[GRASSLIST:3304] Re: how to interpolate a raster?

Miha STAUT mihastaut at hotmail.com
Thu Apr 29 08:44:41 EDT 2004

>leo.lami at katamail.com wrote:
> > I'd like to smooth or interpolate a raster but I don't know how to do 
> > 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.


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