Dean Rasheed <dean.a.rasheed@gmail.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