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I have been trying to crop the white collar off two adjacent USGS maps and then stitch the two together. I do not want to use qGis or ArcGis. I am using gdal. I have tried via command line and the C# bindings via MaxRev. First I take the geoPDF downloaded from USGS. Then I run gdalwarp with the following options: "-te", xmin.ToString(), ymin.ToString(), xmax.ToString(), ymax.ToString(), "-t_srs", projectionWkt, "-r", "bilinear", "-dstalpha", "-of", "GTiff" Where the xmin, ymin, xmax, ymax are the coordinates of just the center map based on values in the map and the amount to cut off. projectionWkt is the source from the file. This gives me an image which is cropped. However when I stitch them together they do not line up. Does anyone have any suggestions on how I can make it line up?