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

Glynn Clements glynn at gclements.plus.com
Mon Jan 4 20:05:18 EST 2010

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

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>

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