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polygon overlay 2+ messages / 2 participants [nested] [flat]
* polygon overlay @ 2010-08-31 21:14 Gary Fu <gfu@sigmaspace.com> 2010-09-01 13:42 ` Re: polygon overlay Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 1 reply; 2+ messages in thread From: Gary Fu @ 2010-08-31 21:14 UTC (permalink / raw) To: pgsql-sql Hi, I don't see any overlap between the polygon and the box in the following sql. Can anyone explain why it returns 't'? select polygon(path '((0,0),(10,10),(20,10),(10,0))') && polygon(box '((16,0),(17,1))'); ?column? ---------- t (1 row) Thanks, Gary ^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: polygon overlay 2010-08-31 21:14 polygon overlay Gary Fu <gfu@sigmaspace.com> @ 2010-09-01 13:42 ` Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 2+ messages in thread From: Tom Lane @ 2010-09-01 13:42 UTC (permalink / raw) To: Gary Fu <gfu@sigmaspace.com>; +Cc: pgsql-sql Gary Fu <gfu@sigmaspace.com> writes: > I don't see any overlap between the polygon and the box in the following > sql. Can anyone explain why it returns 't'? > select polygon(path '((0,0),(10,10),(20,10),(10,0))') && polygon(box > '((16,0),(17,1))'); > ?column? > ---------- > t > (1 row) Up to 8.4 the poly_overlap function did this: * Determine if polygon A overlaps polygon B by determining if * their bounding boxes overlap. * * XXX ought to do a more correct check! I see it's been improved for 9.0 ... regards, tom lane ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2010-09-01 13:42 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2010-08-31 21:14 polygon overlay Gary Fu <gfu@sigmaspace.com> 2010-09-01 13:42 ` Tom Lane <tgl@sss.pgh.pa.us>
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