A vegetation index (also called a vegetative index) is a single number that quantifies vegetation biomass and/or plant vigor for each pixel in a remote sensing image. The index is computed using several spectral bands that are sensitive to plant biomass and vigor.
The most common vegetation index is the normalized difference vegetation index (NDVI). NDVI compares the reflectance values of the red and near-infrared regions of the electromagnetic spectrum using the following formula:
NDVI=NIR-RED/NIR+RED
NIR is the pixel's reflectence value in the near-infrared band
RED is the pixel's reflectence value in the red band
The NDVI value, which ranges from -1.0 to 1.0 for each pixel in an image, helps identify areas of varying levels of plant biomass/vigor. Higher values indicate high biomass/high vigor.
