[GRASS-user] r.shade.relief: Results Not As Expected

[Glynn Clements]

Rich Shepard wrote:

>    Assuming the 10m resolution of the DEM was too coarse I used g.region to
> change the resolution to 1m, then ran r.resamp.interp with method=bicubic.
> This was followe by r.shade.relief. The resulting map looks like a
> basin-and-range province, with mountains running north-south in parallel.
> That's not what the basin and surrounding area looks like.

Run r.slope.aspect on the interpolated map, and check for grid-like
artifacts.

How good is the underlying data? If it's noisy, it may need to be
filtered before interpolating.

Also: which version of GRASS are you using? There was a bug in the
cubic interpolation code, but that was fixed quite a long time ago.

-- 
Glynn Clements <glynn at gclements.plus.com>