[postgis-users] Computing a centroid on GEOGRAPHY objects

[Ed Linde]

So does this mean that if the set of points span across 2 UTM zones, then
its not possible to compute their centroid location?
The ST_Buffer does say that it won't work if the points are across multiple
UTM zones.


On Thu, Dec 6, 2012 at 11:05 PM, Paul Ramsey <pramsey at opengeo.org> wrote:

> If the points of the features are truly spread out across the world,
> the centroid is pretty meaningless. If the points of any given feature
> are relatively compact, then using an approach with _ST_BestSRID would
> work (see the def'n of ST_Buffer(Geography) for an example).
>
> P.
>
> On Thu, Dec 6, 2012 at 1:55 PM, Sandro Santilli <strk at keybit.net> wrote:
> > On Thu, Dec 06, 2012 at 09:34:53PM +0100, Ed Linde wrote:
> >
> >> I know there is a centroid computation function in Postgis, but it
> seems to
> >> only work on a geometry type.
> >> The lat/long coordinates are spread all across the globe and hence I
> cannot
> >> convert it to local UTM formats because there is a discrepancy when
> going
> >> across different zones!
> >
> > I wonder how the centroid of points spread across the globe would look
> like.
> > Jules ?
> >
> > --strk;
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