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, allows for displaying and analyzing GPX tracks and their waypoints so they can be displayed on a Leaflet map as a new layer.

As it parses the GPX data, leaflet-gpx records information about the GPX track, including total time, moving time, total distance, elevation stats and heart-rate, and makes it accessible through an exhaustive set of accessor methods.

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:

Include the Leaflet stylesheet and script, and the leaflet-gpx script, in your HTML page;
Create your Leaflet map, with your choice of base layer(s);
Create the L.GPX layer to display your GPX track.

<html>
  <head>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.9.4/leaflet.css" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.9.4/leaflet.js" defer></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet-gpx/2.1.0/gpx.min.js" defer></script>
    <!-- ... -->
  </head>
  <body>
    <div id="map"></div>
    <!-- ... -->
    <script type="module">
      const 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);

      // URL to your GPX file or the GPX itself as a XML string.
      const url = 'https://mpetazzoni.github.io/leaflet-gpx/demo.gpx';
      const options = {
        async: true,
        polyline_options: { color: 'red' },
      };

      const gpx = new L.GPX(url, options).on('loaded', (e) => {
        map.fitBounds(e.target.getBounds());
      }).addTo(map);
     </script>
  </body>
</html>

Importing from a non-module context

const 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);

await import('gpx.js').then((module) => {
  new L.GPX('https://...').on('loaded', (e) => {
    map.fitBounds(e.target.getBounds());
  }).addTo(map);
});

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(url);
setInterval(function() {
  gpx.reload();
}, 5000);

About marker icons

Configuring markers

By default, leaflet-gpx uses Leaflet's default icon image for all markers. You can override this behavior by providing a Leaflet Icon object, or the path or URL to an image to use as the marker, for any of the markers supported by this plugin as part of the markers parameter:

new L.GPX(url, {
  async: true,
  markers: {
    startIcon: ...,
    endIcon: ...
    wptIcons: { ... },
    wptTypeIcons: { ... },
    pointMatchers: [ ... ],
  }
}).on('loaded', function(e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

startIcon is used for the marker at the beginning of the GPX track;
endIcon is used for the marker at the end of the GPX track;
wptIcons and wptTypeIcons are mappings of waypoint symbols and types to the icon you want to use for each;
pointMatchers is an array of custom point matchers and their respective icon (see below);

You can also override any of those to null to disable the corresponding marker altogether.

Here is how you would override the URL of the provided icons for start and end markers, but none of the other types of markers:

new L.GPX(url, {
  async: true,
  markers: {
    startIcon: 'images/pin-icon-start.png',
    endIcon: 'images/pin-icon-end.png',
  }
}).on('loaded', function(e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

It's usually preferrable and more flexible to provide a Leaflet Icon instance directly, for example from leaflet-awesome-markers. See https://leafletjs.com/examples/custom-icons/ for more information.

new L.GPX(url, {
  async: true,
  markers: {
    wptIcons: {
      'Coffee shop': new L.AwesomeMarkers.icon({
        icon: 'coffee',
        prefix: 'fa',
        markerColor: 'blue',
        iconColor: 'white'
      })
    }
  }
}).on('loaded', function (e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

Marker options

You can fine tune marker options using any of the parameters expected by Leaflet's base L.Icon class using the marker_options parameters:

new L.GPX(url, {
  async: true,
  marker_options: {
    iconSize: [38, 95],
    iconAnchor: [22, 94],
  }
}).on('loaded', function(e) {
  map.fitBounds(e.target.getBounds());
}).addTo(map);

Sensible defaults

Note that you do not need to override all the marker definitions, or marker options, when providing the markers and marker_options parameters to the GPX constructor as this plugin will use sensible defaults for all of those settings.

About waypoints

By default, this plugin will parse all Waypoints from a GPX file. This can be controlled via the value waypoint in gpx_options, e.g. parseElements: ['track', 'route', 'waypoint'].

The icon used in the marker representing each track waypoint is determined based on the waypoint's properties, in this order:

If the waypoint has a sym attribute, the markers.wptIcons[sym] icon is used;
If the waypoint has a type attribute, the markers.wptTypeIcons[type] icon is used;
Point matchers are evaluated in order, if one matches the waypoint's name attribute, its icon is used (see Named markers below);
If none of the above rules match, the default '' (empty string) icon entry in wptIcons is used.

new L.GPX(url, {
  async: true,
  markers: {
    wptIcons: {
      '': new L.Icon.Default,
      'Geocache Found': 'img/gpx/geocache.png',
      'Park': 'img/gpx/tree.png'
    },
  }
}).on('loaded', function (e) {
  map.fitBounds(e.target.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 markers constructor parameter.

Each element in this array must define a regex to match the point's name and an icon definition (a L.Icon or subclass object, or the URL to an icon image).

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(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) {
  map.fitToBounds(e.target.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(url, async: true, {
  // 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);

Note that for your event listeners to be correctly triggered, you need to pass async: true to the L.GPX constructor; otherwise the parsing of the GPX happens synchronously in the constructor before you your event listeners get registered!

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

Selecting which elements define the track

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). The parseElements field of gpx_options controls this behavior. It should be an array that contains 'route' and/or 'track' and/or 'waypoint'.

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.

andilabs/leaflet-gpx