[postgis-users] breake lines

[Martin Davis]

Have you tried using ST_Split passing each input line and for the second
argument a MultiLineString comprised of all lines that it might intersect
(obtained via BBOX or ST_Intersects query)?  It seems like that should not
create any duplicate linework from the input line.

As far as I know there's no other way to do this using current PostGIS
functions.   It's an interesting requirement - it sounds like essentially
you want to node one layer against another.  There's actually the machinery
to do this internally in PostGIS/GEOS, but it's never come up as a
requirement before, so has not been exposed as a function.

What is your use case?

On Tue, Sep 3, 2019 at 9:48 AM <paul.malm at lfv.se> wrote:

> If I split lines with another line layer, I will get a lot of duplicaded
> line segments since the lines could be intersected several times. It is not
> possible to use update on the table when splitting one geomety to two.
> I think it must be possible, but I’m not that skilled in SQL and I’ve not
> found any examples on the net.
>
>
>
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