Indexing functions

These functions are used for finding the H3 cell index containing coordinates, and for finding the center and boundary of H3 cells.

latLngToCell

Indexes the location at the specified resolution, providing the index of the cell containing the location. This buckets the geographic point into the H3 grid. For more information, see the algorithm description.

C

H3Error latLngToCell(const LatLng *g, int res, H3Index *out);

Returns 0 (E_SUCCESS) on success.

Java

long latLngToCell(double lat, double lng, int res);
String latLngToCellAddress(double lat, double lng, int res);

JavaScript (Live)

h3.latLngToCell(lat, lng, res)

Live Editor

function example() { const lat = 45; const lng = 40; const res = 2; return h3.latLngToCell(lat, lng, res); }

function example() {
  const lat = 45;
  const lng = 40;
  const res = 2;
  return h3.latLngToCell(lat, lng, res);
}

Result

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Python

h3.latlng_to_cell(lat, lng, resolution)

Shell

$ h3 latLngToCell --help
h3: Convert degrees latitude/longitude coordinate to an H3 cell
H3 4.1.0

    latLngToCell    Convert degrees latitude/longitude coordinate to an H3 cell
    -h, --help  Show this help message.
    -r, --resolution <res>  Required. Resolution, 0-15 inclusive.
    --lat, --latitude <lat> Required. Latitude in degrees.
    --lng, --longitude <lng>    Required. Longitude in degrees.
    -f, --format <FMT>  'json' for "CELL"\n, 'newline' for CELL\n (Default: json)

$ h3 latLngToCell --lat 45 --lng 40 -r 2
"822d57fffffffff"

cellToLatLng

Finds the center of the cell in grid space. See the algorithm description for more information.

The center will drift versus the centroid of the cell on Earth due to distortion from the gnomonic projection within the icosahedron face it resides on and its distance from the center of the icosahedron face.

C

H3Error cellToLatLng(H3Index cell, LatLng *g);

Returns 0 (E_SUCCESS) on success.

Java

LatLng cellToLatLng(long cell);
LatLng cellToLatLng(String cellAddress);

JavaScript (Live)

h3.cellToLatLng(cell)

Live Editor

function example() { const cell = '85283473fffffff'; return h3.cellToLatLng(cell); }

function example() {
  const cell = '85283473fffffff';
  return h3.cellToLatLng(cell);
}

Result

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Python

h3.cell_to_latlng(cell)

Shell

$ h3 cellToLatLng --help
h3: Convert an H3Cell to a coordinate
H3 4.1.0

    cellToLatLng    Convert an H3Cell to a coordinate
    -h, --help  Show this help message.
    -c, --cell <index>  Required. H3 Cell
    -f, --format <FMT>  'json' for [lat, lng], 'wkt' for a WKT POINT, 'newline' for lat\nlng\n (Default: json)

$ h3 cellToLatLng -c 85283473fffffff
[37.3457933754, -121.9763759726]

cellToBoundary

Finds the boundary of the cell. For more information, see the algorithm description.

C

H3Error cellToBoundary(H3Index cell, CellBoundary *bndry);

Returns 0 (E_SUCCESS) on success.

Java

List<LatLng> cellToBoundary(long cell);
List<LatLng> cellToBoundary(String cellAddress);

JavaScript (Live)

h3.cellToBoundary(cell, [formatAsGeoJson])

Live Editor

function example() { const cell = '85283473fffffff'; return h3.cellToBoundary(cell); }

function example() {
  const cell = '85283473fffffff';
  return h3.cellToBoundary(cell);
}

Result

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Python

h3.cell_to_boundary(cell)

Returns tuple of lat/lng tuples. For GeoJSON compatibility (lng/lat order), see the h3-py docs.

Shell

$ h3 cellToBoundary --help
h3: Convert an H3 cell to a polygon defining its boundary
H3 4.1.0

    cellToBoundary  Convert an H3 cell to a polygon defining its boundary
    -h, --help  Show this help message.
    -c, --cell <index>  Required. H3 Cell
    -f, --format <FMT>  'json' for [[lat, lng], ...], 'wkt' for a WKT POLYGON, 'newline' for lat\nlng\n... (Default: json)

$ h3 cellToBoundary -c 85283473fffffff
[[37.2713558667, -121.9150803271], [37.3539264509, -121.8622232890], [37.4283411861, -121.9235499963], [37.4201286777, -122.0377349643], [37.3375560844, -122.0904289290], [37.2631979746, -122.0291013092]]