MODIS+Help

MODIS Data Download MODIS Sinusoidal Grid MODIS Bands

=Vegetation Indices: = This comes from Bilko Tutorial 10: A vegetation index is a quantitative measure that is related to biomass or vegetative vigour. It is usually formed from combinations of two or three spectral bands (with red and near-infrared being most common), whose values are added, divided, or multiplied in order to yield a single value (index) that indicates the amount of vigour of vegetation. Many natural surfaces are about equally as bright in the red and near-infrared part of the spectrum with the notable exception of green vegetation. Red light is strongly absorbed by photosynthetic pigments (such as chlorophyll a) found in green leaves, whereas near-infrared light either passes through or is reflected by live leaf tissues, regardless of their color. This means that areas of bare soil having little or no green plan material will appear similar in both the red and near-infrared wavelengths, whereas areas with much green vegetation will be very bright in the near-infrared but relatively dark in the red part of the spectrum. Thus, the simplest form of vegetation index is a ratio between near-infrared and ref reflectance (see the Ratio Vegetation Index below). For healthy living vegetation, this ratio will be high due to the inverse relationship between vegetation brightness in the red and near-infrared regions of the spectrum.

Here are some links that may help if you are trying to learn more about vegetation indices:
[|NDVI & EVI] [|Old but very useful information on vegetation indices by Terrill Ray]