[postgis-users] Midpoint function?

[Rodrigo Martín LÓPEZ GREGORIO]

Hi Pradeep

I don't know what you exactly mean by midpoint of a MULTILINESTRING. If what
you are looking for is the point on the multilinestring located half way on
a imaginary linestring that have the total length of the MULTILINESTRING and
is formed by sewing together constituent linestrings I can write a function
that do this. Must it fill the gaps between end point of first linestring
and start point of second linestring (i.e. consider the space between
consecutive linestrings as part of this imaginary linestring)? If you have
any other detail about the function you want tell me.

Rodrigo.

On 6/21/07, Pradeep B V <pradeepbv at gmail.com> wrote:
>
> Is there any other function equivalent to the line_interpolate_point(the_geom,
> 0.5) to find the midpoint of a MULTILINESTRING?
>
> the line_interpolate_point works only with LINESTRINGS.
>
> - Pradeep B V
> www.btis.in
>
>
> On 6/21/07, Rodrigo Martín LÓPEZ GREGORIO <rodrigomartin at lopezgregorio.com.ar>
> wrote:
> >
> > Hi Matt.
> >
> > I think what you want may be:
> >
> > line_interpolate_point(the_geom,0.5)
> >
> > (or ST_line_interpolate_point(the_geom,0.5) depending on your Postgis
> > version)
> >
> > where the_geom is a linestring and 0.5 means half of the total 2d length
> > of the linestring.
> >
> > You can reed more details in the documentation:
> >
> > http://postgis.refractions.net/docs/ch06.html#line_interpolate_point
> >
> > Rodrigo
> >
> > On 6/21/07, Matt Doughty < matt.doughty at geograma.com> wrote:
> > >
> > >  Hi List,
> > >
> > >
> > >
> > > Is there a function in PostGIS that finds the midpoint of a line?
> > >
> > >
> > >
> > > Matt
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Matt Doughty
> > >
> > >   GEOGRAM A S.L.
> > >
> > > Tel.:  +34 945 13 13 72    652 77 14 15
> > >
> > > Fax: +34 945 23 03 40
> > >
> > > www.geograma.com
> > >
> > >
> > >
> > >
> > >
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> >
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