# Antwort: Re: [postgis-users] Nearest point on an linestring

Christoph Spoerri cspoerri at cavtel.net
Tue Dec 21 18:41:04 PST 2004

```I have some functions that may do what you are looking for. They are not very
mature yet, but I might be able to send them to you sometimes next week.

Christoph

On Tuesday 21 December 2004 10:03, skoehler at buschjena.de wrote:
>
> but I search for an new point on a linestring.
>
> *L1
>
>
> x        *P1
>
>
> *
> In this example I search the coordinates for point x. The * are the points
>
> from the linestring and the point.
> Any idea?
>
> bye
> Steffen
>
> postgis-users-bounces at postgis.refractions.net schrieb am 21.12.2004
>
> 09:53:09:
> > create a plp/pgsql function using numpoints() and pointn() and find the
> > minimum distance for each point from the linestring to your query
>
> point...
>
> > numpoints() help you to know the number of points in the lienstring and
> > pointn() extract the n° point of the lienstring
> > ----------------------------------------------------------------
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>
> didn't
>
> > exist"
> > ------------------------------------------------------------
> > ----- Original Message -----
> > From: <skoehler at buschjena.de>
> > To: <postgis-users at postgis.refractions.net>
> > Sent: Tuesday, December 21, 2004 8:57 AM
> > Subject: [postgis-users] Nearest point on an linestring
> >
> > > Hello,
> > >
> > > with the distance function I can compute the distance between an
> > > linestring and an point. But how can I compute the nearest point on
>
> the
>
> > > linestring to my query point?
> > > I think the distance function needs this point also and so the
>
> information
>
> > > is in the system, how can I use it?
> > >
> > > Thanks
> > > Steffen
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```