Returns the S2 cell ID, which uniquely identifies the region on Earth that fully contains, or covers, a single Point GEOGRAPHY object.
ST_S2CELLIDFROMPOINT exclusively supports single Point GEOGRAPHY objects, and returns NULL for all other values including
MultiPoint, LineString, Polygon, and an empty GEOGRAPHY object.
Syntax
ST_S2CELLIDFROMPOINT(<geo> [, <cell_level> ])
Parameters
| Parameter | Description | Supported input types |
|---|
<geo> | A single valid GEOGRAPHY Point for which ST_S2CELLIDFROMPOINT calculates and returns the S2 cell that covers it. | GEOGRAPHY |
<cell_level> | The resolution of the S2 cell to return. Valid levels range from 0, the coarsest level, to 30, the finest level. The default level is 30 if unspecified. | BIGINT |
Return Type
ST_S2CELLIDFROMPOINT returns a value of type BIGINT, which may include negative values.
Example
The following code example constructs a dataset containing three GEOGRAPHY objects: a valid Point, an empty Point, and a LineString. The code example computes their S2 cell IDs at cell levels 30 (finest resolution, default) and 10, returning results only for the valid Point. The function returns NULL for the second input because it is empty and contains no geographic data, and for the third input because LineString is not a supported GEOGRAPHY type.
WITH data AS (
SELECT 1 AS id, ST_GEOGFROMTEXT('POINT(-122 47)') AS geo
UNION ALL
SELECT 2 AS id, ST_GEOGFROMTEXT('POINT EMPTY') AS geo
UNION ALL
SELECT 3 AS id, ST_GEOGFROMTEXT('LINESTRING(1 2, 3 4)') AS geo
)
SELECT id,
ST_S2CELLIDFROMPOINT(geo) cell30,
ST_S2CELLIDFROMPOINT(geo, 10) cell10
FROM data;
| id int | cell30 long null | cell10 long null |
|---|
| 1 | 6093613931972369317 | 6093613287902019584 |
| 2 | NULL | NULL |
| 3 | NULL | NULL |
Rows: 3Execution time: 5.60ms
