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Dear Idrisians,
I have a situation here. I determined changes between 1990-1995 in NDVI for
a forest area in Australia from Landsat 5 imageries. Got following results
in terms of area (cells) falling in the range of NDVI Values.
Area
Range of NDVI 1990 1995
1 -1.0 to -0.8 0 0
2 -0.8 to -0.6 0 0
3 -0.6 to -0.4 1.4 0
4 -0.4 to -0.2 46.9 0
5 -0.2 to 0 36.5 80.5
6 0 to 0.2 12.1 19.3
7 0.2 to 0.4 3.1 0.2
8 0.4 to 0.6 0 0
9 0.6 to 0.8 0 0
10 0.8 to 1.0 0 0
My question is why forested area is showing negative NDVI while such a
value usually indicates water bodies? The imageries are of Feb and March
when it is just after summer in Australia. Could seasonal vaiation be so
profound as to produce such NDVI values? There is not much in the list
archives on this point?
Any sugestions / readings would be greatly appreciated.
Thanks.
Vivek
Vivek K.Varma
Department of Forestry
Institute of Land and Food Resources
University of Melbourne, Vic. 3010
Australia
Phone: +(61) 3 8344 5238 (Work); +(61) 3 9383 3417 (Home)
FAX: +(61) 3 9349 4172
Web site: http://www.GeoCities.com/RainForest/Vines/5953/index.htm
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