4

I need to get the current user location automatically every "X" seconds (5 or 10 sec.) and put it on a simple Leaflet map.

I've seen the Leaflet on Mobile sample here http://leafletjs.com/examples/mobile.html ...

<!DOCTYPE html>
<html>
<head>
    <title>Leaflet mobile example</title>

    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">

    <link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.css" />

    <script src="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js"></script>

    <style>
        body {
        padding: 0;
        margin: 0;
        }
        html, body, #map {
        height: 100%;
    }
    </style>
</head>
<body>
<div id="map"></div>

<script>
    var map = L.map('map');

    L.tileLayer('https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token=pk.eyJ1IjoibWFwYm94IiwiYSI6ImNpandmbXliNDBjZWd2M2x6bDk3c2ZtOTkifQ._QA7i5Mpkd_m30IGElHziw', {
        maxZoom: 18,
        attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
            '<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
            'Imagery © <a href="http://mapbox.com">Mapbox</a>',
        id: 'mapbox.streets'
    }).addTo(map);

    function onLocationFound(e) {
        var radius = e.accuracy / 2;

        L.marker(e.latlng).addTo(map)
            .bindPopup("You are within " + radius + " meters from this point").openPopup();

        L.circle(e.latlng, radius).addTo(map);
    }

    function onLocationError(e) {
        alert(e.message);
    }

    map.on('locationfound', onLocationFound);
    map.on('locationerror', onLocationError);

    map.locate({setView: true, maxZoom: 16});
    </script>
</body>
</html>

... and could be useful as starting point for me but I don't know how to refresh the current user location without refresh / reload all the map, that obviously it's not the solution.

Does someone have any sample code that could help me?

6

With a couple of modifications, you can use setInterval() as a timer, and remove the existing user position on each pass.

From the same example, here is the complete code, with additional comments inline:

<!DOCTYPE html>
<html>
<head>
  <title>Leaflet mobile example</title>

  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">

  <link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.css" />

  <script src="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js"></script>

  <style>
    body {
      padding: 0;
      margin: 0;
    }
    html, body, #map {
      height: 100%;
    }
  </style>
</head>
<body>
  <div id="map"></div>

  <script>
    var map = L.map('map');

    L.tileLayer('https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token=pk.eyJ1IjoibWFwYm94IiwiYSI6ImNpandmbXliNDBjZWd2M2x6bDk3c2ZtOTkifQ._QA7i5Mpkd_m30IGElHziw', {
      maxZoom: 18,
      attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
        '<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, ' +
        'Imagery © <a href="http://mapbox.com">Mapbox</a>',
      id: 'mapbox.streets'
    }).addTo(map);

    // placeholders for the L.marker and L.circle representing user's current position and accuracy    
    var current_position, current_accuracy;

    function onLocationFound(e) {
      // if position defined, then remove the existing position marker and accuracy circle from the map
      if (current_position) {
          map.removeLayer(current_position);
          map.removeLayer(current_accuracy);
      }

      var radius = e.accuracy / 2;

      current_position = L.marker(e.latlng).addTo(map)
        .bindPopup("You are within " + radius + " meters from this point").openPopup();

      current_accuracy = L.circle(e.latlng, radius).addTo(map);
    }

    function onLocationError(e) {
      alert(e.message);
    }

    map.on('locationfound', onLocationFound);
    map.on('locationerror', onLocationError);

    // wrap map.locate in a function    
    function locate() {
      map.locate({setView: true, maxZoom: 16});
    }

    // call locate every 3 seconds... forever
    setInterval(locate, 3000);

  </script>
</body>
</html> 
1

I was using this library to work with react, and I was looking on a way to set the map to the user's current location. The following should work.

The .locate calls the api method to search for the user's current location. Set view updates the map, maxZoom attempts to zoom the map 16 ticks.

var map = L.map('map').locate({setView: true, maxZoom: 16});

My react component has the following function:

componentDidMount: function() {
var map = L.map('map').locate({setView: true, maxZoom: 16});
L.esri.basemapLayer('Gray').addTo(map);

// create the geocoding control and add it to the map
var searchControl = L.esri.Geocoding.geosearch().addTo(map);

// create an empty layer group to store the results and add it to the map
var results = L.layerGroup().addTo(map);

// listen for the results event and add every result to the map
searchControl.on("results", function(data) {
    results.clearLayers();
    for (var i = data.results.length - 1; i >= 0; i--) {
        results.addLayer(L.marker(data.results[i].latlng));
    }
});

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