[Qgis-user] how to interpolate points to a grid

[Alister Hood]

Hi,
Actually, I think the Raster Grid interpolation _is_ the correct tool, although there are other options as has been mentioned.  It is also faster and more robust than the interpolation plugin, although that may be able to produce better results (I don't know).

Alister

> Date: Fri, 5 Aug 2011 17:11:50 +0100
> From: Alexandre Neto <senhor.neto at gmail.com>
> Subject: Re: [Qgis-user] how to interpolate points to a grid
> To: "M.E.Dodd" <m.e.dodd at open.ac.uk>
> Cc: "qgis-user at lists.osgeo.org" <qgis-user at lists.osgeo.org>
> Message-ID:
>	<CA+H0G_F0wsy_Mmz+KvLD5K8z4FBFgeQZ9R_0y0GccO=vL-PHMg at mail.gmail.com>
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>
> I don't think Raster Grid Interpolation and Polygonize are the correct tools
> for what you pretend.
>
> Did you try the Interpolation Plugin? Make it active in the plugin manager,
> then check this tutorial:
> http://www.gistutor.com/quantum-gis/20-intermediate-quantum-gis-tutorials/51-inverse-distance-weighting-idw-interpolation-using-qgis.html
>
> Best Luck,
>
> Alex
>
> On Fri, Aug 5, 2011 at 2:52 PM, M.E.Dodd <m.e.dodd at open.ac.uk> wrote:
>
>>  I have various layers of points from various shapes of sampling (not a
>> regular rectangular grid) and want to interpolate each of them to produce a
>> set of raster images.  In previous GIS I have used this was generally a
>> matter of making a boundary then telling the gis the points layer and extent
>> as shown by the boundary and then trying various interpolation methods to
>> see which one looked most like the real data.  However I have yet to find
>> suitable tools in Qgis to do this.  The raster grid interpolate and
>> polygonise don't seem to have suitable options and when I did try them the
>> output looked rather strange and not what I was expecting as it seemed to
>> have missed out much of the data.
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