[postgis-users] View area

[Sean M. Montague]

I've investigated what the relationship of the points is to the original
poly layer, and they are not the vertices, at least not all of them.
The original layer is the coast of south east Alaska with about 25
islands.  The points may be some of the vertices perhaps, they do lie on
the coasts.  The summary() returns 556 "Object 0 is a POINT()" and 1
"Object 0 is a LINESTRING() with 2 points".  The up side is, they at
least lie within my bounding box.

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
strk at refractions.net
Sent: Tuesday, February 15, 2005 12:26 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] View area

On Tue, Feb 15, 2005 at 11:28:28AM -0700, Sean M. Montague wrote:
> For some reason this returns as SVG a bunch of points.  My whole
> statement is below.

Use summary() instead of assvg to have a readable description
of what is returned by that query.

--strk;

> 
> SELECT AsSVG(intersection(the_geom, setSRID('BOX3D(xxx yyy, xxx
> yyy)'::box3d,42102)),0,8)
> As the_geom From usa
> WHERE the_geom && setSRID('BOX3D(xxx yyy, xxx yyy)'::box3d,42102);
> 
> 
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
> strk at refractions.net
> Sent: Tuesday, February 15, 2005 10:52 AM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] View area
> 
> Intersection should do.
> Don't use GeomFromText() with anything but OGC Well Known Text format.
> 
> Try something like this:
> 
>  SELECT AsSVG(intersection(the_geom,
> setSRID('BOX3D(...)'::box3d,42102)))
>  WHERE the_geom && setSRID('BOX3D(...)'::box3d,42102);
> 
> --strk;
> 
> On Tue, Feb 15, 2005 at 10:47:32AM -0700, Sean M. Montague wrote:
> > I sent this in response to the wrong post.
> > 
> > The select statement below is close to what I'm looking for.  I
don't
> > know if I'm imagining this, but I thought it was possible to define
a
> > box and extract just what is inside that box, clipping all that lies
> > outside, including polygons.  Is this possible using a different sql
> > statement? 
> > 
> > SELECT AsSVG(the_geom,0,8) as the_geom FROM usa WHERE the_geom &&
> > GeomFromText('BOX3D(-2243528 2679134,-1689106
2002338)'::box3d,42102);
> > 
> > -----Original Message-----
> > From: postgis-users-bounces at postgis.refractions.net
> > [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
> Sean
> > M. Montague
> > Sent: Monday, February 14, 2005 5:42 PM
> > To: PostGIS Users Discussion
> > Subject: [postgis-users] View area
> > 
> > Is there a way to extract data based on viewable area coordinates.
> For
> > instance, can I extract roads that are only within my viewer area,
or
> > part of a polygon, but not the whole thing?  I've tinkered with
> > intersection, but have failed to accomplish anything.  Thanks.
> > 
> > Sean
> > _______________________________________________
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