Good example in GDAL/Python: http://www.gis.usu.edu/~chrisg/python/2009/lectures/ospy_slides5.pdf Script for GDAL: http://www.jeremymsmith.us/davidson/NDVI.py Remember, NDVI is: *Infrared - Visible / Infrared + Visible* ##GDAL commands## Splice out a single band and save as independent geotiff: gdal_translate -of GTiff -b 2 morflex-freeflight-geo.tif morflex-freeflight-green.tif On using NDVI.py, I got this error: nautilus-2:morflex-lima-freeflight warren$ python NDVI.py Traceback (most recent call last): File "NDVI.py", line 31, in var1 = subtract(band4, band3) ValueError: shape mismatch: objects cannot be broadcast to a single shape Perhaps we can use this GDAL crop script to make both images the same shape: http://www.enricozini.org/2010/tips/gdal-crop/