Example of filtering process applied to significant elevation diff

Example of the results of the filtering process applied to significant elevation differences. From left to right, the images are NED shaded relief, SRTM shaded relief, SRTM NED difference grid (blue = significant decrease in elevation; red = significant increase in elevation), and polygons outlining areas of significant topographic change overlaid on SRTM shaded relief (yellow = polygons remaining after filter process; orange = polygons eliminated by filter process). The area shown is in West Virginia and is about 3.7 km east-west by 6.9 km north-south.

More information can be found on the Significant Topographic Changes in the United States website.