The normalized difference vegetation index (NDVI) is a simple graphical indicator that can be used to analyze remote sensing measurements, often from a space platform, assessing whether or not the target being observed contains live green vegetation.
By comparing visible and infrared light, scientists measure the relative amount of vegetation. ... NDVI is calculated from the visible and nearinfrared light reflected by vegetation. Healthy vegetation (left) absorbs most of the visible light that hits it and reflects a large portion of the nearinfrared light.
NDVI=(NIRR)/(NIR+R)
NDVI VALU +1 TO 1