h3

<img align="right" src="https://uber.github.io/img/h3Logo-color.svg" alt="H3 Logo" width="200">

# H3: A Hexagonal Hierarchical Geospatial Indexing System

[![test-linux](https://github.com/uber/h3/workflows/test-linux/badge.svg)](https://github.com/uber/h3/actions)
[![test-macos](https://github.com/uber/h3/workflows/test-macos/badge.svg)](https://github.com/uber/h3/actions)
[![test-windows](https://github.com/uber/h3/workflows/test-windows/badge.svg)](https://github.com/uber/h3/actions)
[![test-website](https://github.com/uber/h3/workflows/test-website/badge.svg)](https://github.com/uber/h3/actions)
[![Coverage Status](https://coveralls.io/repos/github/uber/h3/badge.svg?branch=master)](https://coveralls.io/github/uber/h3?branch=master)
[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](LICENSE)

H3 is a geospatial indexing system using a hexagonal grid that can be (approximately) subdivided into finer and finer hexagonal grids, combining the benefits of a hexagonal grid with [S2](https://code.google.com/archive/p/s2-geometry-library/)'s hierarchical subdivisions.

Documentation is available at [https://h3geo.org/](https://h3geo.org/). Developer documentation in Markdown format is available under the [dev-docs](./dev-docs/) directory.

 * Post **bug reports or feature requests** to the [GitHub Issues page](https://github.com/uber/h3/issues)
 * Ask **questions** by posting to the [H3 tag on StackOverflow](https://stackoverflow.com/questions/tagged/h3)
 * There is also an [H3 Slack workspace](https://join.slack.com/t/h3-core/shared_invite/zt-g6u5r1hf-W_~uVJmfeiWtMQuBGc1NNg)

## Installing

We recommend using prebuilt bindings if they are available for your programming language. Bindings for [Java](https://github.com/uber/h3-java), [JavaScript](https://github.com/uber/h3-js), [Python](https://github.com/uber/h3-py), and [others](https://h3geo.org/docs/community/bindings) are available.

On macOS, you can install H3 using `brew`:
```
brew install h3
```
Otherwise, to build H3 from source, please see the following instructions.

### Building from source

Still here? To build the H3 C library, you'll need a C compiler (tested with `gcc` and `clang`), [CMake](https://cmake.org/), and [Make](https://www.gnu.org/software/make/). If you intend to contribute to H3, you must have [clang-format](https://clang.llvm.org/docs/ClangFormat.html) installed and we recommend installing [ccmake](https://cmake.org/cmake/help/v3.0/manual/ccmake.1.html) and [LCOV](https://github.com/linux-test-project/lcov) to configure the `cmake` arguments to build and run the tests and generate the code coverage report. We also recommend using `gcc` for the code coverage as some versions of `clang` generate annotations that aren't compatible with `lcov`. [Doxygen](https://www.doxygen.nl/index.html) is needed to build the API documentation.

#### Install build-time dependencies

* Alpine
```
# Installing the bare build requirements
apk add cmake make gcc libtool m