflect strongly) and red light (which plants absorb) that is reflected by the land cover. NDVI values range from -1 to +1, where higher values indicate more green and dense vegetation, and lower values indicate less or no vegetation.
Sentinel = (B08-B04)/(B08+B04)
Landsat 8-9 = (B118-B062)/(B118+B062)
Firefly = (B118/B022)-1