[postgis-users] ST_Polygonize give different results on same set of linestrings

[Sandro Santilli]

On Thu, Sep 07, 2017 at 01:46:18PM +0000, Pierre Racine wrote:
> Hi,
> 
> Is it normal that ST_Polygonize() gives two different results depending on if the linestrings are ST_Union() before calling it or not?

ST_Polygonize only works when the input is noded (no line
interior intersects any other line). ST_Union performs
noding when missing, so it would hcange ST_Polygonize output
IFF the original input had intersections.

--strk;