s2

Our S2 module is based on a port of the official S2 geometry library created by Google. For more information about S2 check the library's website or the Spatial Indexes section of this documentation.

S2_BOUNDARY

S2_BOUNDARY(id)

Description

Returns the boundary for a given S2 cell ID. We extract the boundary by getting the corner longitudes and latitudes, then enclose it in a GeoJSON and finally transform it into geography.

Input parameters

• id: INT64 S2 cell ID to get the boundary geography from.

Return type

GEOGRAPHY

Example

carto-un

SELECT `carto-un`.carto.S2_BOUNDARY(955378847514099712);
-- POLYGON((-3.41955272426037 40.25850071217, -3.41955272426037  ...

carto-un-eu

manual

S2 Cell edges are spherical geodesics. The boundary edges can be interpreted as straight lines in other GIS tools, so to export the exact shape of the cells, use ST_GEOGFROM(ST_ASGEOJSON(geog). In this process, BigQuery will add intermediate points to preserve the geodesic curves.

S2_CENTER

S2_CENTER(id)

Description

Returns a POINT corresponding to the centroid of an S2 cell, given its ID.

Input parameters

• id: INT64 S2 cell ID to get the boundary geography from.

Return type

GEOGRAPHY

Example

carto-un

SELECT `carto-un`.carto.S2_CENTER(955378847514099712);
-- POINT(-3.58126923539589 40.4167087628243)

carto-un-eu

manual

S2_FROMGEOGPOINT

S2_FROMGEOGPOINT(point, resolution)

Description

Returns the S2 cell ID of a given point at a requested resolution.

Input parameters

• point: GEOGRAPHY point to get the ID from.

• resolution: INT64 level of detail or zoom.

Return type

INT64

Example

carto-un

SELECT `carto-un`.carto.S2_FROMGEOGPOINT(ST_GEOGPOINT(-3.7038, 40.4168), 8);
-- 955378847514099712

carto-un-eu

manual

S2_FROMHILBERTQUADKEY

S2_FROMHILBERTQUADKEY(hquadkey)

Description

Returns the conversion of a Hilbert quadkey (a.k.a Hilbert curve quadtree ID) into a S2 cell ID.

Input parameters

• hquadkey: STRING Hilbert quadkey to be converted.

Return type

INT64

Example

carto-un

SELECT `carto-un`.carto.S2_FROMHILBERTQUADKEY('0/12220101');
-- 955378847514099712

carto-un-eu

manual

S2_FROMLONGLAT

S2_FROMLONGLAT(longitude, latitude, resolution)

Description

Returns the S2 cell ID for a given longitude, latitude and zoom resolution.

Input parameters

• longitude: FLOAT64 horizontal coordinate on the map.

• latitude: FLOAT64 vertical coordinate on the map.

• resolution: INT64 level of detail or zoom.

Return type

INT64

Example

carto-un

SELECT `carto-un`.carto.S2_FROMLONGLAT(-3.7038, 40.4168, 8);
-- 955378847514099712

carto-un-eu

manual

S2_FROMTOKEN

S2_FROMTOKEN(token)

Description

Returns the conversion of a token into a S2 cell ID.

Input parameters

• token: STRING S2 cell hexified ID.

Return type

INT64

Example

carto-un

SELECT `carto-un`.carto.S2_FROMTOKEN('0d423');
-- 955378847514099712

carto-un-eu

manual

S2_FROMUINT64REPR

S2_FROMUINT64REPR(uid)

Description

Returns the cell ID from a UINT64 representation.

Input parameters

• uid: STRING UINT64 representation of a S2 cell ID.

Return type

INT64

Example

carto-un

SELECT `carto-un`.carto.S2_FROMUINT64REPR('9926595690882924544');
-- -8520148382826627072

carto-un-eu

manual

S2_RESOLUTION

S2_RESOLUTION(index)

Description

Returns the S2 cell resolution as an integer.

Input parameters

• index: STRING The S2 cell index.

Return type

INT64

Example

carto-un

SELECT `carto-un`.carto.S2_RESOLUTION(955378847514099712);
-- 9

carto-un-eu

manual

S2_TOCHILDREN

S2_TOCHILDREN(index, resolution)

Description

Returns an array with the S2 indexes of the children/descendents of the given hexagon at the given resolution.

Input parameters

• index: STRING The S2 cell index.

• resolution: INT64 number between 0 and 30 with the S2 resolution.

Return type

ARRAY<STRING>

Example

carto-un

SELECT `carto-un`.carto.S2_TOCHILDREN(955378847514099712, 10);
-- 955365653374566400
-- 955374449467588608
-- 955383245560610816
-- 955392041653633024

carto-un-eu

manual

S2_TOHILBERTQUADKEY

S2_TOHILBERTQUADKEY(id)

Description

Returns the conversion of a S2 cell ID into a Hilbert quadkey (a.k.a Hilbert curve quadtree ID).

Input parameters

• id: INT64 S2 cell ID to be converted.

Return type

STRING

Example

carto-un

SELECT `carto-un`.carto.S2_TOHILBERTQUADKEY(955378847514099712);
-- 0/12220101

carto-un-eu

manual

S2_TOTOKEN

S2_TOTOKEN(id)

Description

Returns the conversion of a S2 cell ID into a token (S2 cell hexified ID).

Input parameters

• id: INT64 S2 cell ID.

Return type

STRING

Example

carto-un

SELECT `carto-un`.carto.S2_TOTOKEN(955378847514099712);
-- 0d423

carto-un-eu

manual

S2_TOUINT64REPR

S2_TOUINT64REPR(id)

Description

Returns the UINT64 representation of a cell ID.

Input parameters

• id: INT64 S2 cell ID.

Return type

STRING

Example

carto-un

SELECT `carto-un`.carto.S2_TOUINT64REPR(-8520148382826627072);
-- 9926595690882924544

carto-un-eu

manual

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 960401.