[postgis-users] why is this poly invalid?
mbdavis at refractions.net
Tue Oct 30 09:02:29 PDT 2007
It might be nicer if it worked that way, but currently that's not the
case. The justification is:
- geometric functions are only guaranteed to return correct results on
valid input (except for isValid, of course)
- valid polygonal geometries are by definition simple
In other words, the domain of isSimple is really just linear geometry -
there's no point in calling it for polygonal geometry.
Rob Agar wrote:
> Nicolas Ribot wrote:
>> No, self-intersecting polygons are not valid in postgis.
> OK, that makes sense. But shouldn't st_issimple return false for a
> self intersecting poly?
> > Try to edit it to correct the intersection.
> I will - it's just a matter of swapping a couple of points. But I'll
> tell the Great Barrier Reef Marine Park Authority that their data's
> dodgy :)
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Senior Technical Architect
Refractions Research, Inc.
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