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List: postgis-users
Subject: Re: [postgis-users] st_intersects() returns false with point
From: Arnold Helmut Engelmann <ahe () dhi ! us>
Date: 2011-02-24 0:32:25
Message-ID: AC8CAB962DA65D419B5F4A74EFA670194030C09D () PDXMAIL ! dhi ! us
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Perhaps it's a precision issue? If you parse these into a single precision floating \
point number, they are equal (all the longitude values anyway-the latitude is only \
equal on one boundary). Not sure if this would be a PostGIS or PostgreSQL problem.
Arnold
From: postgis-users-bounces@postgis.refractions.net \
[mailto:postgis-users-bounces@postgis.refractions.net] On Behalf Of \
Craig de Stigter
Sent: Wednesday, February 23, 2011 15:58
To: postgis-users@postgis.refractions.net
Subject: [postgis-users] st_intersects() returns false with point and polygon that \
obviously intersect
Hi list
This query returns false, but the box and point intersect:
select st_intersects('POINT(169.69960846592 -46.5061209281002)'::geometry, \
'POLYGON((169.699607857174 -46.5061218662,169.699607857174 \
-46.5061195965597,169.699608806526 -46.5061195965597,169.699608806526 \
-46.5061218662,169.699607857174 -46.5061218662))'::geometry); st_intersects
---------------
f
(1 row)
Tested on postgis 1.5.2. postgis_version(): 1.5 USE_GEOS=1 USE_PROJ=1 USE_STATS=1
Using geos via python it works:
> > > from django.contrib.gis import geos
> > > p = geos.GEOSGeometry('POLYGON((169.699607857174 \
> > > -46.5061218662,169.699607857174 -46.5061195965597,169.699608806526 \
> > > -46.5061195965597,169.699608806526 -46.5061218662,169.699607857174 \
> > > -46.5061218662))') pt = geos.GEOSGeometry('POINT(169.69960846592 \
> > > -46.5061209281002)') pt.intersects(p)
True
Any ideas? Thanks
Craig de Stigter
--
Koordinates Ltd
PO Box 1604, Shortland St, Auckland, New Zealand
Phone +64-9-966 0433 Fax +64-9-969 0045
Web http://www.koordinates.com
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class=WordSection1><p class=MsoNormal><span \
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Perhaps \
it’s a precision issue? If you parse these into a single precision floating \
point number, they are equal (all the longitude values anyway—the latitude is \
only equal on one boundary). Not sure if this would be a PostGIS or PostgreSQL \
problem.<o:p></o:p></span></p><p class=MsoNormal><span \
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p \
class=MsoNormal><span \
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Arnold<o:p></o:p></span></p><p \
class=MsoNormal><span \
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p \
class=MsoNormal><b><span \
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span \
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> \
postgis-users-bounces@postgis.refractions.net \
[mailto:postgis-users-bounces@postgis.refractions.net] <b>On Behalf Of </b>Craig de \
Stigter<br><b>Sent:</b> Wednesday, February 23, 2011 15:58<br><b>To:</b> \
postgis-users@postgis.refractions.net<br><b>Subject:</b> [postgis-users] \
st_intersects() returns false with point and polygon that obviously \
intersect<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p \
class=MsoNormal>Hi list<o:p></o:p></p><div><p \
class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>This query returns \
false, but the box and point intersect:<o:p></o:p></p></div><div><p \
class=MsoNormal><o:p> </o:p></p></div><div><blockquote \
style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in \
6.0pt;margin-left:4.8pt;margin-right:0in'><p class=MsoNormal><span \
style='font-family:"Courier New"'>select st_intersects('POINT(169.69960846592 \
-46.5061209281002)'::geometry, 'POLYGON((169.699607857174 \
-46.5061218662,169.699607857174 -46.5061195965597,169.699608806526 \
-46.5061195965597,169.699608806526 -46.5061218662,169.699607857174 \
-46.5061218662))'::geometry);<br> st_intersects <br>---------------<br> f<br>(1 \
row)</span><o:p></o:p></p></blockquote><div><p \
class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Tested on postgis \
1.5.2. postgis_version(): 1.5 USE_GEOS=1 USE_PROJ=1 \
USE_STATS=1<o:p></o:p></p></div><div><p \
class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Using geos via \
python it works:<o:p></o:p></p></div><div><p \
class=MsoNormal><o:p> </o:p></p></div><div><blockquote \
style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in \
6.0pt;margin-left:4.8pt;margin-right:0in'><p class=MsoNormal><span \
style='font-family:"Courier New"'>>>> from django.contrib.gis import \
geos<br>>>> p = geos.GEOSGeometry('POLYGON((169.699607857174 \
-46.5061218662,169.699607857174 -46.5061195965597,169.699608806526 \
-46.5061195965597,169.699608806526 -46.5061218662,169.699607857174 \
-46.5061218662))')<br>>>> pt = geos.GEOSGeometry('POINT(169.69960846592 \
-46.5061209281002)')<br>>>> \
pt.intersects(p)<br>True</span><o:p></o:p></p></blockquote></div><div><p \
class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Any ideas? \
Thanks<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p \
class=MsoNormal>Craig de Stigter<o:p></o:p></p></div><div><p \
class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>-- <br>Koordinates \
Ltd<br>PO Box 1604, Shortland St, Auckland, New Zealand<br>Phone +64-9-966 0433 Fax \
+64-9-969 0045<br>Web <a \
href="http://www.koordinates.com">http://www.koordinates.com</a><o:p></o:p></p></div></div></body></html>
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