Dart Proximity Hash #

Proximity Hash generates a set of geohashes that cover a circular area, given the center coordinates and the radius. Geohash is a public domain geocode system which encodes a geographic location into a short string of letters and digits and is used as unique identifies and to represent point data in databases.

For example the point

25.6953° S, 54.4367° W

will covert to

6g3mc626.

Geohash #

Proximity hash also comes with a geohash library forked from dart_geohash since it was not being actively maintained.

import 'package:proximity_hash/geohash.dart';

Install #

To get this plugin, add proximity_hash as a dependency in your pubspec.yaml file. For example:

dependencies:
  proximity_hash: ^1.1.0

Usage #

To get all the geohashes within a radius of 5000 meters from the point 25.6953° S, 54.4367° W with precision 3 simply import the library and call createGeohashes(). The precision dictates how long and how many geohashes are returned. For example a precision of 3 returns geohahses of length 3.

import 'package:proximity_hash/proximity_hash.dart';

List<String> proximityGeohashes = createGeohashes(48.864716, 2.349014, 5000, 3);

// proximityGeohashes == ["u0d","u09"]

Performance #

Benchmark of createGeohashes for different precisions with radius 1000. Performance can become limiting starting at precision 9. Note that a larger radius will also decrease performance.

Issues #

Please file any issues, bugs or feature requests as an issue on our GitHub page.

Want to Contribute #

If you would like to contribute to the plugin (e.g. by improving the documentation, solving a bug or adding a cool new feature) submit a pull request.

Want to Support #

Based on proximityhash