[GRASS-user] v.surf.rst vs r.slope.aspect

[Pierre Roudier]

Hi Moritz,

> When you say that there are differences, which DEM did you use with
> r.slope.aspect ? The one create by the v.surf.rst run ?

Yes - for the sake of the test, I generated a DEM and slope using
v.surf.rst. Then I used r.slope.aspect on that DEM, and compared its
output with the v.surf.rst one. Indeed, the r.slope.aspect looks like
a smoother version of v.surf.rst. Sort of between the v.surf.rst
result and its 3x3 average smooting (using r.neighbors).

> v.surf.rst estimates a surface from points and then gives you the slope and
> aspect resulting directly from the approximation function. r.slope.aspect
> uses an existing DEM and calculates slope and aspects within a 3x3
> neighbourhood.

Okay, so v.surf.rst gives a sharper result? I was wondering if it was
the case... or if it was more "noisy".

Cheers,

Pierre

-- 
Scientist
Landcare Research, New Zealand