[postgis-users] Centroid Calculation Error???

[Düster Horst]

I try to calculate a centroid for a polygon with 
 
select centroid(wkb_geometry) from polygon_table;
 
You can see the result of the calculation in the attached image. The red
point is the place of the calculated centroid. This place is obviously
wrong. I think the reason for this wrong placement is the weight of the
vertex points (yellow with black center). The centroid point is shifted to
the north east edge of the polygon due to the heavy concentration of vertex
points in this area of the polygon. In my opinion the distribution of vertex
points shouldn't have an influence of the centroid position.
 
Perhaps I'm wrong?? Any hints?
 
Horst
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