polyline 1.0.0 polyline: ^1.0.0 copied to clipboard
Polyline encoding algorithm
polyline.dart #
Polyline encoding is a lossy compression algorithm that allows you to store a series of coordinates as a single string.
Polyline is a dart port of Google's Polyline Algorithm explained here. Inspired by Mapbox's polyline.js. Compatible with Dart 2.
Installation #
Add polyline: any
to your pubspec.yaml.
Then run:
pub get
Usage #
A simple usage example:
Two named constructors are provided Polyline.Decode and Polyline.Encode.
Calling Polyline.Encode will compute the encodedString
and set the passed in coordinates
to decodedCoords
on the instance of Polyline so that each instance of Polyline has access to the correct encoded string
and subsequent decoded coordinates. Likewise, calling Polyline.Decode computes the list of coordinates from the
encoded string and sets the passed in encoded string to the instance of Polyline.
Note that a precision of 5 is standard.
import 'package:polyline/polyline.dart';
void main() {
Polyline polyline;
const coordinates = [
[33.80119, -84.34788],
[35.10566, -80.8762],
[30.4526, -81.71116],
[28.57888, -81.2717]
];
const precision = 5;
const encoded = 'mxhmEfeyaO}w}F_aeTrxk[nabDv}lJsytA';
// Encode a list of coordinates with precision 5 to produce the encoded string
polyline = Polyline.Encode(
decodedCoords: coordinates,
precision: 5
);
print('Encoded String: ${polyline.encodedString}');
print('Coords: ${polyline.decodedCoords}');
// Decode an encoded string to a list of coordinates
polyline = Polyline.Decode(
encodedString: encoded,
precision: precision
);
print('Decoded Coords: ${polyline.decodedCoords}');
print('String: ${polyline.encodedString}');
}
See
Documentation #
Api Documentation
Features and bugs #
Please file feature requests and bugs at the issue tracker.