MODIS (Moderate Resolution Imaging Spectroradiometer) was launched by NASA aboard the Earth Observing System (EOS) satellite Terra on December 18, 1999. A second MODIS instrument was launched May 4, 2002 on the EOS-Aqua platform. With both instruments in operation, MODIS provides a morning and afternoon view with global, near-daily repeat coverage.

The MODIS single channels (MIR for middle infrared, NIR for near infrared and Red) at 250m spatial resolution, available in the data library, are retrieved from the MODIS vegetation index (VI) products MOD13Q1 which contain two indices: the Normalized Difference Vegetation Index (NDVI) and a new Enhanced Vegetation Index; VI quality information and composited surface reflectance bands including the blue (459-479nm) the red (620-670nm), the near-infrared (841-876nm) and the middle infrared (2105-2155nm). The MODIS VI algorithm operates on a per-pixel basis and relies on multiple observations over a 16-day period to generate a composited product. The goal of compositing methodologies is to select the best observation, on a per pixel basis, from all the retained filtered data, to represent each pixel over the 16-day compositing period. The MODIS VI compositing algorithm consists of three components:

bidirectional reflectance distribution function composite.
constrained-view angle - maximum value composite,
maximum value composite.
Further information on MODIS VI products can be found at: VI Algo Procedures and MODIS