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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: STRING The H3 cell index as hexadecimal.
Return type
GEOGRAPHY
Example
SELECT CARTO.CARTO.H3_BOUNDARY('84390cbffffffff');
-- { "coordinates": [ [ [ -3.5769274353957314, 40.613438595935165 ], [ -3.85975632308016, 40.525472355369885 ], ...
H3_CENTER
H3_CENTER(index)
Description
Returns the center of the H3 cell as a GEOGRAPHY point. It will return null on error (invalid input).
index: STRING The H3 cell index.
Return type
GEOGRAPHY
Example
SELECT CARTO.CARTO.H3_CENTER('84390cbffffffff');
-- { "coordinates": [ -3.6176032466282892, 40.37254058216577 ], "type": "Point" }
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: ARRAY of H3 cell indices of the same resolution as hexadecimal.
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_COMPACT(ARRAY_CONSTRUCT('85390ca3fffffff', '85390ca7fffffff', '85390cabfffffff', '85390caffffffff', '85390cb3fffffff', '85390cb7fffffff', '85390cbbfffffff'));
-- 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: STRING The H3 cell index as hexadecimal.
destination: STRING The H3 cell index as hexadecimal.
Return type
BIGINT
Example
SELECT CARTO.CARTO.H3_DISTANCE('84390c1ffffffff', '84390cbffffffff');
-- 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: GEOGRAPHY point to get the H3 cell from.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
STRING
Example
SELECT CARTO.CARTO.H3_FROMGEOGPOINT(ST_POINT(-3.7038, 40.4168), 4);
-- 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 horizontal coordinate of the map.
latitude: DOUBLE vertical coordinate of the map.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
STRING
Example
SELECT CARTO.CARTO.H3_FROMLONGLAT(-3.7038, 40.4168, 4);
-- 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: STRING H3 cell index of the origin.
size: INT size of the ring (distance from the origin).
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_HEXRING('84390cbffffffff', 1);
-- 84392b5ffffffff
-- 84390c9ffffffff
-- 84390c1ffffffff
-- 84390c3ffffffff
-- 84390ddffffffff
-- 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
STRING
Example
SELECT CARTO.CARTO.H3_INT_TOSTRING(595478781590765567);
-- 84390cbffffffff
H3_ISPENTAGON
H3_ISPENTAGON(index)
Description
Returns true if given H3 index is a pentagon. Returns false otherwise, even on invalid input.
index: STRING The H3 cell index as hexadecimal.
Return type
BOOLEAN
Example
SELECT CARTO.CARTO.H3_ISPENTAGON('84390cbffffffff');
-- false
SELECT CARTO.CARTO.H3_ISPENTAGON('8075fffffffffff');
-- true
H3_ISVALID
H3_ISVALID(index)
Description
Returns true when the given index is valid, false otherwise.
index: STRING The H3 cell index as hexadecimal.
Return type
BOOLEAN
Examples
SELECT CARTO.CARTO.H3_ISVALID('84390cbffffffff');
-- true
SELECT CARTO.CARTO.H3_ISVALID('1');
-- 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: STRING H3 cell index of the origin.
size: INT size of the ring (distance from the origin).
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_KRING('84390cbffffffff', 1);
-- 84390cbffffffff
-- 84390c9ffffffff
-- 84390c1ffffffff
-- 84390c3ffffffff
-- 84390ddffffffff
-- 84392b7ffffffff
-- 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: STRING H3 cell index of the origin.
size: INT size of the ring (distance from the origin).
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_KRING_DISTANCES('84390cbffffffff', 1);
-- {"index": "84390cbffffffff", "distance": 0}
-- {"index": "84390c9ffffffff", "distance": 1}
-- {"index": "84390c1ffffffff", "distance": 1}
-- {"index": "84390c3ffffffff", "distance": 1}
-- {"index": "84390ddffffffff", "distance": 1}
-- {"index": "84392b7ffffffff", "distance": 1}
-- {"index": "84392b5ffffffff", "distance": 1}
H3_POLYFILL
H3_POLYFILL(geography, resolution)
Description
Returns an array with all the H3 cell indexes with centers contained in a given polygon. It will return null on error (invalid geography type or resolution out of bounds).
geography: GEOGRAPHY polygon or multipolygon representing the shape to cover.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_POLYFILL(
    TO_GEOGRAPHY('POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10))'), 4);
-- 842da29ffffffff
-- 843f725ffffffff
-- 843eac1ffffffff
-- 8453945ffffffff
-- ...
H3_POLYFILL_TABLE (BETA)
H3_POLYFILL_TABLE(input_query, resolution, mode, output_table)
Description
Returns a table with the H3 cell indexes contained in the given geography at a given level of detail. Containment is determined by the mode: center, intersects, contains. All the attributes except the geography will be included in the output table, clustered by the h3 column.
input_query: STRING input data to polyfill. It must contain a column geom with the shape to cover. Additionally, other columns can be included.
resolution: INT level of detail. The value must be between 0 and 15 (H3 resolution table).
mode: STRING
center returns the indexes of the H3 cells which centers intersect the input geography (polygon). The resulting H3 set does not fully cover the input geography, however, this is significantly faster that the other modes. This mode is not compatible with points or lines. Equivalent to H3_POLYFILL.
intersects returns the indexes of the H3 cells that intersect the input geography. The resulting H3 set will completely cover the input geography (point, line, polygon).
contains returns the indexes of the H3 cells that are entirely contained inside the input geography (polygon). This mode is not compatible with points or lines.
output_table: STRING name of the output table to store the results of the polyfill.
Mode center:
Mode intersects:
Mode contains:
Output
The results are stored in the table named <output_table>, which contains the following columns:
h3: STRING the geometry of the considered point.
The rest of columns included in input_query except geom.
Examples
CALL CARTO.CARTO.H3_POLYFILL_TABLE(
  'SELECT TO_GEOGRAPHY(''POLYGON ((-3.71219873428345 40.413365349070865, -3.7144088745117 40.40965661286395, -3.70659828186035 40.409525904775634, -3.71219873428345 40.413365349070865))'') AS geom',
  9, 'intersects',
  '<database>.<schema>.<output_table>'
);
-- The table `<database>.<schema>.<output_table>` will be created
-- with column: h3
CALL CARTO.CARTO.H3_POLYFILL_TABLE(
  'SELECT geom, name, value FROM `<database>.<schema>.<table>`',
  9, 'center',
  '<database>.<schema>.<output_table>'
);
-- The table `<database>.<schema>.<output_table>` will be created
-- with columns: h3, name, value
H3_RESOLUTION
H3_RESOLUTION(index)
Description
Returns the H3 cell resolution as an integer. It will return null on error (invalid input).
index: STRING The H3 cell index.
Return type
INT
Example
SELECT CARTO.CARTO.H3_RESOLUTION('84390cbffffffff');
-- 4
H3_STRING_TOINT
H3_STRING_TOINT(index)
Description
Converts the string representation of the H3 index to the integer representation.
index: STRING The H3 cell index.
Return type
INT
Example
SELECT CARTO.CARTO.H3_STRING_TOINT('84390cbffffffff');
-- 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: STRING The H3 cell index as hexadecimal.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_TOCHILDREN('83390cfffffffff', 4);
-- 84390c1ffffffff
-- 84390c3ffffffff
-- 84390c5ffffffff
-- 84390c7ffffffff
-- 84390c9ffffffff
-- 84390cbffffffff
-- 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: STRING The H3 cell index as hexadecimal.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
STRING
Example
SELECT CARTO.CARTO.H3_TOPARENT('84390cbffffffff', 3);
-- 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: ARRAY of H3 cell indices as hexadecimal.
resolution: INT number between 0 and 15 with the H3 resolution.
Return type
ARRAY
Example
SELECT CARTO.CARTO.H3_UNCOMPACT(ARRAY_CONSTRUCT('84390cbffffffff'), 5);
-- 85390ca3fffffff
-- 85390ca7fffffff
-- 85390cabfffffff
-- 85390caffffffff
-- 85390cb3fffffff
-- 85390cb7fffffff
-- 85390cbbfffffff
data
lds
Last modified 1mo ago