Highlighting ridges with 250ft buffer (on 2.5ft DEM) with just ImageMagick: convert lscape_posit.png -median 100 median100.png composite -compose difference lscape_posit.png median100.png difference_median100.png Input: Output: BTW, median calculations of this size are slow, even in ImageMagick. Continue reading Landscape Position Continued– Median and ImageMagick