Changes in NDVI values in Amazonia:
October 2000 through May 2001.
Notice the NDVI oscillations around Lake Titicaca in the
lower left corner, on the border between Peru and Bolivia
NDVI, short for Normalized Difference Vegetation Index, is a rough measurement of the amount of vegetation present on
the surface of the earth. NDVI is calculated by ratioing satellite observations in the Near Infra-Red and Visible
spectrums. Many current Earth science models utilize NDVI as their core land surface data set.
Generally speaking the lower the NDVI value, the less vegetation there is on the surface. Values below 0.1 are
indicative of bare soil or snow while higher values, 0.6 to 0.8 and above, indicate forests. In the animation above, the
deep purple and blue colors are tropical rainforest while the browns indicate dry soil.