[postgis-users] Bounding Box Query

[Tyler Mitchell]

Do you have the x,y coordinate pair in a table in the database?
Do you have the road data in a table too?

postgis-users-bounces at postgis.refractions.net wrote on 03/29/2004 08:40:07 
AM:

> Hi Tyler,
> This is the first time I am getting a response from member listers.
> Thanks for inquiring.,
> Can you repost your response, please?
> 
> 
> >From: Tyler Mitchell <TMitchell at lignum.com>
> >Reply-To: PostGIS Users Discussion 
<postgis-users at postgis.refractions.net>
> >To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> >CC: 
> >postgis-users at postgis.refractions.net,postgis-users-
> bounces at postgis.refractions.net
> >Subject: Re: [postgis-users] Bounding Box Query
> >Date: Mon, 29 Mar 2004 08:36:30 -0800
> >
> >Are you getting email from the list okay?  A couple of us had responded 
a
> >week or so ago...
> >
> >postgis-users-bounces at postgis.refractions.net wrote on 03/29/2004 
05:51:08
> >AM:
> >
> > > I had posted this question here before but didn't get any response.
> > > I was encouraged to try it again.
> > >
> > > I have a query that retrieves an address closest to a point given an 
x/y
> >
> > > coordinate pair.
> > >
> > > This is that query:
> > >
> > > SELECT str_num || ' ' || name as full_address,
> > >    distance(the_geom,'POINT(2227284.1963667543
> > > 1435389.6730164126)'::geometry) as dist
> > >    FROM address
> > > ORDER BY dist limit 1
> > >
> > > The above query works as far as returning the closest address to a 
point
> >
> > > based on x/y coordinate pair.
> > >
> > > Hower, performance is really bad as it takes quite sometime for this
> >query
> > > to retrieve a record.
> > >
> > > I have a about bounding boxes or overlap operator (&&) as a means of
> > > improving performance.
> > >
> > > I don't quite understand it how works.
> > > For instance, given the below query (which doesn't work by the way),
> > >
> > > SELECT str_num || ' ' || name as full_address,
> > >    distance(the_geom,'POINT(2227284.1963667543
> > > 1435389.6730164126)'::geometry) as dist
> > >    FROM address
> > >    WHERE the_geom && 'BOX3D(90900 190900, 100100 200100)'::box3d
> > >    AND distance( the_geom( 'POINT(2227284.1963667543
> >1435389.6730164126)',
> > > -1 ) ) < 100
> > > ORDER BY dist limit 1
> > >
> > > My questions are:
> > > 1, how are the arguments in bo3d shown below generated? I just 
filled in
> >
> > > those numbers without knowing where they come from or how they are
> > > generated.
> > >
> > >    WHERE the_geom && 'BOX3D(90900 190900, 100100 200100)'::box3d
> > >    AND distance( the_geom( 'POINT(2227284.1963667543
> >1435389.6730164126)',
> > > -1 ) ) < 100
> > >
> > > 2, how can I apply the information on question 1 to with the query 
above
> >
> > > (the one indicated as a working code)?
> > >
> > > All research I have done so far have not helped me.
> > > Your assistance is greatly appreciated.
> > >
> > > _________________________________________________________________
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