GeohashTree

Dart GeohashTree

GeohashTree is a tree implimentation to speed up spacial queries through geohash indexing. This is useful for dynamically querying small selections of locations in a certain radius for example to display in a map as the user scrolls. The GeohashTree can have a variable depth with the default set at 9. This corresponds to a geohash of precision or length 9.

Install

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

dependencies:
  geohashtree: ^1.0.2

Usage

It is possible to add spatial based values to the tree with a geohash or directly with lat lng coordinates.

import 'package:geohashtree/geohashtree.dart';

GeohashTree<String> tree = GeohashTree<String>(); 
tree.add("6g3mc", "iguazu"); 
tree.addLatLng(-25.686667, -54.444722, "also iguazu");

To get all the coordinates in a tree within a radius of 5000 meters from the point 25.6953° S, 54.4367° W use getGeohashesByProximity(). The precision parameter dictates how specific the geohash match should be. Precision 5 return matches of geohash of length 5, which in this case would be all geohashes that start with "6g3mc". Precision 1 return matches of geohash of length 1, which in this case would be all geohashes that start with "6".

List<String> values = tree.getGeohashesByProximity(-25.686667, -54.444722,5000, precision: 9);

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.