[postgis-users] splitting a linestring with points

Alexandre Neto senhor.neto at gmail.com
Fri Feb 9 04:31:14 PST 2018


Beware that hitting a line with a point can be tricky in terms of accuracy.
Unless the point is snapped to one of the line's vertices, if you zoom
enough, it will not be on top of the line. That may be the reason why you
are not getting the desired results.

Olivier Leprêtre <o.lepretre at gmail.com> escreveu no dia sexta, 9/02/2018 às
09:55:

> Hi Martin
>
> I hoped but it's doesn't with results from st_collectionExtract(st_Split())
>
> Olivier
>
> -----Message d'origine-----
> De : postgis-users [mailto:postgis-users-bounces at lists.osgeo.org] De la
> part de Martijn Meijers
> Envoyé : vendredi 9 février 2018 09:15
> À : postgis-users at lists.osgeo.org
> Objet : Re: [postgis-users] splitting a linestring with points
>
> st_dump would make it possible, no?
>
> select st_astext((st_dump('MULTILINESTRING((0 0, 10 10), (20 20, 30
> 30))')).geom);
>          st_astext
> -------------------------
>   LINESTRING(0 0,10 10)
>   LINESTRING(20 20,30 30)
> (2 rows)
>
>
>
> On 08-02-18 21:48, Olivier Leprêtre wrote:
> >
> > Hi,
> >
> > I want to break a linestring into linestrings by breaking it with a
> > set of points along this line. This appeared easy at first but
> > finally, I tried using st_split(line, set of points) but this returns
> > multilinestrings when I just wants linestrings. I tried several
> > functions like st_dump, st_geometryN, stcollectionextract and so on
> > after st_split but did not find how could I get only rows of
> > linestring splitted by the points acting like blades on the first
> > linestring.
> >
> > Thanks for any help,
> >
> > Olivier
> >
> >
> > <
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-- 
Alexandre Neto
---------------------
@AlexNetoGeo
http://sigsemgrilhetas.wordpress.com
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