Database Reference
In-Depth Information
WHERE ST_Intersects(ST_SetSRID(a.the_geom,
3734), b.the_geom)
),
linework AS (
SELECT chp02.polygon_to_line(the_geom) AS
the_geom FROM
vintersect
),
polylines AS (
SELECT
((ST_Dump(ST_Union(lw.the_geom))).geom)::geometry(linestring,
3734) AS the_geom FROM
linework AS lw
),
externalbounds AS (
SELECT chp02.polygon_to_line(the_geom) AS
the_geom FROM
voronoi_hydro
)
SELECT (ST_Dump(ST_Union(p.the_geom))).geom
FROM
polylines p, externalbounds b
WHERE NOT ST_DWithin(p.the_geom,
b.the_geom, 5)
;
Now,wehaveasecond-levelapproximationoftheskeleton(showninthefollowing
screenshot). It is messy, but starts to highlight that centerline that we seek:
