# PostgreSQL bindings for H3

This library provides PostgreSQL bindings for the [H3 Core Library](https://github.com/uber/h3). For API reference, please see the [H3 Documentation](https://uber.github.io/h3).

Developed in collaboration with [Scandinavian Highlands](http://www.scandinavian-highlands.com).

## Prerequisites

* PostgreSQL 9.6 or higher (*including server headers*). It might work with earlier versions, we have not tested earlier than 9.6.
* C compiler (e.g., gcc)
* GNU Make
* Git & CMake (for libh3)

## Quick Overview

If the prerequisites are met you can use the PGXN Client to download, build, and install, e.g.:

```
$ pgxn install h3
$ pgxn load -d mydb h3
$ psql -d mydb
=# SELECT h3_geo_to_h3(POINT('37.3615593,-122.0553238'), 5);
  h3_geo_to_h3   
-----------------
 85e35e73fffffff
(1 row)
```

## Usage

Generally, all functions have been renamed from camelCase in H3 to snake_case in SQL with an added `h3_` prefix (except when that would result in a double `h3_` prefix). For example `geoToH3` becomes `h3_geo_to_h3` and `h3ToChildren` becomes `h3_to_children`.

See [API reference](docs/api.md) for all provided functions.

## For developers

See [Development](docs/development.md).

## License

This project is released under the [Apache 2.0 License](LICENSE.md).