1.4 KiB
1.4 KiB
Voronoi
Function to construct the Voronoi Diagram from a dataset of scatter points, clipped to the significant area
PostGIS wil include this in future versions (doc for dev branch) and will perform faster for sure, but in the meantime...
CDB_Voronoi (geom geometry[], buffer numeric DEFAULT 0.5, tolerance numeric DEFAULT 1e-9)
Arguments
| Name | Type | Description |
|---|---|---|
| geom | geometry[] | Array of points's geometries |
| buffer | numeric | enlargment ratio for the envelope area used for the restraints |
| tolerance | numeric | Delaunay tolerance, optional |
Returns
| Column Name | Type | Description |
|---|---|---|
| geom | geometry collection | Collection of polygons of the Voronoi cells |
Example Usage
WITH a AS (
SELECT
ARRAY[ST_GeomFromText('POINT(2.1744 41.403)', 4326),ST_GeomFromText('POINT(2.1228 41.380)', 4326),ST_GeomFromText('POINT(2.1511 41.374)', 4326),ST_GeomFromText('POINT(2.1528 41.413)', 4326),ST_GeomFromText('POINT(2.165 41.391)', 4326),ST_GeomFromText('POINT(2.1498 41.371)', 4326),ST_GeomFromText('POINT(2.1533 41.368)', 4326),ST_GeomFromText('POINT(2.131386 41.41399)', 4326)] AS geomin
)
SELECT
st_transform(
(st_dump(CDB_voronoi(geomin, 0.2, 1e-9)
)).geom
, 3857) as the_geom_webmercator
FROM a;