LeafletJS - Multi Polyline and Polygon


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In the previous chapter, we learnt how to add various shapes such as circles, polygons, rectangles, polylines, etc. In this chapter, let us discuss how to add multi-polygons, multirectangles, and polylines.

Multi-Polyline

To draw a multi-polyline overlay on a map using Leaflet JavaScript library, follow the steps given below −

Step 1 − Create a Map object by passing a <div> element (String or object) and map options (optional).

Step 2 − Create a Layer object by passing the URL of the desired tile.

Step 3 − Add the layer object to the map using the addLayer() method of the Map class.

Step 4 − Create a latlangs variable to hold the points to draw the multi-polyline.

// Creating latlng object
var latlang = [
   [[17.385044, 78.486671], [16.506174, 80.648015], [17.686816, 83.218482]],
   [[13.082680, 80.270718], [12.971599, 77.594563],[15.828126, 78.037279]]
];

Step 5 − Create a multi-polyline using the L.multiPolyline() function. Pass the locations as variable to draw a multi-polyline and an option to specify the color and weight of the lines.

// Creating multi polyline options
var multiPolyLineOptions = {color:'red'};

// Creating multi polylines
var multipolyline = L.multiPolyline(latlang , multiPolyLineOptions);

Step 6 − Add multi-polyline to the map using the addTo() method of the Multipolyline class.

// Adding multi polyline to map
multipolyline.addTo(map);

Example

Following is the code to draw a multi-polyline covering the cities Hyderabad, Vijayawada, and Vishakhapatnam; and Kurnool, Bengaluru, and Chennai.

<!DOCTYPE html>
<html>
   <head>
      <title>Leaflet Multi Polylines</title>
      <link rel = "stylesheet" href = "http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.css"/>
      <script src = "http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
   </head>
   
   <body>
      <div id = "map" style = "width: 900px; height: 580px"></div>
      <script>
         // Creating map options
         var mapOptions = {
            center: [16.506174, 80.648015],
            zoom: 7
         }
         // Creating a map object
         var map = new L.map('map', mapOptions);
         
         // Creating a Layer object
         var layer = new L.TileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png');
         
         // Adding layer to the map
         map.addLayer(layer);
         
         // Creating latlng object
         var latlang = [
            [[17.385044, 78.486671], [16.506174, 80.648015], [17.686816, 83.218482]],
            [[13.082680, 80.270718], [12.971599, 77.594563],[15.828126, 78.037279]]
         ];
         
         // Creating poly line options
         var multiPolyLineOptions = {color:'red'};
         
         // Creating multi poly-lines
         var multipolyline = L.multiPolyline(latlang , multiPolyLineOptions);
         
         // Adding multi poly-line to map
         multipolyline.addTo(map);
      </script>
   </body>
   
</html>

It generates the following output −

Multi-Polyline Map

Multi Polygon

To draw a multi-polygon overlay on a map using Leaflet JavaScript library, follow the steps given below −

Step 1 − Create a Map object by passing a <div> element (String or object) and map options (optional).

Step 2 − Create a Layer object by passing the URL of the desired tile.

Step 3 − Add the layer object to the map using the addLayer() method of the Map class.

Step 4 − Create a latlangs variable to hold the points to draw the multi polygon.

// Creating latlng object
var latlang = [
   [[17.385044, 78.486671], [16.506174, 80.648015], [17.686816, 83.218482]],
   [[13.082680, 80.270718], [12.971599, 77.594563],[15.828126, 78.037279]]
];

Step 5 − Create a multi-polygon using the L.multiPolygon() function. Pass the locations as variable to draw the multi-polygon and an option to specify the color and weight of the lines.

// Creating multi polygon options
var multiPolygonOptions = {color:'red'};

// Creating multi polygon
var multipolygon = L.multiPolygon(latlang , multiPolygonOptions);

Step 6 − Add the multi-polygon to the map using the addTo() method of the MultiPolygon class.

// Adding multi polygon to map
multipolygon.addTo(map);

Example

Following is the code to draw a multi-polygon touching the cities Hyderabad, Vijayawada, and Vishakhapatnam; and Kurnool, Bengaluru, and Chennai.

<!DOCTYPE html>
<html>
   <head>
      <title>Leaflet Multi Polygons</title>
      <link rel = "stylesheet" href = "http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.css"/>
      <script src = "http://cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
   </head>
   
   <body>
      <div id = "map" style = "width: 900px; height: 580px"></div>
      <script>
         // Creating map options
         var mapOptions = {
            center: [16.506174, 80.648015],
            zoom: 7
         }
         // Creating a map object
         var map = new L.map('map', mapOptions);
         
         // Creating a Layer object
         var layer = new L.TileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png');
         
         // Adding layer to the map
         map.addLayer(layer);
         
         // Creating latlng object
         var latlang = [
            [[17.385044, 78.486671], [16.506174, 80.648015], [17.686816, 83.218482]],
            [[13.082680, 80.270718], [12.971599, 77.594563],[15.828126, 78.037279]]
         ];
         // Creating multi polygon options
         var multiPolygonOptions = {color:'red', weight:8};
         
         // Creating multi polygons
         var multipolygon = L.multiPolygon(latlang , multiPolygonOptions);
         
         // Adding multi polygon to map
         multipolygon.addTo(map);
      </script>
   </body>
   
</html>

It generates the following output −

Multi Polygon Map

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