Pathdistance problem

Discussion created by johnwkantner on Aug 16, 2010
Latest reply on Aug 19, 2010 by johnwkantner

I'm trying to use Pathdistance and a custom vertical factor table to create a cumulative cost-surface that represents travel time away from the source point. It works just fine with a 30-m DEM and/or a small extent, but if I try a large 10-m DEM, I get "holes" and "ridges" in the resulting cost-surface in which the accumulated cost begins to decrease as you move away from the source -- and then starts to increase again. See attached image for an example (blue point is source; note decreasing accumulated cost to west).

I've tried all kinds of trouble-shooting -- rebuilding the DEM, reprojecting it, using source from a raster, using source from a shapefile -- all to no avail. I suspect there must be computational limitations in Pathdistance??

All thoughts on this welcome!