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On Fri, 2011-08-05 at 14:52 +0100, M.E.Dodd wrote:
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<FONT SIZE="2">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.</FONT>
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Did you have a look at the GRASS plugin with it's various v.surf.* modules? That's what I usually use to interpolate i.e. an DEM grid from point elevations.<BR>
The v.surf.rst module does best when the surface should be smoothed, and not necessarily go exactly thru each point.<BR>
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