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javascriptleafletgeojson

Draw lines between markers in leaflet

I'm trying to insert lines between markers (which are generated from JSON data) in leaflet. I saw an example, but it doesn't work with JSON data. I can see the markers, but no lines appear.

var style = {
  color: 'red',
  fillColor: "#ff7800",
  opacity: 1.0,
  fillOpacity: 0.8,
  weight: 2
};

$.getJSON('./server?id_dispositivo=' + id_device + '', function(data) {
  window.geojson = L.geoJson(data, {
    onEachFeature: function (feature, layer) {
      var Icon = L.icon({
        iconUrl: './images/mymarker.png',
        iconSize: [18, 28], // size of the icon
        style: style,
      });
      layer.setIcon(Icon);
      layer.bindPopup(feature.properties.date + '<br />' + feature.properties.id);
    }
  });
});
map.addLayer(geojson);

enter image description here

My JSON data:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [
          -70.219841,
          8.6310997
        ]
      },
      "properties": {
        "id": 336,
        "id_user": 1,
        "id_device": 1,
        "timestamp": 1446571154,
        "date": "12:49PM 03-11-2015",
        "Latitude": 8.6310997,
        "Longitude": -70.219841,
        "speedKPH": 0,
        "heading": "",
        "Name": "N\/D",
        "City": "N\/D",
        "estatus": "Stop"
      }
    }
  ]
}
Solution

  • There are many ways you could do this by iterating over either the original GeoJSON or the resulting L.GeoJson layer to produce a polyline geometry. Here is one simple function that will turn a L.geoJson layer of points into an array of coordinates that can be passed to L.polyline:

    function connectTheDots(data){
    var c = [];
    for(i in data._layers) {
        var x = data._layers[i]._latlng.lat;
        var y = data._layers[i]._latlng.lng;
        c.push([x, y]);
    }
    return c;
}

    and here is a fiddle showing it at work on some synthetic GeoJSON data:

    http://jsfiddle.net/nathansnider/36twhxux/

    Assuming that your GeoJSON data contains only point geometry, you should be able to use it after you define window.geojson within your $.getJSON success function like so:

    pathCoords = connectTheDots(window.geojson);
var pathLine = L.polyline(pathCoords).addTo(map)

    If your GeoJSON data are more complex, you might need to add some conditionals to check for geometry type, etc., but this should at least give you a general idea of how to proceed.