Build & Test codecov License: Apache 2.0

H3 Dart

If you're developing Flutter application, use should use h3_flutter instead.

The package allows to use Uber's H3 library directly in your Dart application

The package uses h3_ffi and h3_web under the hood.

final h3Factory = const H3Factory();
const kIsWeb = identical(0, 0.0); // taken from
final h3 = kIsWeb 
  ? h3Factory.web() 
  : h3Factory.byPath('path/to/library.dll');
// Get hexagons in specified triangle.
final hexagons = h3.polyfill(
  resolution: 5,
  coordinates: [
    GeoCoord(20.4522, 54.7104),
    GeoCoord(37.6173, 55.7558),
    GeoCoord(39.7015, 47.2357),

There are also few methods ported from JS library Geojson2H3, to access them you should instantiate Geojson2H3 class using const Geojson2H3(h3). It uses package:geojson2h3 internally.


If you're developing Flutter application, use should use h3_flutter instead.


Get compiled h3 c library, depending on your platform it may have extension .so, .dll or any.

  • You can run scripts/ script, the compiled library will be at h3_ffi/c/h3lib/build/

  • You can compile it by yourself using C-code placed in c folder in this repository. It has small changes comparing to original Uber's code to make it more compatible with iOS and macOS versions of h3_flutter. This code is recompiled and used for testing everytime tests are launched, so it should work well.

  • You can compile original Uber's code, which also should work well, just make sure you use correct version -

Place your library somewhere and load it using final h3 = const H3Factory().byPath('path/to/library.dll');


Web version is built on top of h3-js, you have to import it.
Add next line to your index.html:

    <script defer src=""></script>

Note, main.dart.js import should go after this line

You can load the web version using final h3 = const H3Factory().web();