GRASS users,
I created a surface map with r.surf.idw which appears to contain good data (thanks to Melissa Records for helping me get this far). This surface map was created at a resolution of 0.5m (which I think is justified because my original elevation data, which I would like to preserve, contains 1' contour intervals). The optional parameter npoints was left at the default value of 12.
The Problem:
From this surface map , I would like to create a slope map. I used r.slope.aspect but got a map that looked like the contour line map which I started with. There were medium thick "lines" of steep slopes (mostly 15-20%) surrounded by large flat (percent slope = 0 or "no data") areas. In other words, I got a really stair-stepped appearance rather than nice steady slopes.
I tried decreasing the resolution of the surface map (to res=1m) and/or increasing the number of nearest data points (npoints), but to no avail. Any ideas?
Matt Knox
Fort Lewis (WA) Environmental & Natural Resources Division