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<p>Hi Micha, <br>
</p>
<p><br>
</p>
<p>I successfully run your R script. However to output is weird and
I don't know how to fix it. <br>
</p>
<p>In v.kernel, you can setup the "raduis" parameter to control what
I assume to be the size of the kernel (of the moving window). I
made one test with radius=300 and another with value 3000. The
result of the first is more what I would expect in terms of
spatial variability. <br>
</p>
<p><br>
</p>
<p>When I try your script, the output raster has a size of 128x128
which did not correspond at all to my computational region, and
thus the resolution is not the same as the one defined in the
computational region. <br>
</p>
<p><br>
</p>
<p>The other thing is that I'm wondering if it is possible to
control the size of the moving window with the "density" function
in R. I already tried the 'n' parameter but it doesn't change
anything.. <br>
</p>
<p><br>
</p>
<p>I also tried with real weights (the number of inhabitants) and a
unity weighting (value 1 for all points) to see it there is a
change and there is which proof the weights affect the output :)<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">Le 22/10/19 à 13:41, Micha Silver a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:305dc7c9-9b5d-cd22-2c1c-303dafdb15f2@gmail.com">
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<p>Here is the script.</p>
<p>Let me know how it goes. (I might try to take time to make it
into a GRASS addon)</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 10/22/19 2:33 PM, Taïs wrote:<br>
</div>
<blockquote type="cite"
cite="mid:d40a1138-065b-98f1-2f44-bf86f9a3ce7a@ulb.ac.be">
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charset=UTF-8">
<p>Hi Micha, thanks for your repply.<br>
</p>
<p><br>
</p>
<p>For my own need, I think your solution is enough and I would
like to try if you agree to send the R script. <br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">Le 22/10/19 à 12:53, Micha Silver a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:72bfdf77-6ba0-d4ad-7070-c691c0c08338@gmail.com">
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<br>
<div class="moz-cite-prefix">On 10/21/19 1:33 PM, Tais wrote:<br>
</div>
<blockquote type="cite"
cite="mid:d581c296-ec9e-b2a1-7733-45722647afa2@ulb.ac.be">Hi
all, <br>
<br>
I would like to compute a raster density map ("heat map")
from vector points using v.kernel. The points represent
house addresses. However, I would need to weight the points
with a value stored in the attribute table (number of
inhabitants). I saw on the module manual page that this
functionality is a "known issue". <br>
<br>
I imagined a solution to by-passe the limitation: duplicate
each point as many time as needed (according to the value
stored in the attribute table) and use this new layer
directly in v.kernel. However, I think it will definitely
not be the most efficient way to do the trick. Do you have
an alternative in mind ? <br>
<br>
Of course the best solution would be that someone in the
development community would have the time and the kindness
to implement this function directly in the module (I'm not
skilled in C and thus cannot try myself). <br>
<br>
</blockquote>
<p><br>
</p>
<p>Maybe not the answer you are looking for, but you can
create a weighted kernel density in R. I can send an R
script that is intended to be run from within a GRASS
session. It accepts a point vector and attrib column, and
creates a kernel density raster, weighted by the attribute
values (using the R defaults for bandwidth and Gaussian
kernel)</p>
<p>Requires, of course, that R is installed, with the
packages: spatstat, raster, rgrass7.<br>
</p>
<p><br>
</p>
<blockquote type="cite"
cite="mid:d581c296-ec9e-b2a1-7733-45722647afa2@ulb.ac.be">NB:
Sorry if I should have posted this on the developer mailing
list. I hesitated but decided to post here finally. <br>
<br>
Best, <br>
<br>
</blockquote>
<pre class="moz-signature" cols="72">--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918</pre>
</blockquote>
</blockquote>
<pre class="moz-signature" cols="72">--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918</pre>
</blockquote>
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