h3

CORE
​H3 is Uber’s Hexagonal Hierarchical Spatial Index. Full documentation of the project can be found at h3geo. You can also learn more about H3 in the Spatial Indexes section of this documentation.
H3_BOUNDARY
H3_BOUNDARY(index)
Description
Returns a geography representing the H3 cell. It will return null on error (invalid input).
index: VARCHAR(16) The H3 cell index as hexadecimal.
Return type
GEOMETRY
Example
1
SELECT carto.H3_BOUNDARY('84390cbffffffff');
2
-- POLYGON ((-3.5769274353957314 40.613438595935165, -3.85975632308016 40.525472355369885, -3.899552298996668 40.28411330409504, ...
H3_CENTER
H3_CENTER(index)
Description
Returns the center of the H3 cell as a GEOMETRY point. It will return null on error (invalid input).
index: VARCHAR(16) The H3 cell index.
Return type
GEOMETRY
Example
1
SELECT carto.H3_CENTER('84390cbffffffff');
2
-- POINT (-3.6176032466282892 40.37254058216577)
H3_COMPACT
H3_COMPACT(indexArray)
Description
Returns an array with the indexes of a set of hexagons across multiple resolutions that represent the same area as the input set of hexagons.
indexArray: VARCHAR(16)[] of H3 cell indices of the same resolution as hexadecimal.
Return type
VARCHAR(16)[]
Example
1
SELECT carto.H3_COMPACT(ARRAY['85390ca3fffffff', '85390ca7fffffff', '85390cabfffffff','85390caffffffff', '85390cb3fffffff', '85390cb7fffffff', '85390cbbfffffff']);
2
-- { 84390cbffffffff }
H3_DISTANCE
H3_DISTANCE(origin, destination)
Description
Returns the grid distance between two hexagon indexes. This function may fail to find the distance between two indexes if they are very far apart or on opposite sides of a pentagon. Returns null on failure or invalid input.
origin: VARCHAR(16) The H3 cell index as hexadecimal.
destination: VARCHAR(16) The H3 cell index as hexadecimal.
Return type
BIGINT
Example
1
SELECT carto.H3_DISTANCE('84390c1ffffffff', '84390cbffffffff');
2
-- 1
tip
If you want the distance in meters use ST_DISTANCE between the cells (H3_BOUNDARY) or their centroid.
H3_FROMGEOGPOINT
H3_FROMGEOGPOINT(point, resolution)
Description
Returns the H3 cell index that the point belongs to in the required resolution. It will return null on error (invalid geography type or resolution out of bounds).
point: GEOMETRY point to get the H3 cell from.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
VARCHAR(16)
Example
1
SELECT carto.H3_FROMGEOGPOINT(ST_POINT(-3.7038, 40.4168), 4);
2
-- 84390cbffffffff
tip
If you want the cells covered by a POLYGON see H3_POLYFILL.
H3_FROMLONGLAT
H3_FROMLONGLAT(longitude, latitude, resolution)
Description
Returns the H3 cell index that the point belongs to in the required resolution. It will return null on error (resolution out of bounds).
longitude: DOUBLE PRECISION horizontal coordinate of the map.
latitude: DOUBLE PRECISION vertical coordinate of the map.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
VARCHAR(16)
Example
1
SELECT carto.H3_FROMLONGLAT(-3.7038, 40.4168, 4);
2
-- 84390cbffffffff
H3_HEXRING
H3_HEXRING(origin, size)
Description
Returns all cell indexes in a hollow hexagonal ring centered at the origin in no particular order. Unlike H3_KRING, this function will throw an exception if there is a pentagon anywhere in the ring.
origin: VARCHAR(16) H3 cell index of the origin.
size: INT size of the ring (distance from the origin).
Return type
VARCHAR(16)[]
Example
1
SELECT carto.H3_HEXRING('84390cbffffffff', 1);
2
-- { 84392b5ffffffff,
3
--   84390c9ffffffff,
4
--   84390c1ffffffff,
5
--   84390c3ffffffff,
6
--   84390ddffffffff,
7
--   84392b7ffffffff }
H3_INT_TOSTRING
H3_INT_TOSTRING(index)
Description
Converts the integer representation of the H3 index to the string representation.
index: INT The H3 cell index.
Return type
VARCHAR(16)
Example
1
SELECT carto.H3_INT_TOSTRING(595478781590765567);
2
-- 84390cbffffffff
H3_ISPENTAGON
H3_ISPENTAGON(index)
Description
Returns true if given H3 index is a pentagon. Returns false otherwise, even on invalid input.
index: VARCHAR(16) The H3 cell index as hexadecimal.
Return type
BOOLEAN
Example
1
SELECT carto.H3_ISPENTAGON('84390cbffffffff');
2
-- false
1
SELECT carto.H3_ISPENTAGON('8075fffffffffff');
2
-- true
H3_ISVALID
H3_ISVALID(index)
Description
Returns true when the given index is valid, false otherwise.
index: VARCHAR(16) The H3 cell index as hexadecimal.
Return type
BOOLEAN
Examples
1
SELECT carto.H3_ISVALID('84390cbffffffff');
2
-- true
1
SELECT carto.H3_ISVALID('1');
2
-- false
H3_KRING
H3_KRING(origin, size)
Description
Returns all cell indexes in a filled hexagonal k-ring centered at the origin in no particular order.
origin: VARCHAR(16) H3 cell index of the origin.
size: INT size of the ring (distance from the origin).
Return type
VARCHAR(16)[]
Example
1
SELECT carto.H3_KRING('84390cbffffffff', 1);
2
-- { 84390cbffffffff,
3
--   84390c9ffffffff,
4
--   84390c1ffffffff,
5
--   84390c3ffffffff,
6
--   84390ddffffffff,
7
--   84392b7ffffffff,
8
--   84392b5ffffffff }
H3_KRING_DISTANCES
H3_KRING_DISTANCES(origin, size)
Description
Returns all cell indexes and their distances in a filled hexagonal k-ring centered at the origin in no particular order.
origin: VARCHAR(16) H3 cell index of the origin.
size: INT size of the ring (distance from the origin).
Return type
JSON[]
Example
1
SELECT carto.H3_KRING_DISTANCES('84390cbffffffff', 1);
2
-- {{"index": "84390cbffffffff", "distance": 0}"
3
--  {"index": "84390c9ffffffff", "distance": 1}
4
--  {"index": "84390c1ffffffff", "distance": 1}
5
--  {"index": "84390c3ffffffff", "distance": 1}
6
--  {"index": "84390ddffffffff", "distance": 1}
7
--  {"index": "84392b7ffffffff", "distance": 1}
8
--  {"index": "84392b5ffffffff", "distance": 1}}
H3_POLYFILL
H3_POLYFILL(geom, resolution [, mode])
Description
Returns an array of H3 cell indexes contained in the given geometry at a given level of detail. Containment is determined by the mode: center, intersects, contains.
geom: GEOMETRY representing the shape to cover.
resolution: INT level of detail. The value must be between 0 and 15 (H3 resolution table).
mode (optional): VARCHAR
center (default) returns the indexes of the H3 cells which centers intersect the input geometry (polygon). The resulting H3 set does not fully cover the input geometry, however, this is significantly faster that the other modes. This mode is not compatible with points or lines.
intersects returns the indexes of the H3 cells that intersect the input geometry. The resulting H3 set will completely cover the input geometry (point, line, polygon).
contains returns the indexes of the H3 cells that are entirely contained inside the input geometry (polygon). This mode is not compatible with points or lines.
Mode center:
Mode intersects:
Mode contains:
Return type
VARCHAR(16)[]
Examples
1
SELECT carto.H3_POLYFILL(
2
  ST_GEOMFROMTEXT('POLYGON ((-3.71219873428345 40.413365349070865, -3.7144088745117 40.40965661286395, -3.70659828186035 40.409525904775634, -3.71219873428345 40.413365349070865))'),
3
  9
4
);
5
-- [89390cb1b4bffff]
1
SELECT h3
2
FROM UNNEST(carto.H3_POLYFILL(
3
  ST_GEOMFROMTEXT('POLYGON ((-3.71219873428345 40.413365349070865, -3.7144088745117 40.40965661286395, -3.70659828186035 40.409525904775634, -3.71219873428345 40.413365349070865))'),
4
  9
5
)) AS h3;
6
-- 89390cb1b4bffff
1
SELECT h3
2
FROM <database>.<schema>.<table>,
3
  UNNEST(carto.H3_POLYFILL(geom, 9)) AS h3;
1
SELECT carto.H3_POLYFILL(
2
  ST_GEOMFROMTEXT('POLYGON ((-3.71219873428345 40.413365349070865, -3.7144088745117 40.40965661286395, -3.70659828186035 40.409525904775634, -3.71219873428345 40.413365349070865))'),
3
  9, 'intersects'
4
);
5
-- [89390cb1b4fffff, 89390ca3497ffff, 89390ca34b3ffff, 89390cb1b4bffff, 89390ca3487ffff, 89390cb1b5bffff]
1
SELECT h3
2
FROM UNNEST(carto.H3_POLYFILL(
3
  ST_GEOMFROMTEXT('POLYGON ((-3.71219873428345 40.413365349070865, -3.7144088745117 40.40965661286395, -3.70659828186035 40.409525904775634, -3.71219873428345 40.413365349070865))'),
4
  9, 'intersects'
5
)) AS h3;
6
-- 89390cb1b4fffff
7
-- 89390ca3497ffff
8
-- 89390ca34b3ffff
9
-- 89390cb1b4bffff
10
-- 89390ca3487ffff
11
-- 89390cb1b5bffff
1
SELECT h3
2
FROM <database>.<schema>.<table>,
3
  UNNEST(carto.H3_POLYFILL(geom, 9, 'intersects')) AS h3;
H3_STRING_TOINT
H3_STRING_TOINT(index)
Description
Converts the string representation of the H3 index to the integer representation.
index: VARCHAR(16) The H3 cell index.
Return type
INT
Example
1
SELECT carto.H3_STRING_TOINT('84390cbffffffff');
2
-- 595478781590765567
H3_TOCHILDREN
H3_TOCHILDREN(index, resolution)
Description
Returns an array with the indexes of the children/descendents of the given hexagon at the given resolution.
index: VARCHAR(16) The H3 cell index as hexadecimal.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
VARCHAR(16)[]
Example
1
SELECT carto.H3_TOCHILDREN('83390cfffffffff', 4);
2
-- { 84390c1ffffffff,
3
--   84390c3ffffffff,
4
--   84390c5ffffffff
5
--   84390c7ffffffff,
6
--   84390c9ffffffff,
7
--   84390cbffffffff,
8
--   84390cdffffffff }
H3_TOPARENT
H3_TOPARENT(index, resolution)
Description
Returns the H3 cell index of the parent of the given hexagon at the given resolution.
index: VARCHAR(16) The H3 cell index as hexadecimal.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
VARCHAR
Example
1
SELECT carto.H3_TOPARENT('84390cbffffffff', 3);
2
-- 83390cfffffffff
H3_UNCOMPACT
H3_UNCOMPACT(indexArray, resolution)
Description
Returns an array with the indexes of a set of hexagons of the same resolution that represent the same area as the compacted input hexagons.
indexArray: VARCHAR(16) of H3 cell indices as hexadecimal.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
VARCHAR(16)[]
Example
1
SELECT carto.H3_UNCOMPACT(ARRAY['84390cbffffffff'], 5);
2
-- { 85390ca3fffffff,
3
--   85390ca7fffffff,
4
--   85390cabfffffff,
5
--   85390caffffffff,
6
--   85390cb3fffffff,
7
--   85390cb7fffffff,
8
--   85390cbbfffffff }
SQL Reference
quadbin
Last modified 1mo ago