State of sfcgal_triangulate in PostGIS

[hjanetzek]

Is there a reason why lwgeom_sfcgal already includes the code for triangulate_2dz but it is not (yet) exported with with sfcgal.sql?

[vmora]

the triangulate_2dz code has a bug, I'll try and fix it before the next release.

[vmora]

My bad, there is no bug, it is just that, for polygons with holes, the triangles inside holes are not filtered (the filtering function is not called).

[tomvantilburg]

This would still be a nice feature to have available from postgis. Afaik there are 2 functions that already do triangulation but in different ways. ST_DelaunayTriangulation is unconstrained and only does points while ST_Tesselate only does polygons.

I have it running as st_triangulate2dz, and up to now without bugs.
To activate it in postgis:

CREATE OR REPLACE FUNCTION st_triangulate2dz(geometry)
  RETURNS geometry AS
'$libdir/postgis-2.3', 'sfcgal_triangulate'
  LANGUAGE c IMMUTABLE STRICT
  COST 100;

[Komzpa]

PostGIS ticket:
https://trac.osgeo.org/postgis/ticket/4198

[lbartoletti]

ST_ConstrainedDelaunayTriangles (sfcgal.triangulate_2dz) is available in Postgis