Database Reference
In-Depth Information
SELECT id::int4, ST_X(the_geom)::float8 as x,
ST_Y(the_geom)::float8 AS y
FROM cleveland_ways_vertices_pgr w, DD d
WHERE w.id = d.node
)
SELECT * FROM dd_points
')
),
alphapoints AS (
SELECT ST_MakePoint((pgr_alphashape).x,
(pgr_alphashape).y) FROM alphashape
),
alphaline AS (
SELECT ST_Makeline(ST_MakePoint) FROM
alphapoints
)
SELECT 1 as id,
ST_SetSRID(ST_MakePolygon(ST_AddPoint(ST_Makeline,
ST_StartPoint(ST_Makeline))), 4326) AS the_geom
FROM alphaline
);
Theprecedingscriptgivesusaveryinterestingshape(Maptilesby
Stamen Design,
under CC BY 3.0
, Data by
OpenStreetMap, under CC BY SA
). See the following
screenshot:
