[postgis-users] adding additional points to multipoint

Markus Schaber schabi at logix-tt.com
Fri Mar 31 00:51:42 PST 2006

Hi, Christo,

Christo Du Preez wrote:

> How do I add an additional point to a multipoint geometry in an update
> statement?

select asText(geomunion('MULTIPOINT(1 1,3 3)','POINT(2 2)'));

 MULTIPOINT(1 1,2 2,3 3)
(1 row)

So you can
  UPDATE geocolumn = geomunion(geocolumn,'YOURPOINT') WHERE condition;

However, note that you don't have any influence on the ordering of the
points in the resulting multipoint, it depends on the internal geometry
indexing in geomunion.

Strk, maybe we should allow addpoint() to work with multipoints, too?

Or as alternative, add an "addgeom(collection, geometry)" that adds a
geometry to a MULTI*/GeometryCollection?


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

Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org

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