Hi, I would like to build a binary image from a range of DNs of a single band. I'm trying to isolate shadows (if it matters), I need to do a small manipulation to the mask before it is applied to the image, so I need to write the 'raw' mask to disk. I'm using the third band or Value band of the HSV image. This is my code so far, I will adapt it to batch File_Search, but for now I'm just feeding it a hard path to a test image. ; Open the HSV file file = "E:\2013img\LauraZones\processing\LZ01_1vegHSV" raster = e.OpenRaster(file) ;begin HSV manipulation block ValName = file + 'v' ;subset/threshold by DN range 0.1 to 400 in band 3 or V outMASK = file + 'drk400' ;subset HSV to only Value band Val = ENVISubsetRaster(Raster, BANDS=2) iVal = ENVIRaster(Val, URI=ValName) iVal.Save ; generate a mask MAXmask = IMAGE_THRESHOLD(Val, HISTMAX=400, /MASK_INVERT) MINmask = IMAGE_THRESHOLD(MAXmask, HISTMIN=0.1) mVal = ENVIRaster(MINmask, URI=outMASK) mVal.Save Right now the code hangs up on the line iVal = ENVIRaster(Val, URI=ValName). Seams like I don't have a firm understanding of how to pass Virtual Rasters as variables. That might be the problem :/ The last two lines of code are to give the result of the thresholding a logical name on disk, has a high likelihood of being a misstep too, but haven't gotten the code to run that far yet. Any help would be wonderful, Thank you, Laura