Database Reference
In-Depth Information
And, we will require six linesrunning parallel to they axis:
oneline AS (
SELECT ST_MakeLine(ST_Translate($1,
-10, 10.0), ST_Translate($1, -10, -10)) AS
the_geom
),
twoline AS (
SELECT ST_MakeLine(ST_Translate($1, 0,
10.0), ST_Translate($1, 0, -10)) AS the_geom
),
threeline AS (
SELECT ST_MakeLine(ST_Translate($1, 10,
10.0), ST_Translate($1, 10, -10)) AS the_geom
),
fourline AS (
SELECT ST_MakeLine(ST_Translate($1, 20,
10.0), ST_Translate($1, 20, -10)) AS the_geom
),
fiveline AS (
SELECT ST_MakeLine(ST_Translate($1, 30,
10.0), ST_Translate($1, 30, -10)) AS the_geom
),
sixline AS (
SELECT ST_MakeLine(ST_Translate($1, 40,
10.0), ST_Translate($1, 40, -10)) AS the_geom
),
To use these for polygon construction, we will require them to have nodes where
they cross and touch. A
UNION ALL
function will combine these lines in a single
record;
ST_Union
will provide the geometric processing necessary to construct
the nodes of interest and will combine our lines into a single entity ready for
chp04.polygonize_to_multi
:
combined AS (
SELECT ST_Union(the_geom) AS the_geom
FROM
