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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <html>
<head>
	<title>Multiple routes</title>
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<link rel="stylesheet" href="https://unpkg.com/leaflet@1.3.1/dist/leaflet.css" integrity="sha512-Rksm5RenBEKSKFjgI3a41vrjkw4EVPlJ3+OiI65vTjIdo9brlAacEuKOiQ5OFh7cOI1bkDwLqdLw3Zg0cRJAAQ==" crossorigin=""/>
	<script src="https://unpkg.com/leaflet@1.3.1/dist/leaflet.js"
   integrity="sha512-/Nsx9X4HebavoBvEBuyp3I7od5tA0UzAxs+j83KgC8PU0kgB4XiK4Lfe4y4cgBtaRJQEIFCW+oC506aPT2L1zw==" crossorigin=""></script>
   	<style>#mapid {width: 800px; height: 600px; border: 1px solid #ccc;}</style>
	<script src="https://unpkg.com/leaflet.markercluster@1.3.0/dist/leaflet.markercluster.js"></script>
</head>
<body>
<div id="mapid"></div>
<script type="text/javascript">
	var mymap = L.map('mapid');
	// Fallback view: North of the equator, along Greenwich Meridian.
	// If "bounds-finding" fails, one marker should show up on both East and West edges of the map!
	mymap.setView([33,0],3); 
	// My dataset of three routes: (1) a random line somewhere north of India (roughly), 
	// (2) the same but mirrored along Greenwich meridian, so it's across the Eastern USA and Cuba (roughly).
	// and (3) same as first but scaled 10x smaller towards (0,0).
	var routeData = [
		[[33, 77], [33, 88], [22, 77], [44, 66], [44, 99], [38.5, 93.5], [38.5, 77]],
		[[33, -77], [33, -88], [22, -77], [44, -66], [44, -99], [38.5, -93.5], [38.5, -77]],
		[[3, 7], [3, 8], [2, 7], [4, 6], [4, 9], [3.5, 9.5], [3.5, 7]]
		];
	// add map layer with attributions
	L.tileLayer('https://cartodb-basemaps-{s}.global.ssl.fastly.net/light_all/{z}/{x}/{y}.png', {
	maxZoom: 5, minZoom: 2, attribution: 'mapdata &copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a>, styling &copy; <a href="http://cartodb.com/attributions">CartoDB</a>', subdomains: 'abcd'}).addTo(mymap);

	// automatic "bounds-finding" variable:
	var bounds = new L.LatLngBounds();
	//Here I'm using Leaflet.MarkerCluster --- I haven't figured out yet whether the problem lies here or not
	var markers = L.markerClusterGroup();
	
	// I'll loop through the routes (1,2,3; using variable j=0,1,2) then through the points on them (seven each, using variable i=0,1,..,6)
	// So there's an array of routes to be initialized, 
	// and each of them will get a polyline, 
	// and all those LatLong-pairs will end up together in an array of arrays called "latlngs":
	var routes = [];	
  var polyline = [];		
	var latlngs = [[]];

	for (var j = 0; j < routeData.length; j++) {
    /*
    latlngs[j] = []; // SOLUTION!
    */
    
	// For each route: Declare it's a marker cluster/group, then 
		routes[j] = markers;
		for (var i = 0; i < routeData[j].length; i++) {
			var a = routeData[j][i];
			latlngs[j]=latlngs[j].concat([[a[0],a[1]]]);
			var loc = new L.LatLng(a[0], a[1]);
			bounds.extend(loc);
			var marker = L.marker(loc);
			marker.bindPopup('Route '.concat(String(j+1),', marker ', String(i+1)));
			routes[j].addLayer(marker);
			}
		polyline[j] = L.polyline(latlngs[j]).addTo(routes[j]);
		mymap.addLayer(routes[j]);
		}
	mymap.fitBounds(bounds);
</script>
</body>
</html>
            
          
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