What kind of maps should be used for Normalized Difference Vegetation Index (NDVI) analysis using GIS. Are these available in USGS ?
Hi Harisankar,
Do you mean how to create NDVI Maps? NDVI Maps can be created potentially with any satellite image which provides data in the Near Infrared and Red wavelength region of the electromagnetic spectrum. This vegetation index exploits the contrasting reflectance properties in the two wavelength bands where vegetation has distinct characteristics. As far as the data is concerned, yes you can get a number of options via USGS either in the form of NDVI products such as eMODIS NDVI, NOAA CDR NDVI based on AVHRR etc. If you want to create your own NDVI Maps, Landsat satellite data is a good starting point.
http://earthexplorer.usgs.gov/
http://earthobservatory.nasa.gov/Features/MeasuringVegetation/
I think you need high resolution SPOT imagery if possible. You also can get the NDVI data from USGS, but its resolution is not very high. Anyway, you can choose one based on your needs.
I have used Landsat TM 5 imagry 30 M for NDVI analysis using band 3 and 4 and I got good findings. In addition, you can use another type of S. Images.
Dear Harisankar
You can download Landsat 8 image from USGS. 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).
NDVI Formula:
NDVI = (NIR - red) / (NIR + red)
You can calculate NDVI from 4th and 5th bands (Landsat 8 image). Here band 4= RED and band 5=NIR.
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