GPX plugin for Leaflet

Leaflet is a Javascript library for displaying interactive maps. This plugin, based on the work of Pavel Shramov and his leaflet-plugins, it allows for the analysis and parsing of a GPX track in order to display it as a Leaflet map layer. As it parses the GPX data, it will record information about the recorded track, including total time, moving time, total distance, elevation stats and heart-rate.

GPX parsing will automatically handle pauses in the track with a default tolerance interval of 15 seconds between points. You can configure this interval by setting max_point_interval, in milliseconds, in the options passed to the GPX constructor.

I've put together a complete example as a demo.

License

leaflet-gpx is under the BSD 2-clause license. Please refer to the attached LICENSE file and/or to the copyright header in gpx.js for more information.

Usage

Usage is very simple. First, include the Leaflet.js and Leaflet-GPX scripts in your HTML page:

<html>
  <head>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.7.1/leaflet.css" />
    <!-- ... -->
  </head>
  <body>
    <!-- ... -->
    <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.7.1/leaflet.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet-gpx/1.7.0/gpx.min.js"></script>
  </body>
</html>

Now, let's consider we have a Leaflet map:

var map = L.map('map');
L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
  attribution: 'Map data &copy; <a href="http://www.osm.org">OpenStreetMap</a>'
}).addTo(map);

Displaying a GPX track on it is as easy as:

var gpx = '...'; // URL to your GPX file or the GPX itself
new L.GPX(gpx, {async: true}).on('loaded', function(e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

Some GPX tracks contain the actual route/track twice, both the <trk> and <rte> elements are used. You can tell leaflet-gpx which tag to use or to use both (which is the default setting for backwards compatibility) with the gpx_options object in the second argument of the constructor. The member parseElements controls this behavior, it should be an array that contains 'route' and/or 'track'.

Available functions

If you want to display additional information about the GPX track, you can do so in the 'loaded' event handler, calling one of the following methods on the GPX object e.target:

get_name(): returns the name of the GPX track
get_distance(): returns the total track distance, in meters
get_start_time(): returns a Javascript Date object representing the starting time
get_end_time(): returns a Javascript Date object representing when the last point was recorded
get_moving_time(): returns the moving time, in milliseconds
get_total_time(): returns the total track time, in milliseconds
get_moving_pace(): returns the average moving pace in milliseconds per km
get_moving_speed(): returns the average moving speed in km per hour
get_total_speed(): returns the average total speed in km per hour
get_elevation_min(): returns the lowest elevation, in meters
get_elevation_max(): returns the highest elevation, in meters
get_elevation_gain(): returns the cumulative elevation gain, in meters
get_elevation_loss(): returns the cumulative elevation loss, in meters
get_speed_max(): returns the maximum speed in km per hour
get_average_hr(): returns the average heart rate (if available)
get_average_cadence(): returns the average cadence (if available)
get_average_temp(): returns the average of the temperature (if available)

If you're not a fan of the metric system, you also have the following methods at your disposal:

get_distance_imp(): returns the total track distance in miles
get_moving_pace_imp(): returns the average moving pace in milliseconds per hour
get_moving_speed_imp(): returns the average moving speed in miles per hour
get_total_speed_imp(): returns the average total speed in miles per hour
get_elevation_min_imp(): returns the lowest elevation, in feet
get_elevation_max_imp(): returns the highest elevation, in feet
get_elevation_gain_imp(): returns the cumulative elevation gain, in feet
get_elevation_loss_imp(): returns the cumulative elevation loss, in feet
get_speed_max_imp(): returns the maximum speed in miles per hour

The reason why these methods return milliseconds is that you have at your disposal nice helper methods to format a duration in milliseconds into a cool string:

get_duration_string(duration, hidems) format to a string like 3:07'48" or 59'32.431, where duration is in milliseconds and hidems is an optional boolean you can use to request never to display millisecond precision.
get_duration_string_iso(duration, hidems) formats to an ISO like representation like 3:07:48 or 59:32.431, where duration is in milliseconds and hidems is an optional boolean you can use to request never to display millisecond precision.

You can also get full elevation, heartrate, cadence and temperature data with:

get_elevation_data() and get_elevation_data_imp()
get_speed_data and get_speed_data_imp()
get_heartrate_data() and get_heartrate_data_imp()
get_cadence_data() and get_cadence_data_imp()
get_temp_data() and get_temp_data_imp()

These methods all return an array of points [distance, value, tooltip] where the distance is either in kilometers or in miles and the elevation in meters or feet, depending on whether you use the _imp variant or not. Heart rate, obviously, doesn't change.

Reloading

You can make leaflet-gpx reload the source GPX file by calling the reload() method. For example, to trigger a reload every 5 seconds, you can do:

var gpx = new L.GPX(gpxFile);
setInterval(function() {
  gpx.reload();
}, 5000);

About marker icons

By default gpx.js will use pin-icon-start.png, pin-icon-end.png and pin-shadow.png as the marker icons URLs for, respectively, the start marker, the end marker and their drop shadow. Since it might not be convenient that these images have to reside under the same directory as your HTML page, it is possible to override the marker icon URLs and sizes by passing a marker_options object to the GPX options object.

The field names are the same as for custom Leaflet icons, as explained in the Markers with custom icons page in Leaflet's documentation. The only difference is that instead of iconUrl you should specify startIconUrl and endIconUrl for the start and end markers, respectively.

Note that you do not need to override all the marker icon options as gpx.js will use sensible defaults with sizes matching the provided icon images. Here is how you would override the URL of the provided icons if you decided to place them in an images/ directory:

var url = '...'; // URL to your GPX file
new L.GPX(url, {
  async: true,
  marker_options: {
    startIconUrl: 'images/pin-icon-start.png',
    endIconUrl: 'images/pin-icon-end.png',
    shadowUrl: 'images/pin-shadow.png'
  }
}).on('loaded', function(e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

About waypoints

By default gpx.js will parse Waypoints from a GPX file. This may also be steered via the value waypoint in gpx_options, e.g. parseElements: ['track', 'route', 'waypoint'].

Waypoint icons: by default the pin-icon-wpt.png icon is shown for each waypoint. This can be overridden by setting marker_options.wptIconUrls in the L.GPX constructor options, as a mapping from the waypoint "SYM" name to a user-supplied icon file or URL. The empty string '' is used by the waypoint tag does not define a "SYM" name. See the example below:

new L.GPX(app.params.gpx_url, {
  async: true,
  marker_options: {
    wptIconUrls: {
      '': 'img/gpx/default-waypoint.png',
      'Geocache Found': 'img/gpx/geocache.png',
      'Park': 'img/gpx/tree.png'
    },
    ...
    shadowUrl: 'http://github.com/mpetazzoni/leaflet-gpx/raw/master/pin-shadow.png'
  }
}).on('loaded', function (e) {
  var gpx = e.target;
  map.fitBounds(gpx.getBounds());
}).addTo(map);

Custom markers

You can also use your own icons/markers if you want to use custom markers, for example from leaflet-awesome-markers. To specify you own markers, set startIcon, endIcon, and a map of wptIcons by waypoint symbol (see above). Those should be marker icon objects usable by Leaflet as the icon property of a L.Marker object.

new L.GPX(app.params.gpx_url, {
  async: true,
  marker_options: {
    wptIcons: {
      'Coffee shop': new L.AwesomeMarkers.icon({
        icon: 'coffee',
        prefix: 'fa',
        markerColor: 'blue',
        iconColor: 'white'
      })
    }
  }
}).on('loaded', function (e) {
  var gpx = e.target;
  map.fitBounds(gpx.getBounds());
}).addTo(map);

Named points

GPX points can be named, for example to denote certain POIs (points of interest). You can setup rules to match point names to create labeled markers for those points by providing a pointMatchers array in the marker_options. Each element in this array must define a regex to match the point's name and an icon object (any L.Marker or for example an L.AwesomeMarkers.icon as shown above in Custom markers).

Each named point in the GPX track is evaluated against those rules and a marker is created with the point's name as label from the first matching rule. This also applies to named waypoints, but keep in mind that waypoint icons rules take precedence over point matchers.

new L.GPX(app.params.gpx_url, {
  async: true,
  marker_options: {
    pointMatchers: [
      {
        regex: /Coffee/,
        icon: new L.AwesomeMarkers.icon({
          icon: 'coffee',
          markerColor: 'blue',
          iconColor: 'white'
        }),
      },
      {
        regex: /Home/,
        icon: new L.AwesomeMarkers.icon({
          icon: 'home',
          markerColor: 'green',
          iconColor: 'white'
        }),
      }
    ]
  }
}).on('loaded', function(e) {
  var gpx = e.target;
  map.fitToBounds(gpx.getBounds());
}).addTo(map);

Events

Events are fired on the L.GPX object as the GPX data is being parsed and the map layers generated. You can listen for those events by attaching the corresponding event listener on the L.GPX object:

new L.GPX(app.params.gpx_url, {
  // options
}).on('addpoint', function(e) {
  console.log('Added ' + e.point_type + ' point: ' + e.point);
}).on('loaded', function(e) {
  var gpx = e.target;
  map.fitToBounds(gpx.getBounds());
}).on('error', function(e) {
  console.log('Error loading file: ' + e.err);
}).addTo(map);

addpoint events are fired for every marker added to the map, in particular for the start and end points, all the waypoints, and all the named points that matched pointMatchers rules. Each addpoint event contains the following properties:

point: the marker object itself, from which you can get or modify the latitude and longitude of the point and any other attribute of the marker.
point_type: one of start, end, waypoint or label, allowing you to identify what type of point the marker is for.
element: the track point element the marker was created for.

One use case for those events is for example to attach additional content or behavior to the markers that were generated (popups, etc).

error events are fired when no layers of the type(s) specified in options.gpx_options.parseElements can be parsed out of the given file. For instance, error would be fired if a file with no waypoints was attempted to be loaded with parseElements set to ['waypoint']. Each error event contains the following property:

err: a message with details about the error that occurred.

Line styling

leaflet-gpx understands the GPX Style extension, and will extract styling information defined on routes and track segments to use for drawing the corresponding polyline.

<trkseg>
  <extensions>
    <line xmlns="http://www.topografix.com/GPX/gpx_style/0/2">
      <color>FF0000</color>
      <opacity>0.5</opacity>
      <weight>1</weight>
      <linecap>square</linecap>
      <linejoin>square</linejoin>
      <dasharray>0,10</dasharray>
      <dashoffset>3</dashoffset>
    </line>
  </extensions>
  <trkpt lat="..." lon="..."></trkpt>
</trkseg>

You can override the style of the lines by passing a polyline_options array into the options argument of the L.GPX constructor, each element of the array defines the style for the corresponding route and/or track in the file (in the same order).

new L.GPX(url, {
  polyline_options: [{
    color: 'green',
    opacity: 0.75,
    weight: 3,
    lineCap: 'round'
  },{
    color: 'blue',
    opacity: 0.75,
    weight: 1
  }]
}).on('loaded', function(e) {
  var gpx = e.target;
  map.fitToBounds(gpx.getBounds());
}).addTo(map);

If you have many routes or tracks in your GPX file and you want them to share the same styling, you can pass polyline_options as a single object rather than an array (this is also how leaflet-gpx worked before the introduction of the array):

new L.GPX(url, {
  polyline_options: {
    color: 'green',
    opacity: 0.75,
    weight: 3,
    lineCap: 'round'
  }
}).on('loaded', function(e) {
  var gpx = e.target;
  map.fitToBounds(gpx.getBounds());
}).addTo(map);

For more information on the available polyline styling options, refer to the Leaflet documentation on Polyline. By default, if no styling is available, the line will be drawn in blue.

GPX parsing options

Multiple track segments within each track

GPX file may contain multiple tracks represented by <trk> elements, each track possibly composed of multiple segments with <trkseg> elements. Although this plugin will always represent each GPX route and each GPX track as distinct entities with their own start and end markers, track segments will by default be joined into a single line.

You can disable this behavior by setting the joinTrackSegments flag to false in the gpx_options:

new L.GPX(url, {
  gpx_options: {
    joinTrackSegments: false
  }
}).on('loaded', function(e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

Caveats

Distance calculation is relatively accurate, but elevation change calculation is not topographically adjusted, so the total elevation gain/loss/change might appear inaccurate in some situations.
Currently doesn't seem to work in IE8/9. See #9 and #11 for discussion.

mpetazzoni/leaflet-gpx

mpetazzoni

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