Available with Image Server
The normalized difference vegetation index (NDVI) is a standardized index that allows you to generate an image displaying greenness, also known as relative biomass. This index takes advantage of the contrast of characteristics between two bands from a multispectral raster dataset—the chlorophyll pigment absorption in the red band and the high reflectivity of plant material in the near-infrared (NIR) band.
Extremely low or negative values represent areas with no vegetation at all, such as cloud, water, or snow. Very low values represent areas of little to no vegetation, such as concrete, rock, or bare soil. Moderate values represent areas of shrubs and grassland. High values represent forest areas and lush vegetation.
Notes
The default equation used to generate the output is as follows:
NDVI = ((IR - R)/(IR + R)) * 100 + 100This results in a value range of 0 to 200. This value range fits within an 8-bit data structure, which can be rendered with a specific color ramp or color map.
To view the scientific pixel values of -1.0 to 1.0, use the Scientific Output option.
You can use the NDVI Colorized function to apply a color map directly to the result.
Parameters
| Parameter | Description |
|---|---|
Raster | The input multispectral raster. |
Visible Band ID | Specifies the band ID that represents the red part of the electromagnetic spectrum. |
Infrared Band ID | Specifies the band ID that represents the near-infrared part of the electromagnetic spectrum. |
Scientific Output | The output values will range from -1.0 to 1.0, which is used in many scientific applications. |
Learn more about NDVI
The NDVI process creates a single-band dataset that mainly represents vegetation density and vigor. The differential reflection in the red and infrared (IR) bands allows you to monitor density and relative vigor of vegetation growth using the spectral reflectivity of solar radiation. Healthy vegetation commonly exhibits higher reflection in the near-infrared wavelength range than in the red wavelength range. When leaves are water stressed, diseased, or dead, they become more yellow and reflect significantly less in the near-infrared range. Infrared wavelengths are absorbed by clouds, water, and snow, and they are reflected similarly as the red band by rock and bare soil. The negative values represent clouds, water, and snow, and values near zero represent rock and bare soil.
An NDVI is often used worldwide to monitor drought, monitor and predict agricultural production, assist in predicting hazardous fire zones, and map desert encroachment. The NDVI is preferred for global vegetation monitoring because it helps compensate for changing illumination conditions, surface slope, aspect, and other extraneous factors (Lillesand 2004).
The equation for NDVI is as follows:
NDVI = ((IR - R)/(IR + R))- IR = pixel values from the infrared band
- R = pixel values from the red band
This scientific index outputs values between -1.0 and 1.0, which represents vegetation density and vigor. Negative values are mainly generated from clouds, water, and snow, and values near zero are mainly generated from rock and bare soil. Very low values (0.1 and below) of NDVI correspond to barren areas of rock, sand, or snow. Moderate values (0.2 to 0.3) represent shrub and grassland, while high values (0.6 to 0.8) indicate temperate and tropical rainforests.
The following images are examples of a Landsat 7,4,3 band combination (the first image) and an NDVI using a color map that highlights the agricultural activity of the area (the second image): 
