trajectory.js

A simple google-esque polyline inspired implementation in Javascript, extended to trajectory data structure (an additional time dimension added to the GPS coordinates). Compatible with nodejs (npm install trajectory.js and the browser (copy src/trajectory.js)).

Encodes from/decodes into [lat, lng, unix time in seconds] tuples.

This library is heavily based on https://github.com/mapbox/polyline (In fact it is built on top of fork of it)

Installation

npm install trajectory.js

Example

1var trajectory = require('trajectory.js');
2
3// returns an array of (lat, lon, unix time in seconds) tuples
4trajectory.decode('_p~iF~ps|U_ynpijgz~G_ulLnnqC_c`|@_mqNvxq`@__t`B');
5
6// returns an array of (lat, lon, unix time in seconds) tuples from trajectory6 by passing a precision parameter
7trajectory.decode('_izlhA~rlgdF_c}mhpro}xA_{geC~ywl@_gjaR_kwzCn`{nI__qo]', 6);
8
9// returns a string-encoded trajectory
10trajectory.encode([[38.5, -120.2, 1582482601], [40.7, -120.95, 1582482611], [43.252, -126.453, 1582482627]]);
11

API Documentation

trajectory.decode(string[, precision])

Takes a string representation of 1+ coordinate pairs and returns an array of (lat, lon, unix time in seconds) arrays. If not specified, precision defaults to 5.

trajectory.encode(array[, precision])

Takes an array of (lat, lon, unix time in seconds) arrays and returns an encoded string. If not specified, precision defaults to 5.

Command line

Install globally or run ./node_modules/.bin/trajectory.

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

Example :

1$ echo '_p~iF~ps|U_ynpijgz~G_ulLnnqC_c`|@_mqNvxq`@__t`B' | ./bin/trajectory.bin.js
2
3$ echo '[[38.5,-120.2,1582482601],[40.7,-120.95,1582482611],[43.252,-126.453,1582482627]]' | ./bin/trajectory.bin.js --encode

Contributing

Issues and pull requests are welcome.

• For proposing new features/improvements or reporting bugs, create an issue.
• Check open issues for viewing existing ideas, verify if it is already proposed/being worked upon.
• When implementing new features make sure to add relavant tests and documentation before sending pull requests.