[postgis-users] ST_StartPoint() for MultiLineStrings

[Sandro Santilli]

I'd rather keep it as it is, or even have it throw an exception.
If you want all endpoints use ST_Boundary (which should be extended
to support boundary node rule, btw).

I was also thinking that ST_StartPoint could probably be improved
to avoid full detoasting of the geometry...

--strk;

On Thu, Sep 27, 2012 at 08:06:38AM -0700, Martin Davis wrote:
> In which case why not just extend ST_StartPoint to include this
> behaviour?  Always nicer to keep the function list as short as
> possible.
> 
> On 9/27/2012 7:31 AM, David William Bitner wrote:
> >Perhaps to match a number of people's expectations, there should
> >be an ST_First Point() that is basically
> >ST_StartPoint(ST_GeometryN(ST_Multi(geometry),1))
> >
> >
> >
> >On Tue, Sep 25, 2012 at 4:08 PM, Paul Ramsey <pramsey at opengeo.org
> ><mailto:pramsey at opengeo.org>> wrote:
> >
> >    When ST_NumGeometries == 1, you can run ST_StartPoint on
> >    ST_GeometryN(geom,1). Where ST_NumGeometries > 1 you are in
> >    "interpretation land". What's the start point of a geometry with two
> >    lines?
> >
> >    P.
> >
> >    On Tue, Sep 25, 2012 at 1:38 PM, David Quinn
> >    <daithiquinn at gmail.com <mailto:daithiquinn at gmail.com>> wrote:
> >    > As ST_StartPoint( multilinestring ) returns NULL for PostGIS 2.0
> >    > (http://postgis.refractions.net/docs/ST_StartPoint.html ), what
> >    > approach can be used to identify the start and end points of a
> >    > multilinestring?
> >    >
> >    > Thanks,
> >    > David
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> >
> >-- 
> >************************************
> >David William Bitner
> >
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