AnsweredAssumed Answered

Is there a problem with ndvi function in ArcMap 10.2? Not getting expected results.

Question asked by yeddi18 on Jul 14, 2014
Latest reply on Dec 18, 2015 by CBenkelman-esristaff

The imagery i am using is from landsat 8. My process is:

 

  1. bring in Bands 3 and 4 (red and infrared) to data view.
  2. Then from Windows-Image Analysis,assign the bands (red 3 IR 4) in options.
  3. then highlight the two bands and execute the NDVI function (green leaf). 

 

The resulting single band is added to the table of contents.  At that point, the scale is -1 to 1, which is a typical NDVI scale.  But when I attempt to classify the pixels, the results are in the hundredths (ie, 0.02586...) with a range of only about 0.2 instead of normal readings which would be in the tenths (0.21 ,0.32 ,0.43....) with a range of 2.0 (-1.0 to 1.0). I have also done the calculation manually in raster calculator with the float expression and gotten the same results as the NDVI function.

 

Is this an issue with the Landsat tiffs?  The NDVI function?

Thanks again!

Attachments

Outcomes