[postgis-users] Density calculation

[Uli Mueller]

Hi

I am trying to calculate a density surface from points in a postgis
database. The result should be stored in a new table in PostGIS and should
display in MapServer. Any ideas about a fast way to do this in a
PostGIS/PHP/MapScript-environment?

I would prefer to do the whole calculation directly within SQL (for matters
of speed and reusability in different projects). I have been experimenting
with creating a temporary pivot table representing a matrix of all x- and
y-coordinates of my study area. Then I calculate the number of points within
a given radius from each matrix cell. Principally, this approach works, but
of course it tends to be very slow. I would appreciate to know about a
better solution.

Uli
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