You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
57 lines
1.6 KiB
57 lines
1.6 KiB
set client_min_messages to error;
|
|
\set VERBOSITY TERSE
|
|
|
|
-- Check correctness of an hexagons grid
|
|
--
|
|
-- Cells must have no overlaps and have a number of
|
|
-- intersections with other cells between 2 and 6
|
|
--
|
|
|
|
WITH
|
|
params AS ( SELECT ST_MakeEnvelope(10, 10, 20, 20) as env, 2 as radius ),
|
|
grid AS ( SELECT CDB_HexagonGrid(env, radius) AS cell from params),
|
|
igrid AS ( SELECT row_number() over (), cell from grid )
|
|
|
|
SELECT count(row_number) as r1, sum(st_npoints(cell)) as r2, 'count / npoints' as err
|
|
FROM igrid g1
|
|
|
|
UNION ALL
|
|
|
|
SELECT g1.row_number as r1, g2.row_number as r2, 'overlap' as err
|
|
FROM igrid g1, igrid g2
|
|
WHERE g2.row_number > g1.row_number AND
|
|
ST_Overlaps(g1.cell, g2.cell)
|
|
|
|
UNION ALL
|
|
|
|
SELECT g1.row_number, count(g2.row_number) as r2, 'n intersections' as err
|
|
FROM igrid g1, igrid g2
|
|
WHERE g1.row_number != g2.row_number AND
|
|
ST_Intersects(g1.cell, g2.cell)
|
|
GROUP BY g1.row_number
|
|
HAVING count(g2.row_number) > 6 OR count(g2.row_number) < 2
|
|
|
|
UNION ALL
|
|
|
|
SELECT g1.row_number, null::integer, 'centroid out of extent' as err
|
|
FROM igrid g1, params
|
|
WHERE NOT ST_Intersects(ST_Centroid(g1.cell), params.env)
|
|
|
|
;
|
|
|
|
|
|
-- Check robustness of HexagonGrid generation
|
|
|
|
WITH
|
|
params AS ( SELECT
|
|
ST_MakeEnvelope(-20037508.5,20037507,-20037508,20037507.5) as env,
|
|
0.002 as radius ),
|
|
grid AS ( SELECT CDB_HexagonGrid(env, radius) AS cell from params)
|
|
SELECT '#160', count(cell) > 23000 from grid;
|
|
|
|
-- Check small grids are generated...
|
|
SELECT COUNT(*) FROM cartodb.CDB_HexagonGrid(ST_MakeEnvelope(0,0,1000,1000,3857), 10);
|
|
|
|
-- But large grids produce an error
|
|
SELECT COUNT(*) FROM cartodb.CDB_HexagonGrid(ST_MakeEnvelope(0,0,1000,1000,3857), 1);
|