Hi folks - I need to do some Landsat processing programmetrically, as in, through a script. I need to do basica arithmetic functions on landsat individual bands (tif files). I began to go about this by using ENVI functions, ie, calling ENVI_GET_DATA, to read in the data, and then hopefully, be able to perfrom arithmentic on the pixel values. Is this possible on a tif iamge through ENVI functions? I can apparently *open* a tif file using ENVI_OPEN_DATA_FILE, but it is not clear to me I can actually *read* the pixel values in the tif file and perform basic math on the image as a whole. I know how to do this in IDL, but I wanted to use ENVI as there are other aspects of using ENVI functions in my script, and I was trying to be consistent (ie, using fids vs luns consistently). help! I've read the ENVI programming guide, and I cannot seem to find an answer as to how to do this. I've tried assuming this should work, but my script doesn't work and throws a pretty peculiar error - so I wanted to know if this was even valid to try to do. thank you, Cyndy