H3 PostgreSQL

https://github.com/zachasme/h3-pg
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PostgreSQL bindings for H3, a hierarchical hexagonal geospatial indexing system
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### Install PGXN Client on Ubuntu with apt-get

Source: https://github.com/zachasme/h3-pg/blob/main/docs/pgxnclient.md

Use this command on Ubuntu to install the pgxnclient package via apt.

```bash
apt-get install pgxnclient
```

--------------------------------

### Quick Overview: Install, Load, and Query h3

Source: https://github.com/zachasme/h3-pg/blob/main/README.md

Use the PGXN client to install and load the h3 extension, then run a sample query converting a latitude/longitude point to an H3 cell at resolution 5. The output shows the resulting cell ID '85e35e73fffffff'. You can install a specific version using 'pgxn install h3=3.7.2' and 'pgxn load h3=3.7.2'.

```shell
$ pgxn install h3
$ pgxn load h3
$ psql
=# SELECT h3_latlng_to_cell(POINT('37.3615593,-122.0553238'), 5);
  h3_latlng_to_cell
-----------------
 85e35e73fffffff
(1 row)
```

--------------------------------

### Install PGXN Client on macOS with brew

Source: https://github.com/zachasme/h3-pg/blob/main/docs/pgxnclient.md

Use this command on macOS to install pgxnclient via Homebrew.

```bash
brew install pgxnclient
```

--------------------------------

### Install h3-pg on Debian/Ubuntu

Source: https://github.com/zachasme/h3-pg/blob/main/README.md

Install the h3-pg package for PostgreSQL 16 on Debian/Ubuntu systems. Replace '16' with your PostgreSQL version. Requires PostgreSQL installed via PGDG repositories.

```shell
sudo apt install postgresql-16-h3
```

--------------------------------

### Build h3-pg with CMake

Source: https://github.com/zachasme/h3-pg/blob/main/README.md

Generate the native build system, build the extension(s), and install them. The install step might require sudo. This is an alternative to using the PGXN client.

```bash
# Generate native build system
cmake -B build -DCMAKE_BUILD_TYPE=Release

# Build extension(s)
cmake --build build

# Install extensions (might require sudo)
cmake --install build --component h3-pg
```

--------------------------------

### Install h3-pg on Red Hat Derivatives

Source: https://github.com/zachasme/h3-pg/blob/main/README.md

Install the h3-pg package for PostgreSQL 16 on Rocky/EL 8+ or Fedora 37+. Replace '16' with your PostgreSQL version. Requires PostgreSQL installed via PGDG repositories.

```shell
sudo yum install h3-pg_16
```

--------------------------------

### h3_get_extension_version() ⇒ text

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns the currently installed version of the h3-pg extension.

```APIDOC
## h3_get_extension_version() ⇒ text

### Description
Get the currently installed version of the extension.

### Since
v1.0.0

### Function
h3_get_extension_version()

### Parameters
None

### Returns
- **text** - The installed extension version.
```

--------------------------------

### SQL: Summarize raster classes per H3 cell with JSON and fraction

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Query that aggregates raster class summaries per H3 cell and value, then combines them into a JSON object with a fraction of pixels per class. Uses h3_raster_class_summary, h3_raster_class_summary_item_agg, and h3_raster_class_summary_item_to_jsonb. The output shows example rows with class_1 and class_2 fields.

```sql
WITH
    summary AS (
        -- get aggregated summary for each H3 index/value pair
        SELECT h3, val, h3_raster_class_summary_item_agg(summary) AS item
        FROM
            rasters,
            h3_raster_class_summary(rast, 8)
        GROUP BY 1, 2),
    summary_total AS (
        -- add total number of pixels per H3 cell
        SELECT h3, val, item, sum((item).count) OVER (PARTITION BY h3) AS total
        FROM summary)
SELECT
    h3,
    jsonb_object_agg(
        concat('class_', val::text),
        h3_raster_class_summary_item_to_jsonb(item)                 -- val, count, area
            || jsonb_build_object('fraction', (item).count / total) -- add fraction value
        ORDER BY val
    ) AS summary
FROM summary_total
GROUP BY 1;
      h3        |                                                                            summary
----------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------
88194e6f3bfffff | {"class_1": {"area": 75855.5748, "count": 46, "value": 1, "fraction": 0.4509}, "class_2": {"area": 92345.9171, "count": 56, "value": 2, "fraction": 0.5490}}
88194e6f37fffff | {"class_1": {"area": 255600.3064, "count": 155, "value": 1, "fraction": 0.5}, "class_2": {"area": 255600.3064, "count": 155, "value": 2, "fraction": 0.5}}
88194e6f33fffff | {"class_1": {"area": 336402.9840, "count": 204, "value": 1, "fraction": 0.5125}, "class_2": {"area": 319912.6416, "count": 194, "value": 2, "fraction": 0.4874}}
<...>
```

--------------------------------

### h3_raster_class_summary_item_to_jsonb(item h3_raster_class_summary_item) ⇒ jsonb

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Converts a raster summary item to a JSONB object. Example output: {"count": 10, "value": 2, "area": 16490.3423}.

```APIDOC
## h3_raster_class_summary_item_to_jsonb(item h3_raster_class_summary_item) ⇒ jsonb

### Description
Converts a raster summary item to a JSONB object. Example output: `{"count": 10, "value": 2, "area": 16490.3423}`.

### Since
v4.1.1

### Parameters
- **item** (`h3_raster_class_summary_item`) - Required - The raster summary item to convert.

### Returns
- **jsonb** - The JSONB representation of the summary item.
```

--------------------------------

### CREATE EXTENSION h3

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Creates the core H3 bindings extension with indexing, traversal, hierarchy, inspection, and the <-> operator. No PostGIS dependency.

```APIDOC
## CREATE EXTENSION h3

### Description
Creates the core H3 bindings extension with indexing, traversal, hierarchy, inspection, and the <-> operator. No PostGIS dependency.

### Method
CREATE EXTENSION

### Endpoint
N/A

### Parameters
No parameters.

### Request Example
CREATE EXTENSION h3;

### Response
#### Success Response
Extension created successfully.

#### Response Example
CREATE EXTENSION
```

--------------------------------

### Create SP-GiST index with h3index_ops_experimental

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Adds an SP-GiST index using the experimental operator class. The commented line shows the general syntax; the active line creates an index named spgist_idx on the h3_data table's hex column.

```sql
-- CREATE INDEX [indexname] ON [tablename] USING spgist([column] h3index_ops_experimental);
CREATE INDEX spgist_idx ON h3_data USING spgist(hex h3index_ops_experimental);
```

--------------------------------

### h3_vertex_to_latlng(vertex h3index) ⇒ point

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Get the geocoordinates of an H3 vertex. Available since v4.2.3.

```APIDOC
## h3_vertex_to_latlng(vertex h3index) ⇒ point

### Description
Get the geocoordinates of an H3 vertex.

### Function Signature
h3_vertex_to_latlng(vertex `h3index`) ⇒ `point`

### Parameters
- **vertex** (`h3index`) - Required - The vertex H3 index.

### Returns
- `point` - The geocoordinates of the vertex.

### Since
v4.2.3
```

--------------------------------

### SP-GiST operator class (experimental)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Add an SP-GiST index using the h3index_ops_experimental operator class. This is an experimental feature and may change in future versions.

```APIDOC
## SP-GiST operator class (experimental)

### Description
Add an SP-GiST index using the `h3index_ops_experimental` operator class. This is an experimental feature and may change in future versions.

### Usage
```sql
-- CREATE INDEX [indexname] ON [tablename] USING spgist([column] h3index_ops_experimental);
CREATE INDEX spgist_idx ON h3_data USING spgist(hex h3index_ops_experimental);
```

### Since
Experimental
```

--------------------------------

### SQL: Find most frequent raster class per H3 cell

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Query that returns the area of the most frequent value per H3 cell using DISTINCT ON and ordering by count descending. Uses h3_raster_class_summary and h3_raster_class_summary_item_agg. Output shows example rows with h3, val, and area.

```sql
SELECT DISTINCT ON (h3)
    h3, val, (item).area
FROM (
    SELECT
        h3, val, h3_raster_class_summary_item_agg(summary) AS item
    FROM
        rasters,
        h3_raster_class_summary(rast, 8)
    GROUP BY 1, 2
) t
ORDER BY h3, (item).count DESC;
       h3        | val |        area
-----------------+-----+--------------------
 88194e6f3bfffff |   5 | 23238.699360251427
 88194e6f37fffff |   9 |  60863.26022922993
 88194e6f33fffff |   8 |  76355.72646939754
<...>
```

--------------------------------

### h3_get_resolution_from_tile_zoom(z integer, [max_h3_resolution integer = 15], min_h3_resolution integer, [hex_edge_pixels integer = 44], [tile_size integer = 512]) ⇒ integer

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns the optimal H3 resolution for a specified XYZ tile zoom level, based on hexagon size in pixels and resolution limits.

```APIDOC
## h3_get_resolution_from_tile_zoom(z integer, [max_h3_resolution integer = 15], min_h3_resolution integer, [hex_edge_pixels integer = 44], [tile_size integer = 512]) ⇒ integer

### Description
Returns the optimal H3 resolution for a specified XYZ tile zoom level, based on hexagon size in pixels and resolution limits.

### Since
v4.2.3

### Function
h3_get_resolution_from_tile_zoom(z integer, [max_h3_resolution integer = 15], min_h3_resolution integer, [hex_edge_pixels integer = 44], [tile_size integer = 512])

### Parameters
- **z** (integer) - Required - The XYZ tile zoom level.
- **max_h3_resolution** (integer) - Optional, default 15 - The maximum H3 resolution.
- **min_h3_resolution** (integer) - Required - The minimum H3 resolution.
- **hex_edge_pixels** (integer) - Optional, default 44 - The hexagon edge size in pixels.
- **tile_size** (integer) - Optional, default 512 - The tile size in pixels.

### Returns
- **integer** - The optimal H3 resolution.
```

--------------------------------

### CREATE EXTENSION h3_postgis

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Creates the PostGIS integration extension with geometry/geography casts, @ operator, polygon fill, and raster helpers. Requires postgis and optionally postgis_raster.

```APIDOC
## CREATE EXTENSION h3_postgis

### Description
Creates the PostGIS integration extension with geometry/geography casts, @ operator, polygon fill, and raster helpers. Requires postgis and optionally postgis_raster.

### Method
CREATE EXTENSION

### Endpoint
N/A

### Parameters
No parameters.

### Request Example
CREATE EXTENSION h3_postgis;

### Response
#### Success Response
Extension created successfully.

#### Response Example
CREATE EXTENSION
```

--------------------------------

### h3_raster_class_summary(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns a summary item for each H3 cell and value for a given band. Attempts to select an appropriate method based on number of pixels per H3 cell.

```APIDOC
## h3_raster_class_summary(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

### Description
Returns a summary item for each H3 cell and value for a given band. Attempts to select an appropriate method based on number of pixels per H3 cell.

### Since
v4.1.1

### Parameters
- **rast** (`raster`) - Required - The input raster.
- **resolution** (`integer`) - Required - H3 resolution.
- **nband** (`integer`) - Optional - Band number, defaults to 1.

### Returns
- **TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)** - A table with H3 index, pixel value, and summary item.
```

--------------------------------

### Operator: geometry @ integer

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Indexes a geometry at the specified resolution. Available since v4.1.3.

```APIDOC
## Operator: geometry @ integer

### Description
Indexes a geometry at the specified resolution.

### Parameters
- **geometry** (geometry) - Required - Input geometry
- **integer** (integer) - Required - H3 resolution

### Returns
h3index - H3 index of the geometry at the given resolution

### Since
v4.1.3
```

--------------------------------

### h3_polygon_to_cells_experimental(multi geometry, resolution integer, [containment_mode text = center]) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Experimental version of h3_polygon_to_cells with a containment mode parameter. Available since v4.2.0.

```APIDOC
## h3_polygon_to_cells_experimental(multi geometry, resolution integer, [containment_mode text = center]) ⇒ SETOF h3index

### Description
Experimental version of h3_polygon_to_cells with a containment mode parameter.

### Parameters
- **multi** (geometry) - Required - Input polygon geometry
- **resolution** (integer) - Required - H3 resolution (0-15)
- **containment_mode** (text) - Optional - Default: center - Containment mode (e.g., 'center')

### Returns
SETOF h3index - Set of H3 cells covering the polygon

### Since
v4.2.0
```

--------------------------------

### h3_grid_disk(origin h3index, [k integer = 1]) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Produces indices within k distance of the origin index.

```APIDOC
## h3_grid_disk(origin `h3index`, [k `integer` = 1]) ⇒ SETOF `h3index`

### Description
Produces indices within "k" distance of the origin index.

### Function Signature
`h3_grid_disk(origin h3index, [k integer = 1])`

### Parameters
- **origin** (h3index) - Required - The origin H3 index.
- **k** (integer) - Optional, default 1 - The distance (number of rings) to include.

### Returns
- **SETOF h3index** - Set of H3 indices within k distance of the origin.

### Since
v4.0.0
```

--------------------------------

### Aggregate raster summary stats by H3 index with h3_raster_summary and h3_raster_summary_stats_agg

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Query that computes per-H3-cell summary statistics from a raster table using h3_raster_summary at resolution 8, then aggregates the stats across rasters with h3_raster_summary_stats_agg. The output shows the resulting columns: h3, count, sum, mean, stddev, min, max. The output is truncated with <...> in the source.

```sql
SELECT
    (summary).h3 AS h3,
    (h3_raster_summary_stats_agg((summary).stats)).*
FROM (
    SELECT h3_raster_summary(rast, 8) AS summary
    FROM rasters
) t
GROUP BY 1;
```

```text
       h3        | count |        sum         |        mean         |       stddev       |  min  |       max
-----------------+-------+--------------------+---------------------+--------------------+-------+------------------
 882d638189fffff |    10 |  4.607657432556152 | 0.46076574325561526 | 1.3822972297668457 |     0 | 4.607657432556152
 882d64c4d1fffff |    10 | 3.6940908953547478 |  0.3694090895354748 |  1.099336879464068 |     0 | 3.667332887649536
 882d607431fffff |    11 |  6.219290263950825 |  0.5653900239955295 | 1.7624673707119065 |     0 | 6.13831996917724
<...>
```

--------------------------------

### h3_polygon_to_cells_experimental(multi geography, resolution integer, [containment_mode text = center]) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Experimental version of h3_polygon_to_cells for geography with a containment mode parameter. Available since v4.2.0.

```APIDOC
## h3_polygon_to_cells_experimental(multi geography, resolution integer, [containment_mode text = center]) ⇒ SETOF h3index

### Description
Experimental version of h3_polygon_to_cells for geography with a containment mode parameter.

### Parameters
- **multi** (geography) - Required - Input polygon geography
- **resolution** (integer) - Required - H3 resolution (0-15)
- **containment_mode** (text) - Optional - Default: center - Containment mode (e.g., 'center')

### Returns
SETOF h3index - Set of H3 cells covering the polygon

### Since
v4.2.0
```

--------------------------------

### h3_local_ij_to_cell(origin h3index, coord point) ⇒ h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Produces an H3 index from local IJ coordinates anchored by an origin.

```APIDOC
## h3_local_ij_to_cell(origin `h3index`, coord `point`) ⇒ `h3index`

### Description
Produces an H3 index from local IJ coordinates anchored by an origin.

### Function Signature
`h3_local_ij_to_cell(origin h3index, coord point)`

### Parameters
- **origin** (h3index) - Required - The origin H3 index.
- **coord** (point) - Required - The local IJ coordinates.

### Returns
- **h3index** - The H3 index corresponding to the given local IJ coordinates.

### Since
v0.2.0
```

--------------------------------

### h3_raster_class_summary_subpixel(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns a summary item for each H3 cell and value for a given band. Assumes H3 cell is smaller than a pixel. Finds corresponding pixel for each H3 cell in raster.

```APIDOC
## h3_raster_class_summary_subpixel(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

### Description
Returns a summary item for each H3 cell and value for a given band. Assumes H3 cell is smaller than a pixel. Finds corresponding pixel for each H3 cell in raster.

### Since
v4.1.1

### Parameters
- **rast** (`raster`) - Required - The input raster.
- **resolution** (`integer`) - Required - H3 resolution.
- **nband** (`integer`) - Optional - Band number, defaults to 1.

### Returns
- **TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)** - A table with H3 index, pixel value, and summary item.
```

--------------------------------

### h3_raster_class_summary_centroids(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns a summary item for each H3 cell and value for a given band. Finds the corresponding H3 cell for each pixel, then groups by H3 and value.

```APIDOC
## h3_raster_class_summary_centroids(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

### Description
Returns a summary item for each H3 cell and value for a given band. Finds the corresponding H3 cell for each pixel, then groups by H3 and value.

### Since
v4.1.1

### Parameters
- **rast** (`raster`) - Required - The input raster.
- **resolution** (`integer`) - Required - H3 resolution.
- **nband** (`integer`) - Optional - Band number, defaults to 1.

### Returns
- **TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)** - A table with H3 index, pixel value, and summary item.
```

--------------------------------

### h3_raster_class_summary_clip(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns a summary item for each H3 cell and value for a given band. Clips the raster by H3 cell geometries and processes each part separately.

```APIDOC
## h3_raster_class_summary_clip(rast raster, resolution integer, [nband integer = 1]) ⇒ TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)

### Description
Returns a summary item for each H3 cell and value for a given band. Clips the raster by H3 cell geometries and processes each part separately.

### Since
v4.1.1

### Parameters
- **rast** (`raster`) - Required - The input raster.
- **resolution** (`integer`) - Required - H3 resolution.
- **nband** (`integer`) - Optional - Band number, defaults to 1.

### Returns
- **TABLE (h3 h3index, val integer, summary h3_raster_class_summary_item)** - A table with H3 index, pixel value, and summary item.
```

--------------------------------

### h3_get_pentagons(resolution integer) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns all the pentagon H3 indexes at the specified resolution. Available since v4.0.0.

```APIDOC
## h3_get_pentagons(resolution integer) ⇒ SETOF h3index

### Description
All the pentagon H3 indexes at the specified resolution.

### Function Signature
`h3_get_pentagons(resolution integer)`

### Parameters
- **resolution** (integer) - Required - H3 resolution.

### Return Type
`SETOF h3index`

### Since
v4.0.0
```

--------------------------------

### h3_grid_disk_distances(origin h3index, [k integer = 1], OUT index h3index, OUT distance int) ⇒ SETOF record

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Produces indices within k distance of the origin index paired with their distance to the origin.

```APIDOC
## h3_grid_disk_distances(origin `h3index`, [k `integer` = 1], OUT index `h3index`, OUT distance `int`) ⇒ SETOF `record`

### Description
Produces indices within "k" distance of the origin index paired with their distance to the origin.

### Function Signature
`h3_grid_disk_distances(origin h3index, [k integer = 1], OUT index h3index, OUT distance int)`

### Parameters
- **origin** (h3index) - Required - The origin H3 index.
- **k** (integer) - Optional, default 1 - The distance (number of rings) to include.
- **index** (h3index) - Output - The H3 index.
- **distance** (int) - Output - The distance from the origin.

### Returns
- **SETOF record** - Set of records containing index and distance.

### Since
v4.0.0
```

--------------------------------

### h3_pg_migrate_pass_by_reference(h3index) ⇒ h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Migrates an h3index from pass-by-reference to pass-by-value.

```APIDOC
## h3_pg_migrate_pass_by_reference(h3index) ⇒ h3index

### Description
Migrate h3index from pass-by-reference to pass-by-value.

### Since
v4.1.0

### Function
h3_pg_migrate_pass_by_reference(h3index)

### Parameters
- **h3index** (h3index) - Required - The H3 index to migrate.

### Returns
- **h3index** - The migrated H3 index.
```

--------------------------------

### h3_polygon_to_cells_experimental(exterior polygon, holes polygon[], [resolution integer = 1], [containment_mode text = center]) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Takes an exterior polygon and optional holes, and returns the set of hexagons that best fit the structure. Available since v4.2.0.

```APIDOC
## h3_polygon_to_cells_experimental(exterior `polygon`, holes `polygon[]`, [resolution `integer` = 1], [containment_mode `text` = center]) ⇒ SETOF `h3index`

### Description
Takes an exterior polygon [and a set of hole polygon] and returns the set of hexagons that best fit the structure.

### Parameters
- **exterior** (`polygon`) - Required - The exterior polygon.
- **holes** (`polygon[]`) - Required - Array of hole polygons.
- **resolution** (`integer`) - Optional - Defaults to 1. The H3 resolution.
- **containment_mode** (`text`) - Optional - Defaults to 'center'. The containment mode.

### Returns
SETOF `h3index` - The set of hexagons that best fit the structure.

### Since
v4.2.0
```

--------------------------------

### h3_polygon_to_cells(geometry, resolution)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Fills a polygon with H3 cells at the given resolution. Available in h3_postgis.

```APIDOC
## h3_polygon_to_cells(geometry, resolution)

### Description
Fills a polygon with H3 cells at the given resolution. Available in h3_postgis.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **geometry** (geometry) - Required - The polygon to fill.
- **resolution** (integer) - Required - The H3 resolution to use.

### Request Example
SELECT h3_polygon_to_cells(geom, 9) FROM polygons;

### Response
#### Success Response
Returns a SETOF h3index.

#### Response Example
{ '8928308280fffff', '8928308280fffff' }
```

--------------------------------

### Operator: geography @ integer

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Indexes a geography at the specified resolution. Available since v4.1.3.

```APIDOC
## Operator: geography @ integer

### Description
Indexes a geography at the specified resolution.

### Parameters
- **geography** (geography) - Required - Input geography
- **integer** (integer) - Required - H3 resolution

### Returns
h3index - H3 index of the geography at the given resolution

### Since
v4.1.3
```

--------------------------------

### h3_cell_to_children_slow(index h3index, resolution integer) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Slower version of H3ToChildren but allocates less memory.

```APIDOC
## h3_cell_to_children_slow(index h3index, resolution integer) ⇒ SETOF h3index

### Description
Slower version of H3ToChildren but allocates less memory.

### Function Signature
`h3_cell_to_children_slow(index h3index, resolution integer) ⇒ SETOF h3index`

### Parameters
- **index** (`h3index`) - The H3 cell index.
- **resolution** (`integer`) - The target resolution for the children cells.

### Returns
- SETOF `h3index` - The set of child cell indices.

### Since
v4.0.0
```

--------------------------------

### h3_cell_to_children_slow(index h3index) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Slower version of H3ToChildren but allocates less memory.

```APIDOC
## h3_cell_to_children_slow(index h3index) ⇒ SETOF h3index

### Description
Slower version of H3ToChildren but allocates less memory.

### Function Signature
`h3_cell_to_children_slow(index h3index) ⇒ SETOF h3index`

### Parameters
- **index** (`h3index`) - The H3 cell index.

### Returns
- SETOF `h3index` - The set of child cell indices.
```

--------------------------------

### bigint :: h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Converts a bigint to an H3 index.

```APIDOC
## bigint :: h3index

### Description
Convert bigint to H3 index.

### Cast
bigint :: h3index

### Parameters
- **bigint** (bigint) - Required - The bigint value to convert.

### Returns
- **h3index** - The resulting H3 index.
```

--------------------------------

### h3_cell_to_boundary_geometry(h3index)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Returns the boundary of an H3 cell as a polygon with SRID 4326, splitting at the antimeridian. Available in h3_postgis.

```APIDOC
## h3_cell_to_boundary_geometry(h3index)

### Description
Returns the boundary of an H3 cell as a polygon with SRID 4326, splitting at the antimeridian. Available in h3_postgis.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **h3index** (h3index) - Required - The H3 cell to get the boundary for.

### Request Example
SELECT h3_cell_to_boundary_geometry(h3) FROM h3_table;

### Response
#### Success Response
Returns a geometry polygon with SRID 4326.

#### Response Example
POLYGON((-122.4194 37.7749, ...))
```

--------------------------------

### h3_grid_path_cells(origin h3index, destination h3index) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Given two H3 indexes, returns the line of indexes between them (inclusive). May fail for very distant indexes or across pentagons.

```APIDOC
## h3_grid_path_cells(origin `h3index`, destination `h3index`) ⇒ SETOF `h3index`

### Description
Given two H3 indexes, return the line of indexes between them (inclusive).
This function may fail to find the line between two indexes, for
example if they are very far apart. It may also fail when finding
distances for indexes on opposite sides of a pentagon.

### Function Signature
`h3_grid_path_cells(origin h3index, destination h3index)`

### Parameters
- **origin** (h3index) - Required - The starting H3 index.
- **destination** (h3index) - Required - The ending H3 index.

### Returns
- **SETOF h3index** - Set of H3 indices forming the path between origin and destination (inclusive).

### See Also
- `h3_grid_path_cells_recursive(h3index, h3index)`

### Since
v4.0.0
```

--------------------------------

### h3_get_icosahedron_faces(h3index) ⇒ integer[]

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Finds all icosahedron faces intersected by a given H3 index.

```APIDOC
## h3_get_icosahedron_faces(`h3index`) ⇒ `integer[]`

### Description
Find all icosahedron faces intersected by a given H3 index.

### Function Signature
`h3_get_icosahedron_faces(h3index)`

### Parameters
- **h3index** (h3index) - Required - The H3 index to inspect.

### Returns
- **integer[]** - Array of icosahedron face numbers intersected by the index.

### Since
v4.0.0
```

--------------------------------

### h3_polygon_to_cells(geography, resolution)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Fills a polygon with H3 cells at the given resolution. Available in h3_postgis.

```APIDOC
## h3_polygon_to_cells(geography, resolution)

### Description
Fills a polygon with H3 cells at the given resolution. Available in h3_postgis.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **geography** (geography) - Required - The polygon to fill.
- **resolution** (integer) - Required - The H3 resolution to use.

### Request Example
SELECT h3_polygon_to_cells(geog, 9) FROM polygons;

### Response
#### Success Response
Returns a SETOF h3index.

#### Response Example
{ '8928308280fffff', '8928308280fffff' }
```

--------------------------------

### h3_raster_summary

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns summary statistics for each H3 cell in a raster for a given band. Attempts to select an appropriate method based on the number of pixels per H3 cell. Available since v4.1.1.

```APIDOC
## h3_raster_summary

### Description
Returns `h3_raster_summary_stats` for each H3 cell in a raster for a given band. Attempts to select an appropriate method based on the number of pixels per H3 cell.

### Function Signature
`h3_raster_summary(rast raster, resolution integer, [nband integer = 1])` returns `TABLE (h3 h3index, stats h3_raster_summary_stats)`

### Parameters
- **rast** (raster) - Required - The input raster.
- **resolution** (integer) - Required - The H3 resolution to use.
- **nband** (integer) - Optional, default 1 - The band number to process.

### Returns
- **h3** (h3index) - The H3 cell index.
- **stats** (h3_raster_summary_stats) - Summary statistics for the cell.

### Availability
Since v4.1.1
```

--------------------------------

### h3_raster_summary(raster, resolution, [band])

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Computes per-cell statistics (count, sum, mean, stddev, min, max) for a raster at the given resolution. Available in h3_postgis, requires postgis_raster.

```APIDOC
## h3_raster_summary(raster, resolution, [band])

### Description
Computes per-cell statistics (count, sum, mean, stddev, min, max) for a raster at the given resolution. Available in h3_postgis, requires postgis_raster.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **raster** (raster) - Required - The raster to analyze.
- **resolution** (integer) - Required - The H3 resolution to use.
- **band** (integer) - Optional - The band number to analyze. Defaults to 1.

### Request Example
SELECT h3_raster_summary(rast, 9) FROM rasters;

### Response
#### Success Response
Returns a table with columns: h3index, count, sum, mean, stddev, min, max.

#### Response Example
h3index | count | sum | mean | stddev | min | max
---------+-------+-----+------+--------+-----+-----
8928308280fffff | 10 | 100 | 10 | 2.5 | 5 | 15
```

--------------------------------

### h3_get_resolution(h3index) ⇒ integer

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns the resolution of the given H3 index.

```APIDOC
## h3_get_resolution(`h3index`) ⇒ `integer`

### Description
Returns the resolution of the index.

### Function Signature
`h3_get_resolution(h3index)`

### Parameters
- **h3index** (h3index) - Required - The H3 index to inspect.

### Returns
- **integer** - The resolution of the index.

### Since
v1.0.0
```

--------------------------------

### h3_polygon_to_cells

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Fills a polygon with H3 cells. Replaces h3_polyfill in v4.

```APIDOC
## h3_polygon_to_cells

### Description
Fills a polygon with H3 cells. Replaces h3_polyfill in v4.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **geometry** (geometry) - Required - The polygon to fill.
- **resolution** (integer) - Required - The H3 resolution.

### Request Example
SELECT h3_polygon_to_cells(geom, 9) FROM polygons;

### Response
#### Success Response
Returns a SETOF h3index.

#### Response Example
{ '8928308280fffff', '8928308280fffff', ... }
```

--------------------------------

### h3_raster_class_summary*(...)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Computes discrete class counts per cell. Available in h3_postgis, requires postgis_raster.

```APIDOC
## h3_raster_class_summary*(...)

### Description
Computes discrete class counts per cell. Available in h3_postgis, requires postgis_raster.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **raster** (raster) - Required - The raster to analyze.
- **resolution** (integer) - Required - The H3 resolution to use.
- **band** (integer) - Optional - The band number to analyze.

### Request Example
SELECT h3_raster_class_summary(rast, 9) FROM rasters;

### Response
#### Success Response
Returns per-cell class counts.

#### Response Example
h3index | class | count
---------+-------+------
8928308280fffff | 1 | 10
```

--------------------------------

### h3_grid_disk

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Returns the set of cells within a k-ring distance. Replaces h3_k_ring in v4.

```APIDOC
## h3_grid_disk

### Description
Returns the set of cells within a k-ring distance. Replaces h3_k_ring in v4.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **h3index** (h3index) - Required - The origin cell.
- **k** (integer) - Required - Ring distance.

### Request Example
SELECT h3_grid_disk('8928308280fffff', 1);

### Response
#### Success Response
Returns a SETOF h3index.

#### Response Example
{ '8928308280fffff', '8928308280fffff', ... }
```

--------------------------------

### h3_raster_summary_subpixel

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Returns summary statistics for each H3 cell in a raster for a given band. Assumes H3 cell is smaller than a pixel and finds the corresponding pixel for each H3 cell. Available since v4.1.1.

```APIDOC
## h3_raster_summary_subpixel

### Description
Returns `h3_raster_summary_stats` for each H3 cell in a raster for a given band. Assumes H3 cell is smaller than a pixel and finds the corresponding pixel for each H3 cell in the raster.

### Function Signature
`h3_raster_summary_subpixel(rast raster, resolution integer, [nband integer = 1])` returns `TABLE (h3 h3index, stats h3_raster_summary_stats)`

### Parameters
- **rast** (raster) - Required - The input raster.
- **resolution** (integer) - Required - The H3 resolution to use.
- **nband** (integer) - Optional, default 1 - The band number to process.

### Returns
- **h3** (h3index) - The H3 cell index.
- **stats** (h3_raster_summary_stats) - Summary statistics for the cell.

### Availability
Since v4.1.1
```

--------------------------------

### h3_cell_to_local_ij(origin h3index, index h3index) ⇒ point

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Produces local IJ coordinates for an H3 index anchored by an origin.

```APIDOC
## h3_cell_to_local_ij(origin `h3index`, index `h3index`) ⇒ `point`

### Description
Produces local IJ coordinates for an H3 index anchored by an origin.

### Function Signature
`h3_cell_to_local_ij(origin h3index, index h3index)`

### Parameters
- **origin** (h3index) - Required - The origin H3 index.
- **index** (h3index) - Required - The H3 index to convert.

### Returns
- **point** - Local IJ coordinates as a point.

### Since
v0.2.0
```

--------------------------------

### h3_raster_summary_clip(...)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Clips raster by cell boundaries. Available in h3_postgis, requires postgis_raster.

```APIDOC
## h3_raster_summary_clip(...)

### Description
Clips raster by cell boundaries. Available in h3_postgis, requires postgis_raster.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **raster** (raster) - Required - The raster to clip.
- **resolution** (integer) - Required - The H3 resolution to use.
- **band** (integer) - Optional - The band number to analyze.

### Request Example
SELECT h3_raster_summary_clip(rast, 9) FROM rasters;

### Response
#### Success Response
Returns per-cell statistics clipped to cell boundaries.

#### Response Example
h3index | count | sum | mean | stddev | min | max
---------+-------+-----+------+--------+-----+-----
8928308280fffff | 10 | 100 | 10 | 2.5 | 5 | 15
```

--------------------------------

### h3_cell_to_boundary_geography(h3index)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Returns the boundary of an H3 cell as a geography polygon, splitting at the antimeridian. Available in h3_postgis.

```APIDOC
## h3_cell_to_boundary_geography(h3index)

### Description
Returns the boundary of an H3 cell as a geography polygon, splitting at the antimeridian. Available in h3_postgis.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **h3index** (h3index) - Required - The H3 cell to get the boundary for.

### Request Example
SELECT h3_cell_to_boundary_geography(h3) FROM h3_table;

### Response
#### Success Response
Returns a geography polygon.

#### Response Example
POLYGON((-122.4194 37.7749, ...))
```

--------------------------------

### h3_raster_summary_subpixel(...)

Source: https://github.com/zachasme/h3-pg/blob/main/docs/SKILL.md

Computes statistics for cells smaller than pixels. Available in h3_postgis, requires postgis_raster.

```APIDOC
## h3_raster_summary_subpixel(...)

### Description
Computes statistics for cells smaller than pixels. Available in h3_postgis, requires postgis_raster.

### Method
FUNCTION

### Endpoint
N/A

### Parameters
#### Input
- **raster** (raster) - Required - The raster to analyze.
- **resolution** (integer) - Required - The H3 resolution to use.
- **band** (integer) - Optional - The band number to analyze.

### Request Example
SELECT h3_raster_summary_subpixel(rast, 9) FROM rasters;

### Response
#### Success Response
Returns per-cell statistics for subpixel cells.

#### Response Example
h3index | count | sum | mean | stddev | min | max
---------+-------+-----+------+--------+-----+-----
8928308280fffff | 10 | 100 | 10 | 2.5 | 5 | 15
```

--------------------------------

### h3_polygon_to_cells(exterior polygon, holes polygon[], [resolution integer = 1]) ⇒ SETOF h3index

Source: https://github.com/zachasme/h3-pg/blob/main/docs/api.md

Takes an exterior polygon and optional holes, and returns the set of hexagons that best fit the structure. Available since v4.0.0.

```APIDOC
## h3_polygon_to_cells(exterior `polygon`, holes `polygon[]`, [resolution `integer` = 1]) ⇒ SETOF `h3index`

### Description
Takes an exterior polygon [and a set of hole polygon] and returns the set of hexagons that best fit the structure.

### Parameters
- **exterior** (`polygon`) - Required - The exterior polygon.
- **holes** (`polygon[]`) - Required - Array of hole polygons.
- **resolution** (`integer`) - Optional - Defaults to 1. The H3 resolution.

### Returns
SETOF `h3index` - The set of hexagons that best fit the structure.

### Since
v4.0.0
```
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