I have a doubt related with NDVI images. How make accuracy from a NDVI difference image? How to create an error matrix with the classes "increase", "decrease" and "no change"? I created train sites in the right places but now I don't know how to create an error matrix on ENVI 4.
In Classification > Post-Classification > Confusion Matrix > Using Ground Truth ROIs, ENVI 4 tells that need a Classification Image and my NDVI difference image doesn't fill this requirement.
With GDAL this can be made too?
Thanks a lot!