--- title: "CG_ConstrainedDelaunayTriangles" draft: false hidden: true ---

Name

CG_ConstrainedDelaunayTriangles — Return a constrained Delaunay triangulation around the given input geometry.

Synopsis

geometry CG_ConstrainedDelaunayTriangles ( geometry g1 ) ;

Description

Return a Constrained Delaunay triangulation around the vertices of the input geometry. Output is a TIN.

This method needs SFCGAL backend.

Availability: 3.0.0

This function supports 3d and will not drop the z-index.

Examples

CG_ConstrainedDelaunayTriangles of 2 polygons

                                        select CG_ConstrainedDelaunayTriangles(
                                        ST_Union(
                                        'POLYGON((175 150, 20 40, 50 60, 125 100, 175 150))'::geometry,
                                        ST_Buffer('POINT(110 170)'::geometry, 20)
                                        )
                                        );
                                    

ST_DelaunayTriangles of 2 polygons. Triangle edges cross polygon boundaries.

                                        select ST_DelaunayTriangles(
                                        ST_Union(
                                        'POLYGON((175 150, 20 40, 50 60, 125 100, 175 150))'::geometry,
                                        ST_Buffer('POINT(110 170)'::geometry, 20)
                                        )
                                        );
                                    

See Also

ST_DelaunayTriangles , ST_TriangulatePolygon , CG_Tesselate , ST_ConcaveHull , ST_Dump