ST_ConstrainedDelaunayTriangles
Name
ST_ConstrainedDelaunayTriangles — Return a constrained Delaunay triangulation around the given input geometry.
Synopsis
    
     geometry
     
      ST_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
        
         ST_ConstrainedDelaunayTriangles of 2 polygons 
 
select ST_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)
                   )
	   );
       
  |