Rahul, very interesting question..

NDVI Definition: NDVI is an index describing vegetation by showing the difference between near-infrared (which is strongly reflected by vegetation) and red light (which is absorbed by vegetation). You can create NDVI maps with the image analysis toolbar in ArcGIS 10. All you need is imagery with red and NIR bands. Examples are Landsat, Quickbird and Worldview-2.NDVI maps use NIR and red channels to measure of healthy vegetation.

Mapping vegetation through remotely sensed images involves various

considerations, processes and techniques. Increasing availabilityof remotely sensed images due to the rapid advancement of remote sensing technology expands the horizon of our choices of imagery sources. Various sources of imagery are known for their differences in spectral, spatial, radioactive and temporal characteristics and thus are suitable for different purposes of vegetation mapping. Generally, it needs to develop a vegetation classification at first for classifying and mapping vegetation cover from remote sensed images either at a community level or species level. Then, correlations of the vegetation types (communities or species) within this classification system with discernible spectral characteristics of remote sensed imagery have to be identified. These spectral classes of the imagery are finally translated into the vegetation types in the image interpretation process, which is also called image processing. This paper presents an overview of how to use remote sensing imagery to classify and map vegetationcover. Source ; Journal of Plant Ecology, VOLUME 1, NUMBER 1,PAGES 9–23

doi: 10.1093/jpe/rtm005..

Hope , you find it useful...

@Anoop sir,

Thank you for the valuable response. I just saw the journal you suggested. It is really helpful.