Re: Bad behaviour on some geometric operations on degenerate polygons

On Sat, Feb 15, 2014 at 12:00:09AM -0500, Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > What is odd however, is that we allow _explicit_ creation of zero-radius
> > circles:
>
> > test=> SELECT circle '<(1,1),0>';
> > circle
> > -----------
> > <(1,1),0>
> > (1 row)
>
> > so why do we prevent the conversion of single-point polygons to circles
> > with zero radius? I don't know.
>
> Maybe we should rethink that. What you've done here seems like a kluge.

Yes, it would be much easier to allow the zero-radius circles. The
attached smaller patch allows all the cases to work:

test=> SELECT @@ polygon '((1, 1))';
?column?
----------
(1,1)
(1 row)

test=> SELECT point(polygon '((1, 1))');
point
-------
(1,1)
(1 row)

test=> SELECT circle(polygon '((1, 1))');
circle
-----------
<(1,1),0>
(1 row)

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ Everyone has their own god. +