Vegetation Indexes

Normalized Difference Vegetation Index (NDVI):

Normalized Difference Vegetation Index proposed by Rouse et.al. (1973), NDVI is a measure of healthy, green vegetation. The combination of its normalized difference formulation and use of the highest absorption and reflectance regions of chlorophyll make it robust over a wide range of conditions, the value of this index ranges from -1 to 1. The common range for green vegetation is 0.2 to 0.8.

Atmospherically Resistant Vegetation Index (ARVI):

Main advantages of this index is its resistance to atmospheric effects, as compared to the Normalized Difference Vegetation Index which is accomplished by a self-adjustment procedure for the atmospheric influence on the red band, using the difference in the radiance between the blue and the red bands to correct the radiance in the red band. Simulations using radiative transfer computations on arithmetic and natural surface spectra, for numerous atmospheric conditions, show that ARVI has an analogous dynamic range to the NDVI, but it is less sensitive to atmospheric effects than the NDVI [9]. The formula for ARVI for narrowband data is as given below.

ARVI: (?864 - [2 × ?671 - ?467])/(?864 + [2 × ?671 - ?467])

Red Edge Normalized Difference Vegetation Index (RENDVI):

Red Edge Normalized Difference Vegetation Index: The reflectance near 700 nm has found to be very sensitive to red edge position as well as chlorophyll concentration [10] RENDVI gives normalized value at the wavelength of 752 nm and 701nm the equation for this Index is as given in equation.

RENDVI= (p752 - p701)/(p752 + p701)

Modified Red Edge Normalized Difference Vegetation Index (MRENDVI):

This index is a modification of the Red Edge NDVI that corrects for leaf specular reflection. It capitalizes on the sensitivity of the vegetation red edge to small changes in canopy foliage content, gap fraction, and senescence. Applications include precision agriculture, forest monitoring, and vegetation stress detection.

The value of this index ranges from -1 to 1. The common range for green vegetation is 0.2 to 0.7. See Narrowband Definitions for the allowable range of wavelengths.

Normalized Difference Infrared Index (NDII):

NDII is the reflectance estimation that represents to changes in water substance of plant canopy. It is not the simple ratio index it is normalized difference index. It increases with increasing water contents in the canopy its range is -1 to 1,for green vegetation it varies from 0.02 to 0.6.