Why in News?

• Normalized Difference Vegetation Index (NDVI) estimates the density of vegetation and amount of food abundance available for herbivorous animals, for example, elephants.
• This index has a negative correlation with graminoids (grassy food – grasses, sedges, and rushes – preferentially consumed by elephants) in tropical forests.

Highlights:

• NDVI calculates the difference between the red and near infrared components of light reflected by objects (like satellite).
• Since healthy vegetation strongly absorbs red and reflects near-infrared light, this difference can indicate the presence of healthy vegetation and can be mapped into a colour code (green and red).
• High NDVI value (bright green) indicates healthier vegetation whereas low value (red) indicates less or no vegetation.
• Data obtained from satellites (like Sentinel-2, Landsat and SPOT) that produce red and near-infrared images are used for estimating NDVI.

Applications of the Index:

• Foresters use NDVI to quantify forest supply and leaf area index.
• Farmers use NDVI for precision farming and to measure biomass.
• NDVI is used to inform the ecology of various species, from elephants and red deer to mosquitoes and birds.
• NASA states that NDVI is a good indicator of drought when water limits vegetation growth, it has a lower relative NDVI and density of vegetation.