Index inspection functions - H3

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These functions provide metadata about an H3 index, such as its resolution or base cell, and provide utilities for converting into and out of the 64-bit representation of an H3 index.

getResolution

Returns the resolution of the index. (Works for cells, edges, and vertexes.)

int getResolution(H3Index h);

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java

int getResolution(long h3);
int getResolution(String h3Address);

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h3.getResolution(h)

function example() {
  const h = '85283473fffffff';
  return h3.getResolution(h);
}

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h3.get_resolution(h)

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cell.Resolution()

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sql

h3_get_resolution(h)

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$ h3 getResolution --help
h3: Extracts the resolution (0 - 15) from the H3 cell
H3 4.1.0

	getResolution	Extracts the resolution (0 - 15) from the H3 cell
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell

bash

$ h3 getResolution -c 85283473fffffff
5

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getBaseCellNumber

Returns the base cell number of the index. (Works for cells, edges, and vertexes.)

int getBaseCellNumber(H3Index h);

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java

int getBaseCellNumber(long h3);
int getBaseCellNumber(String h3Address);

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h3.getBaseCellNumber(h)

function example() {
  const h = '85283473fffffff';
  return h3.getBaseCellNumber(h);
}

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h3.get_base_cell_number(h)

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cell.BaseCellNumber()

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sql

h3_get_base_cell_number(h)

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$ h3 getBaseCellNumber --help
h3: Extracts the base cell number (0 - 121) from the H3 cell
H3 4.1.0

	getBaseCellNumber	Extracts the base cell number (0 - 121) from the H3 cell
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell

bash

$ h3 getBaseCellNumber -c 85283473fffffff
20

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getIndexDigit

Returns an indexing digit of the index. Works for cells, edges and vertexes.

H3Error getIndexDigit(H3Index h, int res, H3Index *out);

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java

int getIndexDigit(long h3, int res);
int getIndexDigit(String h3Address, int res);

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h3.getIndexDigit(h, res)

function example() {
  const h = '85283473fffffff';
  const res = 2;
  return h3.getIndexDigit(h, res);
}

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h3.get_index_digit(h, res)

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cell.IndexDigit(res)

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sql

h3_get_index_digit(h, res)

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$ h3 getIndexDigit --help
h3: Extracts the indexing digit (0 - 7) from the H3 cell
H3 4.3.0

	getIndexDigit	Extracts the indexing digit (0 - 7) from the H3 cell
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell
	-r, --res <res>	Required. Indexing resolution (1 - 15)

bash

$ h3 getIndexDigit -c 85283473fffffff -r 2
7

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Digits are 1-indexed starting with the resolution 1 digit.

This function will return unused index digits as well as used ones, in that case they will be 7 for valid cells.

constructCell

Creates a cell from its components (resolution, base cell number, and indexing digits). This is the inverse operation of getResolution, getBaseCellNumber, and getIndexDigit. Only allows for constructing valid H3 cells, and will return an error if the provided components would create an invalid cell.

H3Error constructCell(int res, int baseCellNumber, const int *digits, H3Index *out);

res: Resolution (0-15)
baseCellNumber: Base cell number (0-121)
digits: Array of indexing digits (0-6) of length res. Each digit digits[i] corresponds to the digit at resolution i+1. Can be NULL if res is 0.
out: Output parameter for the constructed cell

Returns 0 (E_SUCCESS) on success. Returns an error code on failure:

E_RES_DOMAIN: Invalid resolution (must be 0-15)
E_BASE_CELL_DOMAIN: Invalid base cell number (must be 0-121)
E_DIGIT_DOMAIN: Invalid digit value (must be 0-6)
E_DELETED_DIGIT: Attempted to use digit 1 in a pentagon base cell (deleted subsequence)

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java

long constructCell(int baseCellNumber, List<Integer> digits);
long constructCell(int baseCellNumber, List<Integer> digits, int res);
String constructCellAddress(int baseCellNumber, List<Integer> digits);
String constructCellAddress(int baseCellNumber, List<Integer> digits, int res);

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h3.constructCell(baseCellNumber, digits)
h3.constructCell(baseCellNumber, digits, res)

function example() {
  const baseCellNumber = 0;
  const res = 1;
  return h3.constructCell(baseCellNumber, [0], res);
}

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:::note

This function may not be available in all bindings.

:::

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:::note

This function may not be available in all bindings.

:::

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sql

h3_construct_cell(base_cell_number, digits)
h3_construct_cell(base_cell_number, digits, res)
h3_construct_cell_string(base_cell_number, digits)
h3_construct_cell_string(base_cell_number, digits, res)

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$ h3 constructCell --help
H3 4.3.0

    constructCell   Construct an H3 cell from resolution, base cell, and digits
    -h, --help      Show this help message.
    -r, --resolution <res>  Resolution, 0-15 inclusive. Inferred from digits if not provided. If provided, an error will be returned if there is a mismatch with the number of digits provided.
    -b, --baseCell <base>   Required. Base cell number, 0-121 inclusive.
    -d, --digits <d0,d1,...>        Comma-separated list of child digits (0-6) of length resolution.
    -f, --format <FMT>      'json' for "CELL"\n, 'newline' for CELL\n (Default: json)

bash

$ h3 constructCell -r 3 -b 73 -d 1,2,3
"839253fffffffff"

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:::note

When constructing a cell from a pentagon base cell, digit 1 (K_AXES_DIGIT) is not allowed to follow immediately after a sequence of 0 digits. In this case, the function will return E_DELETED_DIGIT.

:::

stringToH3

Converts the string representation to H3Index (uint64_t) representation.

H3Error stringToH3(const char *str, H3Index *out);

Returns 0 (E_SUCCESS) on success.

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java

long stringToH3(String h3Address);

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:::note

The H3 JavaScript binding supports only the string representation of an H3 index.

:::

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h3.str_to_int(h)

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h3.IndexFromString(str)

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sql

h3_string_to_h3(h)

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:::note

The H3 CLI supports only the string representation of an H3 index.

:::

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h3ToString

Converts the H3Index representation of the index to the string representation.

H3Error h3ToString(H3Index h, char *str, size_t sz);

str must be at least of length 17. Returns 0 (E_SUCCESS) on success.

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java

String h3ToString(long h3);

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:::note

The H3 JavaScript binding supports only the string representation of an H3 index.

:::

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h3.int_to_str(h)

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cell.String()

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sql

h3_h3_to_string(h)

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:::note

The H3 CLI supports only the string representation of an H3 index.

:::

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isValidCell

Returns non-zero if this is a valid H3 cell index.

int isValidCell(H3Index h);

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java

boolean isValidCell(long h3);
boolean isValidCell(String h3Address);

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h3.isValidCell(h)

function example() {
  const h = '85283473fffffff';
  return h3.isValidCell(h);
}

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h3.is_valid_cell(h)

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cell.IsValid()

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sql

h3_is_valid_cell(h)

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$ h3 isValidCell --help
h3: Checks if the provided H3 index is actually valid
H3 4.1.0

	isValidCell	Checks if the provided H3 index is actually valid
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell
	-f, --format <FMT>	'json' for true or false, 'numeric' for 1 or 0 (Default: json)

bash

$ h3 isValidCell -c 85283473fffffff
true

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isValidIndex

Returns non-zero if this is a valid H3 index for any mode (cell, directed edge, or vertex). That is, this returns true if any of the functions isValidCell, isValidDirectedEdge, or isValidVertex would return true.

int isValidIndex(H3Index h);

Returns 1 if the H3 index is valid for any supported type (cell, directed edge, or vertex), 0 otherwise.

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java

boolean isValidIndex(long h3);
boolean isValidIndex(String h3Address);

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:::note

This function may not be available in all bindings.

:::

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:::note

This function may not be available in all bindings.

:::

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:::note

This function may not be available in all bindings.

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sql

h3_is_valid_index(h)

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isResClassIII

Returns non-zero if this index has a resolution with Class III orientation.

int isResClassIII(H3Index h);

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java

boolean isResClassIII(long h3);
boolean isResClassIII(String h3Address);

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h3.isResClassIII(h)

function example() {
  const h = '85283473fffffff';
  return h3.isResClassIII(h);
}

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h3.is_res_class_III(h)

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cell.IsResClassIII()

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sql

h3_is_res_class_iii(h)

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$ h3 isResClassIII --help
h3: Checks if the provided H3 index has a Class III orientation
H3 4.1.0

	isResClassIII	Checks if the provided H3 index has a Class III orientation
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell
	-f, --format <FMT>	'json' for true or false, 'numeric' for 1 or 0 (Default: json)

bash

$ h3 isResClassIII -c 85283473fffffff
true

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isPentagon

Returns non-zero if this index represents a pentagonal cell.

int isPentagon(H3Index h);

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java

boolean isPentagon(long h3);
boolean isPentagon(String h3Address);

</TabItem> <TabItem value="javascript">

h3.isPentagon(h)

function example() {
  const h = '85283473fffffff';
  return h3.isPentagon(h);
}

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h3.is_pentagon(h)

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cell.IsPentagon()

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sql

h3_is_pentagon(h)

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$ h3 isPentagon --help
h3: Checks if the provided H3 index is a pentagon instead of a hexagon
H3 4.1.0

	isPentagon	Checks if the provided H3 index is a pentagon instead of a hexagon
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell
	-f, --format <FMT>	'json' for true or false, 'numeric' for 1 or 0 (Default: json)

bash

$ h3 isPentagon -c 85283473fffffff
false

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getIcosahedronFaces

Find all icosahedron faces intersected by a given H3 cell. Faces are represented as integers from 0-19, inclusive.

H3Error getIcosahedronFaces(H3Index h, int* out);

Face values are placed in the array out. out must be at least length of maxFaceCount(h). The array is sparse, and empty (no intersection) array values are represented by -1.

Returns 0 (E_SUCCESS) on success.

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java

Collection<Integer> getIcosahedronFaces(long h3);
Collection<Integer> getIcosahedronFaces(String h3Address);

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h3.getIcosahedronFaces(h)

function example() {
  const h = '85283473fffffff';
  return h3.getIcosahedronFaces(h);
}

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h3.get_icosahedron_faces(h)

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cell.IcosahedronFaces()

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sql

h3_get_icosahedron_faces(h)

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$ h3 getIcosahedronFaces --help
h3: Returns the icosahedron face numbers (0 - 19) that the H3 index intersects
H3 4.1.0

	getIcosahedronFaces	Returns the icosahedron face numbers (0 - 19) that the H3 index intersects
	-h, --help	Show this help message.
	-c, --cell <index>	Required. H3 Cell
	-f, --format <FMT>	'json' for [faceNum, ...], 'newline' for faceNum\n... (Default: json)

bash

$ h3 getIcosahedronFaces -c 85283473fffffff
[7]

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maxFaceCount

Returns the maximum number of icosahedron faces the given H3 index may intersect.

H3Error maxFaceCount(H3Index h3, int *out);

Returns 0 (E_SUCCESS) on success.

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:::note

This function exists for memory management and is not exposed.

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:::note

This function exists for memory management and is not exposed.

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:::note

This function exists for memory management and is not exposed.

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</TabItem> <TabItem value="go">

:::note

This function exists for memory management and is not exposed.

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</TabItem> <TabItem value="duckdb">

:::note

This function exists for memory management and is not exposed.

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:::note

This function exists for memory management and is not exposed.

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