Hi there, I have a few Landsat images (ETM+ and TM) which I want to use for landcover classifications. At the moment, I am trying to atmospherically correct them using the FLAASH module, but I have a few questions about the process. Firstly, a couple of my images have some thick white clouds (not a lot, and not in my area of interest) - will these affect the outcome of the atmospheric correction, and should I try to mask them or remove them prior to carrying out the atmospheric correction in FLAASH? I have noticed that the corrected images differ between those which have cloud and those which haven’t even though they are from similar time periods, so I wonder if it has something to do with the presence of clouds. Alternatively, should I clip the image to a smaller area of interest, which would get rid of many of these clouds from the image before I do my atmospheric correction? As a related question, I have seen in the guidance that FLAASH should provide a “cloud map” output file, but this has not been produced by FLAASH when I have run it on my images – does this depend on a specific setting within the FLAASH module? When I have previously carried out atmospheric correction of Landsat images using the ATCOR module, it did a good job removing light cloud/haze from my images, but the FLAASH module doesn’t seem to be getting rid of this at all, so I wonder if I am making some sort of error. Any advice would be much appreciated! Thanks. Nicola