# polyline 1.0.2 polyline: ^1.0.2 copied to clipboard

Polyline encoding algorithm for encoding and decoding a list of coordinates

# 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: ^1.0.2` to your pubspec.yaml. Then run:

``````pub get # flutter 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;

/// List<List<double> coordinates;
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}, 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}');

// Calculate the distance of an encoded polyline, and decode the polyline
polyline =  Polyline.Distance(encodedString: encoded,  unit: 'kilometers');
// By calling  length the encodedString, decodedCoords, and distance variables
// of the Polyline class are available
print('Distance: \${polyline.distance.floor()}km , Encoded String: \${polyline.encodedString} Decoded Coords: \${polyline.decodedCoords}');
``````

## Documentation #

Api Documentation

## Development for v1.0.3 #

Multiple flags for extended capabilities

• [ ] Todo add merge polylines
• [ ] Todo add merge multiple polylines
• [ ] Todo add from geoJson

## Features and bugs #

Please file feature requests and bugs at the issue tracker.

13
likes
75
pub points
88%
popularity

### Publisher

Polyline encoding algorithm for encoding and decoding a list of coordinates