sicob_forceclosed.sql

SET CLIENT_ENCODING TO 'utf8';
CREATE OR REPLACE FUNCTION public.sicob_forceclosed(geom geometry)
 RETURNS geometry
 LANGUAGE plpgsql
 IMMUTABLE COST 42
AS $function$BEGIN
  IF ST_IsClosed(geom) THEN
    RETURN geom;
  ELSIF GeometryType(geom) = 'LINESTRING' THEN
    SELECT ST_AddPoint(geom, ST_StartPoint(geom)) INTO geom;
  ELSIF GeometryType(geom) ~ '(MULTI|COLLECTION)' THEN
    -- Recursively deconstruct parts
    WITH parts AS (
      SELECT ST_ForceClosed(gd.geom) AS closed_geom FROM ST_Dump(geom) AS gd
    ) -- Reconstitute parts
    SELECT ST_Collect(closed_geom) INTO geom
    FROM parts;
  END IF;
  IF NOT ST_IsClosed(geom) THEN
    RAISE EXCEPTION 'Could not close geometry';
  END IF;
  RETURN geom;
END;$function$