[GRASS-user] Display of Terrain Perameter Maps

Glynn Clements glynn at gclements.plus.com
Tue Mar 2 11:40:47 EST 2010


Rich Shepard wrote:

>    The output maps from r.slope.aspect. r.resamp.rst, and even r.topidx the
> output maps have values for each cell rather than trends. This is very
> difficult to interpret by non-technical viewers.
> 
>    I've seen maps of slopes, profile and planar curvature, and topographic
> wetness indices that are more smoothly colored. If one wants to determine
> the curvature of slopes adjacent to a specific cell at its base it would be
> easier to see this if the values do not change with each cell. When we stand
> at the foot of a hill we tend to not focus on each detail of the terrain but
> the overall slope, profile curvature, and planar curvature. It's this type
> of overview that I'm trying to display.
> 
>    Is there a way to get smoother output maps that are visually more
> informative to non-specialists?

Filter the input data with r.neighbors[1], r.mfilter, etc.

[1] I wouldn't use method=mode if you're going to calculate
derivatives. I'm not so sure about method=median either.

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


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