Normalized Difference Vegetation Index, or NDVI, is a measurement of the ratio of visible to infrared light that is reflected by a plant. The pigment in plant leaves, chlorophyll, strongly absorbs visible light while strongly reflecting infrared light. Thus,  the higher the ratio between absorbed visible light and reflected infrared light, the more chlorophyll is in the plant. This is why NDVI is used to measure plant vigor.

The formula to compute NDVI is relatively simple:
NDVI Value = (Infrared - Visible) ÷ (Infrared + Visible)

The resultant values are between 0 and 1, with close to 0 being barren rock, and close to 1 being tropical rainforest. Typical ground reflectance calibrated NDVI values for agricultural applications range from 0.2 to 0.8. Higher NDVI values generally mean more leaves, but VineView understands that ideal vigor levels can vary by location and management goals. This is why we offer "relative to ideal" NDVI maps: show us where your ideal plants are, and we can show you how the rest of your crop compares.