Incorrect result from Build Walls process?

Discussion created by taojing on Mar 12, 2014
HI, would anyone give me some idea about this issue? My study area is relatively flat (10-110 ft in height, with the majority ranging 600-800 ft). I followed the terrain preprocessing sequence as listed in the tutorial and ran into this issue when finishing Build Walls:
The result looks a bit doubtful to me. I expect that the result should be a rim or a wall along the edge of the input polygons, and the width of the rim is between the outer and inner walls. However, my result does not show any walls of any dicernable thickness along the edge. Its legend appears
similar to the one from Burn Stream Slope, or the reconditioned DEM, except that the values for the legend-using classified symbols have changed (which indictes that some work was actually done).  Please see the attached image. The upper part of the range has increased dramatically.
Does my processing have any flaws? Does the default value-500 for Inner WAll Height (DEM Z-unit) needs to be adjusted for the flat topo?
Thank you for any comment!