<HTML dir=ltr><HEAD><TITLE>Re: [postgis-users] Buffer select from one layer to another?</TITLE>
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<DIV dir=ltr><FONT face=Arial color=#000000 size=2>Abe,</FONT></DIV>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>David's is close but doesn't use an index</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2>Try</FONT></DIV>
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<DIV dir=ltr><FONT size=2>SELECT h.* FROM houses h, </FONT><FONT size=2>roads r </FONT></DIV>
<DIV dir=ltr><FONT size=2>where r.gid=1663 and ST_DWithin(h.the_geom, r.the_geom, 500)</FONT></DIV><FONT size=2></FONT></DIV>
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<DIV dir=ltr><FONT size=2>(although the above really translates to < 500 instead of <= 500)</FONT></DIV>
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<DIV dir=ltr><FONT size=2>Hope that helps,</FONT></DIV>
<DIV dir=ltr><FONT size=2>Regina</FONT></DIV>
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<DIV dir=ltr><FONT face=Tahoma size=2><B>From:</B> postgis-users-bounces@postgis.refractions.net on behalf of David William Bitner<BR><B>Sent:</B> Wed 6/11/2008 2:08 PM<BR><B>To:</B> PostGIS Users Discussion<BR><B>Subject:</B> Re: [postgis-users] Buffer select from one layer to another?<BR></FONT><BR></DIV>
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<P><FONT size=2>Abe --<BR><BR>For this type of query, running a buffer is actually not necessary.<BR><BR>select h.* from houses h,roads r where r.name like '%MAIN%' and<BR>distance(h.the_geom,r.the_geom)<=500;<BR><BR>David<BR><BR>On Wed, Jun 11, 2008 at 12:54 PM, Abram Gillespie<BR><abe.gillespie.lists@gmail.com> wrote:<BR>> Hi All,<BR>><BR>> I'm finally starting to do some real production work ... after years<BR>> of simply using PostGIS in example scenarios as I developed zigGIS.<BR>> Pretty funny, actually. Anywho, could someone enlighten me on how to<BR>> buffer a road and return the surrounding buildings? This is what I<BR>> have so far:<BR>><BR>> select h.* from houses h,roads r where r.name like '%MAIN%' and<BR>> touches(h.the_geom, buffer(r.the_geom,500));<BR>><BR>> Now I realize the above is a bit complex since " like '%MAIN%' "<BR>> returns multiple road segments, but even working on a single road:<BR>><BR>> select h.* from houses h,roads r where r.gid=1663 and<BR>> touches(h.the_geom, buffer(r.the_geom,500));<BR>><BR>> doesn't seem to return anything. I'm positive the buffer query should<BR>> return some houses.<BR>><BR>> Thanks for any help!<BR>><BR>> -Abe<BR>> zigGIS Team<BR>> Obtuse Software, <A href="http://www.obtusesoft.com/">http://www.obtusesoft.com</A><BR>> _______________________________________________<BR>> postgis-users mailing list<BR>> postgis-users@postgis.refractions.net<BR>> <A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>><BR><BR><BR><BR>--<BR>************************************<BR>David William Bitner<BR>_______________________________________________<BR>postgis-users mailing list<BR>postgis-users@postgis.refractions.net<BR><A href="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR></FONT></P></DIV></BODY></HTML>
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