id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc 3222,warp masking problems,warmerdam,warmerdam,"Frank, When warping from image ‘a’ to ’b’, gdalwarp with cutline and cblend options also draws in black values from ‘b’ along the cutline. I’m attaching sample images to illustrate the issue. So when I run something like this: {{{ gdalwarp E:\DEV\2009\Frank\cutline\p0018.tif E:\DEV\2009\Frank\cutline\R021C058_output.tif -cutline E:\DEV\2009\Frank\cutline\cutline.shp -cblend 10 }}} the black area from the existing image (R021C058_output) bleeds in along the cutline. We want to avoid this somehow to keep the resulting mosaick clean on the outer boundary of the cutline. I tried using the dstnodata option like this so that black pixels are not used in the blending: {{{ gdalwarp E:\DEV\2009\Frank\cutline\p0018.tif E:\DEV\2009\Frank\cutline\R021C058_output.tif -cutline E:\DEV\2009\Frank\cutline\cutline.shp -cblend 10 -dstnodata “0 0 0” }}} However this produces very odd output where the cutline seems to have been ignored in some areas (eastern straight edge of the cutline) and applied as a hard cutline (eastern sloping edge of the cutline) but offset from the actual cutline by the blend distance. It is difficult to explain but if you run the command above and look along the eastern edge of the cutline in the mosaic, you should be able to see this. Could you please take a look at this? Thanks, Vikalpa",defect,closed,normal,,Algorithms,unspecified,normal,fixed,warp,vjetly