“Normalized Difference Vegetation Index (NDVI) quantifies vegetation by measuring the difference between near-infrared (which vegetation strongly reflects) and red light (which vegetation absorbs).”
Normalized Difference Vegetation Index
NDVI is a range that spans from -1 to +1, without a clear boundary for each land cover type. Negative NDVI values are indicative of water, whereas values near +1 are likely to indicate dense green foliage.
Conversely, NDVI values near zero suggest a lack of green vegetation, which could even point to an urbanised area.
Despite its broad application in remote sensing, there are still essential considerations regarding how to calculate NDVI, what NDVI values signify, and how Earth scientists apply this index.
How do you calculate NDVI?
NDVI (Normalized Difference Vegetation Index) is a commonly used index for quantifying vegetation coverage and growth. NDVI is calculated from the reflectance values of red and near-infrared (NIR) wavelengths of electromagnetic radiation.
Vegetation that is healthy and has sufficient chlorophyll content reflects more near-infrared (NIR) and green light when compared to other wavelengths. However, it absorbs more red and blue light. The human eye perceives vegetation as green due to this phenomenon. If we were able to detect near-infrared, we would observe that vegetation appears strong in that wavelength range as well.
Both Landsat and Sentinel-2 satellite sensors have bands that include the necessary near-infrared and red wavelengths for detecting vegetation.
How do we use NDVI?
NDVI is utilized in various fields such as agriculture, forestry, and environmental monitoring.
In agriculture, NDVI is widely used for precision farming and estimating…