<div dir="ltr">Thanks for the information above, it was very helpful and i now have a better understanding of the interpolation process. <div>As a follow up question, i could not find the krigging function in the processing toolbox, only TIN and IDW. where do i look for the krigging interpolation</div><div>Also, i understand the construction of delawney triangles and veronoi diagrams now and how the veronoi cells are constructed. What i am not clear on is, once you have completed the interpolation and you have your delawney triangle boundaries, how does this get translated to at regular grid. </div><div>the triangular mesh is irregular, how does this get referred to a rectangular grid? if you have a brief description, that is adequate. </div><div><br></div></div><div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br>
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</table><a href="#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2" width="1" height="1"></a></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Dec 6, 2021 at 2:51 PM Nicolas Cadieux <<a href="mailto:njacadieux.gitlab@gmail.com">njacadieux.gitlab@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Hi,</p>
<p>Open the Processing toolbox panel, search for 'Krigging'. You
will see multiple SAGA modules. If you search for "interpolation",
you will find IDW AND TIN under Q modules and other methods under
the SAGA module. If you search for "grid" you will find multiple
algorithms under GDAL/Raster analysis. See
<a href="https://gdal.org/tutorials/gdal_grid_tut.html#gdal-grid-tut" target="_blank">https://gdal.org/tutorials/gdal_grid_tut.html#gdal-grid-tut</a> and
<a href="https://gdal.org/programs/gdal_grid.html" target="_blank">https://gdal.org/programs/gdal_grid.html</a> for other methods. This
should cover it.</p>
<p>The idea is generally to interpolate a raster surface from points
or lines containing a z field or a z value (in 3D files). After,
you use Raster/Extract/Contour on this new raster layer. You can
also install the contour plugin. That uses a point file only but
I don't know the what algorithm it uses.<br>
</p>
<p>You may find more algorithm using CrimeStat or GeoDa softwares.<br>
</p>
<p>Hope this helps.</p>
<p><br>
</p>
<p>Nicolas<br>
</p>
<p><br>
</p>
<p><br>
</p>
<div>On 2021-12-06 1:59 p.m., Firstname
Lastname wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">hello group:
<div>i want to demonstrate some of the pitfalls of computer
contouring methods with limited datasets. i wanted to use a
small dataset to demonstrate several contouring algorithms.
In particular, linear interpolation, inverse weighted, nearest
neighbour and kriging. Are any of these built into QGIS? i
do not see any options to control the contouring in the
plugins for any options other than the default. </div>
<div>thank you if you can provide any help.<br clear="all">
<div><br>
</div>
-- <br>
<div dir="ltr">
<div dir="ltr">Byron Veilleux, MSc. P.Geo
<div>Conjugate Geologic Services Limited</div>
<div>Calgary, Alberta Canada</div>
<div><a href="mailto:byron@conjugategeo.com" target="_blank">byron@conjugategeo.com</a></div>
<div>Cell:4037108414</div>
</div>
</div>
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</div>
<br>
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</blockquote>
<pre cols="72">--
Nicolas Cadieux
<a href="https://gitlab.com/njacadieux" target="_blank">https://gitlab.com/njacadieux</a></pre>
</div>
</blockquote></div>