[postgis-users] Buffer select from one layer to another?

[Obe, Regina]

Abe,
David's is close but doesn't use an index
Try
 
 
SELECT  h.* FROM  houses h, roads r 
where r.gid=1663 and  ST_DWithin(h.the_geom, r.the_geom, 500)
 
 
(although the above really translates to < 500 instead of <= 500)
 
Hope that helps,
Regina

________________________________

From: postgis-users-bounces at postgis.refractions.net on behalf of David William Bitner
Sent: Wed 6/11/2008 2:08 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] Buffer select from one layer to another?



Abe --

For this type of query, running a buffer is actually not necessary.

select h.* from houses h,roads r where r.name like '%MAIN%' and
distance(h.the_geom,r.the_geom)<=500;

David

On Wed, Jun 11, 2008 at 12:54 PM, Abram Gillespie
<abe.gillespie.lists at gmail.com> wrote:
> Hi All,
>
> I'm finally starting to do some real production work ... after years
> of simply using PostGIS in example scenarios as I developed zigGIS.
> Pretty funny, actually.  Anywho, could someone enlighten me on how to
> buffer a road and return the surrounding buildings?  This is what I
> have so far:
>
> select h.* from houses h,roads r where r.name like '%MAIN%' and
> touches(h.the_geom, buffer(r.the_geom,500));
>
> Now I realize the above is a bit complex since " like '%MAIN%' "
> returns multiple road segments, but even working on a single road:
>
> select h.* from houses h,roads r where r.gid=1663 and
> touches(h.the_geom, buffer(r.the_geom,500));
>
> doesn't seem to return anything.  I'm positive the buffer query should
> return some houses.
>
> Thanks for any help!
>
> -Abe
> zigGIS Team
> Obtuse Software, http://www.obtusesoft.com <http://www.obtusesoft.com/> 
> _______________________________________________
> postgis-users mailing list
> postgis-users at postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>



--
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David William Bitner
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