[GRASSLIST:1040] Re: interpolation from vector points

[David Finlayson]

Here's an automated way:

v.hull input=points output=point_hull
v.to.rast input=point_hull output=point_mask use=val value=1
r.mapcalc "interp_trim = if( isnull( point_mask), null(), interp_values)"

where interp_values is the raster interpolation of your points.

You may find that v.hull doesn't do a good enough job of outlining
your data points. In that case, you will need to edit the vector
created by v.hull to something you like better.

Hope that helps,

David

On 5/8/06, Luca Penasa <luca.penasa at email.it> wrote:
> Iv a mapset with a lot (200) of point. Every point is a pollution
> indicator (a tree, a bush...) with many informations, one of these is a
> lichens biodiversity index.
> What i want to do is to interpolate this index value to obtain a map of
> biodiversity of the city covered by the survey.
> Iv done the interpolation (with no so good results) but now i need to
> cut the raster obtained around the external points... maybe i have to do
> something like a buffer around the external points of survey and cut the
> map obtained from interpolation. How can i do that without have 'holes'
> in the internal part of the map? is there a way to do that?
>
>
> Sorry for my English
>
> Luca
>
>
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--
David Finlayson