I have downloaded NDVI from MODIS website and pixel values go up to -3000 to 1. I want to remove all values below -1. How do I do this?

I am using ENVI 4.3

  • 2
    Do you want to remove them visually? (i.e. ENVI will not show those values) Or do you want to remove them in the data? It's most likely that the -3000 are placeholder values for Null data, thus it would be inappropriate to reclassify them to 0. – dmahr Jun 7 '12 at 14:13
  • I want to remove them from the data. I am interested in getting the mean NDVI and -3000 significantly distorts my data. Thanks. – user2543 Jun 8 '12 at 2:36

You could build a mask from your NDVI layer by using the -3000 as your mask value in the Build Mask dialog and then either apply the mask, or just use the resulting binary mask in whatever operation you're doing.
Beware, if you apply the mask and set all those values to 0, and then get your mean, they will still affect your average, like @dmahr is saying.

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