[GRASSLIST:3319] Re: how to interpolate a raster?

[mahoneyd at unbc.ca]

On Thu, 29 Apr 2004, Miha STAUT wrote:

> >leo.lami at katamail.com wrote:
> >
> > > I'd like to smooth or interpolate a raster but I don't know how to do
> >it.
> > > I tried with r.surf.idw but the result is not good for me.
> > > Are there other metods more flexible?
> >
> >One alternative is to convert the raster to a sites file with
> >r.to.sites then use s.surf.rst.
> >
> >--
> >Glynn Clements <glynn.clements at virgin.net>
>
>
> Would you like to smooth an already done raster which is not very smooth
> without changing the resolution or with changing the resolution or would you
> like to interpolate a set of point (sites) data to get an estimation of the
> values between them?
>
> In the first case you can use r.mfilter or r.mapcalc's neighborhood
> modifier. As far as I know r.mfilter does not handle floating point values.
>
> In the second and third case just follow Glynn's suggestion. Or for a more
> in depth analysis you can use Gstat or R's geostatistic and spatial
> interpolation packages.
>
> Miha
>
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r.neigbors worked for me (the tension was set too high on my DEM, creating
'waves' from the contour lines).

Dave