| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> |
| Cc: | Colin Dunklau <colin(dot)dunklau(at)gmail(dot)com>, pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: postgres 9.2.2 point conversion from polygon doesn't always give accurate center |
| Date: | 2013-02-03 16:02:26 |
| Message-ID: | 7650.1359907346@sss.pgh.pa.us |
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| Lists: | pgsql-bugs |
Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> writes:
>>> It looks like what the code is actually computing is the average X
>>> position and average Y position of the points listed in the polygon.
> Although, if that's really how it's being calculated, then that's not
> really the centroid.
Yeah --- according to the wikipedia entry, it's the correct answer if
we consider the polygon vertexes as a disconnected collection of points
... but that's probably not what people really expect. I think a
"correct" answer in full generality for polygons that are non-convex,
contain duplicate points, etc might be pretty hard.
regards, tom lane
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