LeafletPlayback

Leaflet Playback provides the ability to replay GPS Tracks in the form of GeoJSON objects. Rather than simply animating a marker along a polyline, the speed of the animation is synchroized to a clock. The playback functionality is similar to a video player--you can start and stop playback, change the playback speed, load GPS tracks, as well as set the playback time with a slider or calendar/time-picker widget.

Examples

Example 0

Basic example of LeafletPlayback plugin, that pre-loads some GPS GeoJSON tracks and lets you play them back.

Example 1

Use vis.js timeline as slider control

Example 2

Custom interface example - Includes the usage of Maki Markers and Twitter Bootstrap.

Example 3

Shows the ability to have markers orient themselves to the bearing of the track.

Virtual Fence Demo

I began my work on LeafletPlayback in my web mapping class at Oregon State University. My final project involved animating GPS tracks that triggered geo-fences. Note: this may stop working on August 2015 when Geoloqui will discontinue their web services.

GPS Data Format

Leaflet Playback consumes GPS tracks in the form of GeoJSON. Limited GPX import is provided with the L.Playback.Util.ParseGPX() convertion function. The schema of the GeoJSON data is as follows:

{
  "type": "Feature",
  "geometry": {
    "type": "MultiPoint",
    "coordinates": [/*array of [lng,lat] coordinates*/]
  },
  "properties": {
    "time": [/*array of UNIX timestamps*/]
  }
}

Other attributes may be added to the GeoJSON object, but this is the required minimum schema for the plug-in to work.

There are three leaflet controls defined in src/Controls.js:

1. L.Playback.DateControl - Current tick date/time;
2. L.Playback.PlayControl - Play/stop button to control time flow of LeafletPlayback;
3. L.Playback.SliderControl - Simple time slider;

Usage

API

new L.Playback(map, geoJSON, onPlaybackTimeChange, options)

parameters

var playback = new L.Playback(map, geoJSON, onPlaybackTimeChange, options);

• map - LeafLet map object. Required.
• geoJSON - GeoJSON object or an array of GeoJSON objects. Pass null if you don't have any data yet. Required.
• onPlaybackTimeChange - A function with signature (timestamp) that will send the timestamp value on each tick. Required.
• options - An options object. Optional.

options

• tickLen - Set tick length in miliseconds. Increasing this value, may improve performance, at the cost of animation smoothness. Default: 250.
• speed - Set float multiplier for default animation speed. Default: 1.
• maxInterpolationTime - Set max interpolation time in seconds. Default: 5*60*1000 (5 minutes).
• tracksLayer - Set true if you want to show layer control on the map. Default: true.
• playControl - Set true if play button is needed. Default: false.
• dateControl - Set true if date label is needed. Default: false.
• sliderControl - Set true if slider control is needed. Default: false.
• layer - Object or function with signature (featureData) that returns geoJSON layer options object. Useful for setting path color. Default: {}.
• marker - Object or function with signature (featureData) that returns leaflet marker options, to extend L.Playback.MoveableMarker. Useful for custom icons. Default: {}.
  • Added custom option, transformOrigin to allow setting of rotation point if orientIcon options is set to true
• orientIcons - Set true if you want icons to orient themselves on each tick based on the bearing towards their next location. Default: false.
• mouseOverCallback - A function with signature (event) that will be sent events on 'mouseover' on each marker Optional.
• clickCallback - A function with signature (event) that will be sent events on 'click' on each marker Optional.
• popups - Set true if popups on markers are required. Default: false.
• labels - Set true if labels on markers are required. Uses leaflet-markers (https://github.com/Leaflet/Leaflet.label) Default: false.
• staleTime - Set time before a track is considered stale and faded out. Default: 60*60*1000 (1 hour).
• fadeMarkersWhenStale - Set true markers should hide when not yet present in time and fade out after staleTime has passed Default: false.

playback#setData(geoJSON)

Reset current data and add new.

• geoJSON - GeoJSON object or an array of GeoJSON objects. Required.

playback#addData(geoJSON)

Add new data.

• geoJSON - GeoJSON object or an array of GeoJSON objects. Required.

playback#clearData()

Clear all data and tracks layer.

L.Playback.Util.ParseGPX(gpxString)

Convert gpxString content into geoJSON that can be used as input data for Playback().

• gpxString - a string containg the content of a GPX file. Required.