Normalized Difference Vegetation Index (NDVI)
 |
As shown here, a stressed leaf and a healthy leaf reflect nearly the same amount of blue, green, red light, but a healthy leaf reflects more NIR light.
|
NDVI is a commonly used vegetation index to quantify plant health. Its formula:
NDVI = (NIR - Red) / (NIR + Red)
NDVI values between -1 and 0 correspond to non-vegetation surfaces such as road, water, or soil. Soil's value is close to 0. Plant values range from 0.1 to 1. The higher the NDVI value, the greater their density and health.
NDVI Map of Vegetation Field captured by Parrot Sequoia camera
Typically, a multispectral orthomosaic map is represented in a form of NDVI values from -1 to 1 (-1 is shown as red and 1 as green).
Sample of Multispectral Imagery captured by MicaSense Multispectral Camera
 |
RGB Color |
 |
Chlorophyll Map |
Applications of Multispectral Imagery in Farming
• |
Identify pests, disease and weeds at early stage. NDVI enables agronomists and farmers to see stressed crops in a field earlier before the human eye would be able to detect. |
• |
Provide data on soil fertility and refine fertilization by detecting nutrient deficiencies. |
• |
Count plants and determine population or spacing issues. |
• |
Measure irrigation, survey farm boundary, classify landuse.
|