A few weeks ago I posted a message requesting help with a problem I was having
with r.slope.aspect. When I used this command on a dem the resulting maps
came out with linear areas of 0 slope in areas that should have contained
relatively steep slopes. We'll, I think I found a solution (or at least a
fudge).I did a reclass of all the areas that had 0 slope and turned them into
areas of "no data." I then used r.surf.idw2 to interpolate the values for all
the areas of no data. The resulting map seems much better than the original
(although it is not perfect). Does anyone know if I violated any cardinal
rules by doing this? If so, any other solutions?Bill Green
wg1938@cnsunix.albany.edu
Hi Bill,
You've hit upon a solution similar to the one I've used for a bad DEM.
However, if you do this on the Slope layer instead of on the DEM itself, I
think you are introducing errors. Try turning the DEM to 'no data' where
the Slope = 0, then re-interpolating the DEM and recalculating Slope from
that, and see if you end up with a better slope map. Of course, this
isn't going to be perfect either...
Martijn
P. Martijn van Leusen -------------------------------------------------------+
Leverhulme Research Fellow, The Wroxeter Hinterland Project |
University of Birmingham Field Archaeology Unit |
Edgbaston, Birmingham B15 2TT |
Phone +44 121 414 5513 Fax +44 121 414 5516 E-mail P.M.van-Leusen@bham.ac.uk