[postgis-users] Optimization - point density calculation

Markus Schaber schabi at logix-tt.com
Wed May 28 06:04:31 PDT 2008

Hi, Paul,

"Paul Ramsey" <pramsey at cleverelephant.ca> wrote:

> (a) The ST_Transform() function is making your spatial index
> un-usable, because your spatial index is against the raw coordinates
> of your data.
> [...]
> So, first transform your data to your working projection.

You could also try to create a functional index on the transformed
geometries. In theory it should work, but I did never test it myself.


Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf.     | Software Development GIS

Fight against software patents in Europe! www.ffii.org

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