georange
Georange is a package that helps with encoding geohashes, decoding geohashes,calculating distance between 2 points and generating latitudinal and longitudinal ranges as geohashes to help with the querying of databases (Tested on Firestore Only).
Heavily influenced by GeoFlutterFire
Getting Started
You should ensure that you add Georange as a dependency in your flutter project.
dependencies:
georange: <latest-version>
You should then run flutter packages get
Example
There is a detailed example project in the example folder.
Initialize
Import georange to your dart file and initialize
import 'package:georange/georange.dart';
GeoRange georange = GeoRange();
Encode LatLng
This method encodes the latitude and longitude
var encoded = georange.encode(-1.2862368,36.8195783);
print(encoded);
prints kzf0tvg5n
Decode Geohash
Decode a [geohash] into a pair of latitude and longitude.
Point decoded = georange.decode("kzf0tvg5n");
print(decoded);
prints -1.2862372398376465 36.819584369659424
Generate Range
Range range = georange.geohashRange(-1.2921, 36.8219, distance: 10);
print(range.lower);
print(range.upper);
prints kzf05k6hh kzf30mptu
Calculate Distance between 2 Points
Point point1 = Point(latitude: -4.0435, longitude: 39.6682); //Mombasa
Point point2 = Point(latitude: -1.2921, longitude: 36.8219); // Nairobi
var distance = georange.distance(point1, point2);
print(distance);
prints 439.716 Distance in Kilometres
Usage with Firestore
- Add a document to firestore with a
geohashfield or a different name
final FirebaseFirestore _db;
...
String myhash = georange.encode(-1.2862368,36.8195783);
await _db.collection("locations").add({
"geohash":myhash,
})
...
- Query Firestore (Runs like a normal firestore query)
final FirebaseFirestore _db;
GeoRange georange = GeoRange();
Range range = georange.geohashRange(currentLocation.latitude, currentLocation.longitude, distance:10);
QuerySnapshot snapshot = await _db
.collection("locations")
.where("geohash", isGreaterThanOrEqualTo: range.lower)
.where("geohash", isLessThanOrEqualTo: range.upper)
.limit(10)
.get();
8 Oct 31, 2022
3 Sep 7, 2021
2 Oct 17, 2022
20 Jun 7, 2022
2 Apr 17, 2022
47 Oct 27, 2022
2 Sep 1, 2022
2 Jan 28, 2022
1.7k Dec 28, 2022
30 Dec 29, 2022