[postgis-users] Node Polygon Intersections

[Sandro Santilli]

On Wed, Jan 06, 2016 at 04:55:59PM -0200, Lucas Ferreira Mation wrote:

> The first step is node all polygon intersections. Is there a simple way to
> do this in Postgis, making sure that all polygons involved in an
> intersection have "nodes" at the intersection point?

There's an ST_Node function you can use but as you mention it will
loose the reference to the source record because you'll have to
node all geometries of the set at once.

I'd keep trying with the PostGIS Topology approach, just making
the load incremental. Make sure to use PostGIS-2.2.1 which got
a few robustness fixes recently.

> How does Postgis handdles the cases where the coordinates of the
>  intersection (of the polygon borders) can´t be represented with double
> precision?

The intersection point is moved to the nearest representable spot.

--strk;