https://github.com/mapbox/polyline

polyline encoding and decoding in javascript
https://github.com/mapbox/polyline

Last synced: about 2 months ago
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polyline encoding and decoding in javascript

• Host: GitHub
• URL: https://github.com/mapbox/polyline
• Owner: mapbox
• License: bsd-3-clause
• Created: 2012-07-19T16:41:21.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2024-04-10T11:01:09.000Z (5 months ago)
• Last Synced: 2024-07-16T06:41:48.338Z (2 months ago)
• Language: JavaScript
• Size: 484 KB
• Stars: 630
• Watchers: 129
• Forks: 101
• Open Issues: 14
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
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polyline

---

A simple [google-esque polyline](https://developers.google.com/maps/documentation/utilities/polylinealgorithm)

implementation in Javascript. Compatible with nodejs (`npm install @mapbox/polyline` and the browser (copy `src/polyline.js`)).

Encodes from / decodes into `[lat, lng]` coordinate pairs. Use `fromGeoJSON()` to encode from GeoJSON objects, or `toGeoJSON` to

decode to a GeoJSON LineString.

## Installation

    npm install @mapbox/polyline

    

Note that the old package `polyline` has been deprecated in favor of `@mapbox/polyline` (the old package remain but won't receive updates).

## Example

```js

var polyline = require('@mapbox/polyline');

// returns an array of lat, lon pairs

polyline.decode('_p~iF~ps|U_ulLnnqC_mqNvxq`@');

// returns an array of lat, lon pairs from polyline6 by passing a precision parameter

polyline.decode('cxl_cBqwvnS|Dy@ogFyxmAf`IsnA|CjFzCsHluD_k@hi@ljL', 6);

// returns a GeoJSON LineString Geometry

polyline.toGeoJSON('_p~iF~ps|U_ulLnnqC_mqNvxq`@');

// returns a string-encoded polyline (from coordinate ordered lat,lng)

polyline.encode([[38.5, -120.2], [40.7, -120.95], [43.252, -126.453]]);

// returns a string-encoded polyline from a GeoJSON LineString

polyline.fromGeoJSON({ "type": "Feature",

  "geometry": {

    "type": "LineString",

    "coordinates": [[-120.2, 38.5], [-120.95, 40.7], [-126.453, 43.252]]

  },

  "properties": {}

});

```

[API Documentation](https://github.com/mapbox/polyline/blob/master/API.md)

## Command line

Install globally or run `./node_modules/.bin/polyline`.

Send input via stdin and use `--decode`, `--encode`, `--toGeoJSON`, or `--fromGeoJSON` flags. If omitted will default to `--decode`.

Example :

```

cat file.json | ./bin/polyline.bin.js --fromGeoJSON > result.txt

```