[postgis-users] Multi centroids

Mike Toews mwtoews at sfu.ca
Fri Dec 5 13:54:39 PST 2008


Hi,

Is there a simple way to extract the multiple centroids as MULTIPOINT 
geometries from MULTI* objects (i.e., ST_MULTICENTROID(geometry) )? The 
ST_CENTROID function only returns POINT geometries.

(An example application of this is to initially place CAD labels for 
MULTIPOLYGON features, since it appears that AutoCAD is not smart enough 
to place these properly, and need manual adjustment to avoid label 
conflicts. I have always been baffled by the purpose of multipoints 
until now.)

I'm guessing this isn't a built-in function and the solution will be a 
custom SQL or PL/pgSQL function. Thanks for any help/ideas.

-Mike




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