On 10/21/19 1:33 PM, Tais wrote:
Hi all,
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".
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 ?
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).
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)
Requires, of course, that R is installed, with the packages:
spatstat, raster, rgrass7.
NB:
Sorry if I should have posted this on the developer mailing list.
I hesitated but decided to post here finally.
Best,
--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
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