[javascript] Google Maps JS API v3 - Simple Multiple Marker Example

Fairly new to the Google Maps Api. I've got an array of data that I want to cycle through and plot on a map. Seems fairly simple, but all the multi-marker tutorials I have found are quite complex.

Let's use the data array from google's site for an example:

var locations = [
  ['Bondi Beach', -33.890542, 151.274856, 4],
  ['Coogee Beach', -33.923036, 151.259052, 5],
  ['Cronulla Beach', -34.028249, 151.157507, 3],
  ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
  ['Maroubra Beach', -33.950198, 151.259302, 1]
];

I simply want to plot all of these points and have an infoWindow pop up when clicked to display the name.

This question is related to javascript google-maps google-maps-api-3

The answer is


Asynchronous version :

<script type="text/javascript">
  function initialize() {
    var locations = [
      ['Bondi Beach', -33.890542, 151.274856, 4],
      ['Coogee Beach', -33.923036, 151.259052, 5],
      ['Cronulla Beach', -34.028249, 151.157507, 3],
      ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
      ['Maroubra Beach', -33.950198, 151.259302, 1]
    ];

    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 10,
      center: new google.maps.LatLng(-33.92, 151.25),
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });

    var infowindow = new google.maps.InfoWindow();

    var marker, i;

    for (i = 0; i < locations.length; i++) {  
      marker = new google.maps.Marker({
        position: new google.maps.LatLng(locations[i][1], locations[i][2]),
        map: map
      });

      google.maps.event.addListener(marker, 'click', (function(marker, i) {
        return function() {
          infowindow.setContent(locations[i][0]);
          infowindow.open(map, marker);
        }
      })(marker, i));
    }
}

function loadScript() {
  var script = document.createElement('script');
  script.type = 'text/javascript';
  script.src = 'https://maps.googleapis.com/maps/api/js?v=3.exp&' +
      'callback=initialize';
  document.body.appendChild(script);
}

window.onload = loadScript;
  </script>

Source Link

Demo Link

Complete HTML code

  • Show InfoWindow on Click or Hover.
  • Only one InfoWindow will be shown

enter image description here

    <!DOCTYPE html>
    <html>

    <head>
        <style>
            /*  <span class="metadata-marker" style="display: none;" data-region_tag="css"></span>       Set the size of the div element that contains the map */
            #map {
                height: 400px;
                /* The height is 400 pixels */
                width: 100%;
                /* The width is the width of the web page */
            }
        </style>
        <script>
            var map;
            var InforObj = [];
            var centerCords = {
                lat: -25.344,
                lng: 131.036
            };
            var markersOnMap = [{
                    placeName: "Australia (Uluru)",
                    LatLng: [{
                        lat: -25.344,
                        lng: 131.036
                    }]
                },
                {
                    placeName: "Australia (Melbourne)",
                    LatLng: [{
                        lat: -37.852086,
                        lng: 504.985963
                    }]
                },
                {
                    placeName: "Australia (Canberra)",
                    LatLng: [{
                        lat: -35.299085,
                        lng: 509.109615
                    }]
                },
                {
                    placeName: "Australia (Gold Coast)",
                    LatLng: [{
                        lat: -28.013044,
                        lng: 513.425586
                    }]
                },
                {
                    placeName: "Australia (Perth)",
                    LatLng: [{
                        lat: -31.951994,
                        lng: 475.858081
                    }]
                }
            ];

            window.onload = function () {
                initMap();
            };

            function addMarkerInfo() {
                for (var i = 0; i < markersOnMap.length; i++) {
                    var contentString = '<div id="content"><h1>' + markersOnMap[i].placeName +
                        '</h1><p>Lorem ipsum dolor sit amet, vix mutat posse suscipit id, vel ea tantas omittam detraxit.</p></div>';

                    const marker = new google.maps.Marker({
                        position: markersOnMap[i].LatLng[0],
                        map: map
                    });

                    const infowindow = new google.maps.InfoWindow({
                        content: contentString,
                        maxWidth: 200
                    });

                    marker.addListener('click', function () {
                        closeOtherInfo();
                        infowindow.open(marker.get('map'), marker);
                        InforObj[0] = infowindow;
                    });
                    // marker.addListener('mouseover', function () {
                    //     closeOtherInfo();
                    //     infowindow.open(marker.get('map'), marker);
                    //     InforObj[0] = infowindow;
                    // });
                    // marker.addListener('mouseout', function () {
                    //     closeOtherInfo();
                    //     infowindow.close();
                    //     InforObj[0] = infowindow;
                    // });
                }
            }

            function closeOtherInfo() {
                if (InforObj.length > 0) {
                    /* detach the info-window from the marker ... undocumented in the API docs */
                    InforObj[0].set("marker", null);
                    /* and close it */
                    InforObj[0].close();
                    /* blank the array */
                    InforObj.length = 0;
                }
            }

            function initMap() {
                map = new google.maps.Map(document.getElementById('map'), {
                    zoom: 4,
                    center: centerCords
                });
                addMarkerInfo();
            }
        </script>
    </head>

    <body>
        <h3>My Google Maps Demo</h3>
        <!--The div element for the map -->
        <div id="map"></div>

        <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY"></script>

    </body>

    </html>

From Google Map API samples:

function initialize() {
  var myOptions = {
    zoom: 10,
    center: new google.maps.LatLng(-33.9, 151.2),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }
  var map = new google.maps.Map(document.getElementById("map_canvas"),
                                myOptions);

  setMarkers(map, beaches);
}

/**
 * Data for the markers consisting of a name, a LatLng and a zIndex for
 * the order in which these markers should display on top of each
 * other.
 */
var beaches = [
  ['Bondi Beach', -33.890542, 151.274856, 4],
  ['Coogee Beach', -33.923036, 151.259052, 5],
  ['Cronulla Beach', -34.028249, 151.157507, 3],
  ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
  ['Maroubra Beach', -33.950198, 151.259302, 1]
];

function setMarkers(map, locations) {
  // Add markers to the map

  // Marker sizes are expressed as a Size of X,Y
  // where the origin of the image (0,0) is located
  // in the top left of the image.

  // Origins, anchor positions and coordinates of the marker
  // increase in the X direction to the right and in
  // the Y direction down.
  var image = new google.maps.MarkerImage('images/beachflag.png',
      // This marker is 20 pixels wide by 32 pixels tall.
      new google.maps.Size(20, 32),
      // The origin for this image is 0,0.
      new google.maps.Point(0,0),
      // The anchor for this image is the base of the flagpole at 0,32.
      new google.maps.Point(0, 32));
  var shadow = new google.maps.MarkerImage('images/beachflag_shadow.png',
      // The shadow image is larger in the horizontal dimension
      // while the position and offset are the same as for the main image.
      new google.maps.Size(37, 32),
      new google.maps.Point(0,0),
      new google.maps.Point(0, 32));
      // Shapes define the clickable region of the icon.
      // The type defines an HTML &lt;area&gt; element 'poly' which
      // traces out a polygon as a series of X,Y points. The final
      // coordinate closes the poly by connecting to the first
      // coordinate.
  var shape = {
      coord: [1, 1, 1, 20, 18, 20, 18 , 1],
      type: 'poly'
  };
  for (var i = 0; i < locations.length; i++) {
    var beach = locations[i];
    var myLatLng = new google.maps.LatLng(beach[1], beach[2]);
    var marker = new google.maps.Marker({
        position: myLatLng,
        map: map,
        shadow: shadow,
        icon: image,
        shape: shape,
        title: beach[0],
        zIndex: beach[3]
    });
  }
}

Accepted answer, rewritten in ES6:

$(document).ready(() => {
  const mapEl = $('#our_map').get(0); // OR document.getElementById('our_map');

  // Display a map on the page
  const map = new google.maps.Map(mapEl, { mapTypeId: 'roadmap' });

  const buildings = [
    {
      title: 'London Eye, London', 
      coordinates: [51.503454, -0.119562],
      info: 'carousel'
    },
    {
      title: 'Palace of Westminster, London', 
      coordinates: [51.499633, -0.124755],
      info: 'palace'
    }
  ];

  placeBuildingsOnMap(buildings, map);
});


const placeBuildingsOnMap = (buildings, map) => {
  // Loop through our array of buildings & place each one on the map  
  const bounds = new google.maps.LatLngBounds();
  buildings.forEach((building) => {
    const position = { lat: building.coordinates[0], lng: building.coordinates[1] }
    // Stretch our bounds to the newly found marker position
    bounds.extend(position);

    const marker = new google.maps.Marker({
      position: position,
      map: map,
      title: building.title
    });

    const infoWindow = new google.maps.InfoWindow();
    // Allow each marker to have an info window
    google.maps.event.addListener(marker, 'click', () => {
      infoWindow.setContent(building.info);
      infoWindow.open(map, marker);
    })

    // Automatically center the map fitting all markers on the screen
    map.fitBounds(bounds);
  })
})

Following from Daniel Vassallo's answer, here is a version that deals with the closure issue in a simpler way.

Since since all markers will have an individual InfoWindow and since JavaScript doesn't care if you add extra properties to an object, all you need to do is add an InfoWindow to the Marker's properties and then call the .open() on the InfoWindow from itself!

Edit: With enough data, the pageload could take a lot of time, so rather than construction the InfoWindow with the marker, the construction should happen only when needed. Note that any data used to construct the InfoWindow must be appended to the Marker as a property (data). Also note that after the first click event, infoWindow will persist as a property of it's marker so the browser doesn't need to constantly reconstruct.

var locations = [
  ['Bondi Beach', -33.890542, 151.274856, 4],
  ['Coogee Beach', -33.923036, 151.259052, 5],
  ['Cronulla Beach', -34.028249, 151.157507, 3],
  ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
  ['Maroubra Beach', -33.950198, 151.259302, 1]
];

var map = new google.maps.Map(document.getElementById('map'), {
  center: new google.maps.LatLng(-33.92, 151.25)
});

for (i = 0; i < locations.length; i++) {  
  marker = new google.maps.Marker({
    position: new google.maps.LatLng(locations[i][1], locations[i][2]),
    map: map,
    data: {
      name: locations[i][0]
    }
  });
  marker.addListener('click', function() {
    if(!this.infoWindow) {
      this.infoWindow = new google.maps.InfoWindow({
        content: this.data.name;
      });
    }
    this.infoWindow.open(map,this);
  })
}

Here is a nearly complete example javascript function that will allow multiple markers defined in a JSONObject.

It will only display the markers that are with in the bounds of the map.

This is important so you are not doing extra work.

You can also set a limit to the markers so you are not showing an extreme amount of markers (if there is a possibility of a thing in your usage);

it will also not display markers if the center of the map has not changed more than 500 meters.
This is important because if a user clicks on the marker and accidentally drags the map while doing so you don't want the map to reload the markers.

I attached this function to the idle event listener for the map so markers will show only when the map is idle and will redisplay the markers after a different event.

In action screen shot there is a little change in the screen shot showing more content in the infowindow. enter image description here pasted from pastbin.com

_x000D_
_x000D_
<script src="//pastebin.com/embed_js/uWAbRxfg"></script>
_x000D_
_x000D_
_x000D_


The recent simplest after modification in current map markers and clusterer algorithm:

Modification on: https://developers.google.com/maps/documentation/javascript/marker-clustering[![enter image description here]1]1

<!DOCTYPE Html>
<html>

<head>
<meta Content-Security-Policy="default-src  'self'; script-src 'self' 'unsafe-eval' https://*/;">
<link type="text/css" href="http://www.mapsmarker.com/wp-content/uploads/leaflet-maps-marker-icons/bar_coktail.png">
<link rel="icon" href="data:,">
<title>App</title>
</head>
<style type="text/css">
   #map {
    height: 500
}
</style>

<body>
<div id='map' style="width:100%; height:400px"></div>
<script type='text/javascript'>
    function initMap() {
        maps = new google.maps.Map(document.getElementById('map'), {
            center: new google.maps.LatLng(12.9824855, 77.637094),
            zoom: 5,
            disableDefaultUI: false,
            mapTypeId: google.maps.MapTypeId.HYBRID
        });
        var labels='ABCDEFGHIJKLMNOPQRSTUVWXYZ';
        var markerImage = 'http://www.mapsmarker.com/wp-content/uploads/leaflet-maps-marker-icons/bar_coktail.png';
        marker = locations.map(function (location, i) {
            return new google.maps.Marker({
                position: new google.maps.LatLng(location.lat, location.lng),
                map: maps,
                title: "Map",
                label: labels[i % labels.length],
                icon: markerImage
            });
        });

        var markerCluster = new MarkerClusterer(maps, marker, {
            imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m'
        });
    }
    var locations = [
            { lat: 12.9824855, lng: 77.637094},
            { lat: 11.9824855, lng: 77.154312 },
            { lat: 12.8824855, lng: 77.637094},
            { lat: 10.8824855, lng: 77.054312 },
            { lat: 12.9824855, lng: 77.637094},
            { lat: 11.9824855, lng: 77.154312 },
            { lat: 12.8824855, lng: 77.637094},
            { lat: 13.8824855, lng: 77.054312 },
            { lat: 14.9824855, lng: 54.637094},
            { lat: 15.9824855, lng: 54.154312 },
            { lat: 16.8824855, lng: 53.637094},
            { lat: 17.8824855, lng: 52.054312 },
            { lat: 18.9824855, lng: 51.637094},
            { lat: 19.9824855, lng: 69.154312 },
            { lat: 20.8824855, lng: 68.637094},
            { lat: 21.8824855, lng: 67.054312 },
            { lat: 12.9824855, lng: 76.637094},
            { lat: 11.9824855, lng: 75.154312 },
            { lat: 12.8824855, lng: 74.637094},
            { lat: 10.8824855, lng: 74.054312 },
            { lat: 12.9824855, lng: 73.637094},
            { lat: 3.9824855, lng: 72.154312 },
            { lat: 2.8824855, lng: 71.637094},
            { lat: 1.8824855, lng: 70.054312 }
        ];

</script>
<script src="https://unpkg.com/@google/[email protected]/dist/markerclustererplus.min.js">
</script>
<script src="https:maps.googleapis.com/maps/api/js?key=AIzaSyDWu6_Io9xA1oerfOxE77YAv31etN4u3Dw&callback=initMap">
</script>
<script type='text/javascript'></script>

This is the working example map image

var arr = new Array();
    function initialize() { 
        var i;  
        var Locations = [
                {
                  lat:48.856614, 
                  lon:2.3522219000000177, 
                  address:'Paris',
                  gval:'25.5',
                  aType:'Non-Commodity',
                  title:'Paris',
                  descr:'Paris'           
                },        
                    {
                  lat: 55.7512419, 
                  lon: 37.6184217,
                  address:'Moscow',
                  gval:'11.5',
                  aType:'Non-Commodity',
                  title:'Moscow',
                  descr:'Moscow Airport'              
                },     

                {
              lat:-9.481553000000002, 
              lon:147.190242, 
              address:'Port Moresby',
              gval:'1',
              aType:'Oil',
              title:'Papua New Guinea',
              descr:'Papua New Guinea 123123123'              
            },
            {
           lat:20.5200,
           lon:77.7500,
           address:'Indore',
            gval:'1',
            aType:'Oil',
            title:'Indore, India',
            descr:'Airport India'
        }
    ];

    var myOptions = {
        zoom: 2,
        center: new google.maps.LatLng(51.9000,8.4731),
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };

    var map = new google.maps.Map(document.getElementById("map"), myOptions);

    var infowindow =  new google.maps.InfoWindow({
        content: ''
    });

    for (i = 0; i < Locations.length; i++) {
            size=15;        
            var img=new google.maps.MarkerImage('marker.png',           
                new google.maps.Size(size, size),
                new google.maps.Point(0,0),
                new google.maps.Point(size/2, size/2)
           );

        var marker = new google.maps.Marker({
            map: map,
            title: Locations[i].title,
            position: new google.maps.LatLng(Locations[i].lat, Locations[i].lon),           
                icon: img
        });

        bindInfoWindow(marker, map, infowindow, "<p>" + Locations[i].descr + "</p>",Locations[i].title);  

    }

}

function bindInfoWindow(marker, map, infowindow, html, Ltitle) { 
    google.maps.event.addListener(marker, 'mouseover', function() {
            infowindow.setContent(html); 
            infowindow.open(map, marker); 

    });
    google.maps.event.addListener(marker, 'mouseout', function() {
        infowindow.close();

    }); 
} 

Full working example. You can just copy, paste and use.


Add a marker in your program is very easy. You just may add this code:

var marker = new google.maps.Marker({
  position: myLatLng,
  map: map,
  title: 'Hello World!'
});

The following fields are particularly important and commonly set when you construct a marker:

  • position (required) specifies a LatLng identifying the initial location of the marker. One way of retrieving a LatLng is by using the Geocoding service.
  • map (optional) specifies the Map on which to place the marker. If you do not specify a map on construction of the marker, the marker is created but is not attached to (or displayed on) the map. You may add the marker later by calling the marker's setMap() method.

Note, in the example, the title field set the marker's title who will appear as a tooltip.

You may consult the Google api documenation here.


This is a complete example to set one marker in a map. Be care full, you have to replace YOUR_API_KEY by your google API key:

<!DOCTYPE html>
<html>
<head>
   <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
   <meta charset="utf-8">
   <title>Simple markers</title>
<style>
  /* Always set the map height explicitly to define the size of the div
   * element that contains the map. */
  #map {
    height: 100%;
  }
  /* Optional: Makes the sample page fill the window. */
  html, body {
    height: 100%;
    margin: 0;
    padding: 0;
  }
</style>
</head>
<body>
 <div id="map"></div>
<script>

  function initMap() {
    var myLatLng = {lat: -25.363, lng: 131.044};

    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 4,
      center: myLatLng
    });

    var marker = new google.maps.Marker({
      position: myLatLng,
      map: map,
      title: 'Hello World!'
    });
  }
</script>
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
</script>


Now, if you want to plot markers of an array in a map, you should do like this:

var locations = [
  ['Bondi Beach', -33.890542, 151.274856, 4],
  ['Coogee Beach', -33.923036, 151.259052, 5],
  ['Cronulla Beach', -34.028249, 151.157507, 3],
  ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
  ['Maroubra Beach', -33.950198, 151.259302, 1]
];

function initMap() {
  var myLatLng = {lat: -33.90, lng: 151.16};

  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 10,
    center: myLatLng
    });

  var count;

  for (count = 0; count < locations.length; count++) {  
    new google.maps.Marker({
      position: new google.maps.LatLng(locations[count][1], locations[count][2]),
      map: map,
      title: locations[count][0]
      });
   }
}

This example give me the following result:

enter image description here


You can, also, add an infoWindow in your pin. You just need this code:

var marker = new google.maps.Marker({
    position: new google.maps.LatLng(locations[count][1], locations[count][2]),
    map: map
    });

marker.info = new google.maps.InfoWindow({
    content: 'Hello World!'
    });

You can have the Google's documentation about infoWindows here.


Now, we can open the infoWindow when the marker is "clik" like this:

var marker = new google.maps.Marker({
     position: new google.maps.LatLng(locations[count][1], locations[count][2]),
     map: map
     });

marker.info = new google.maps.InfoWindow({
     content: locations [count][0]
     });


google.maps.event.addListener(marker, 'click', function() {  
    // this = marker
    var marker_map = this.getMap();
    this.info.open(marker_map, this);
    // Note: If you call open() without passing a marker, the InfoWindow will use the position specified upon construction through the InfoWindowOptions object literal.
            });

Note, you can have some documentation about Listener here in google developer.


And, finally, we can plot an infoWindow in a marker if the user click on it. This is my complete code:

<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Info windows</title>
    <style>
    /* Always set the map height explicitly to define the size of the div
    * element that contains the map. */
    #map {
        height: 100%;
    }
    /* Optional: Makes the sample page fill the window. */
    html, body {
        height: 100%;
        margin: 0;
        padding: 0;
    }
    </style>
</head>
<body>
    <div id="map"></div>
    <script>

    var locations = [
        ['Bondi Beach', -33.890542, 151.274856, 4],
        ['Coogee Beach', -33.923036, 151.259052, 5],
        ['Cronulla Beach', -34.028249, 151.157507, 3],
        ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
        ['Maroubra Beach', -33.950198, 151.259302, 1]
    ];


    // When the user clicks the marker, an info window opens.

    function initMap() {
        var myLatLng = {lat: -33.90, lng: 151.16};

        var map = new google.maps.Map(document.getElementById('map'), {
            zoom: 10,
            center: myLatLng
            });

        var count=0;


        for (count = 0; count < locations.length; count++) {  

            var marker = new google.maps.Marker({
                position: new google.maps.LatLng(locations[count][1], locations[count][2]),
                map: map
                });

            marker.info = new google.maps.InfoWindow({
                content: locations [count][0]
                });


            google.maps.event.addListener(marker, 'click', function() {  
                // this = marker
                var marker_map = this.getMap();
                this.info.open(marker_map, this);
                // Note: If you call open() without passing a marker, the InfoWindow will use the position specified upon construction through the InfoWindowOptions object literal.
                });
        }
    }
    </script>
    <script async defer
    src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
    </script>
</body>
</html>

Normally, you should have this result:

Your result


Here is another version I wrote to save map real estate, that places the infowindow pointer on the actual lat and long of the marker, while temporarily hiding the marker while the infowindow is being displayed.

It also does away with the standard 'marker' assignment and speeds up processing by directly assigning the new marker to the markers array on the markers creation. Note however, that additional properties have been added to both the marker and the infowindow, so this approach is a tad unconventional... but that's me!

It is never mentioned in these infowindow questions, that the standard infowindow IS NOT placed at the lat and lng of the marker point, but rather at the top of the marker image. The marker visibility must be hidden for this to work, otherwise the Maps API will shove the infowindow anchor back to the top of the marker image again.

Reference to the markers in the 'markers' array are created immediately upon marker declaration for any additional processing tasks that may be desired later(hiding/showing, grabbing the coords,etc...). This saves the additional step of assigning the marker object to 'marker', and then pushing the 'marker' to the markers array... a lot of unnecessary processing in my book.

Anyway, a different take on infowindows, and hope it helps to inform and inspire you.

    var locations = [
      ['Bondi Beach', -33.890542, 151.274856, 4],
      ['Coogee Beach', -33.923036, 151.259052, 5],
      ['Cronulla Beach', -34.028249, 151.157507, 3],
      ['Manly Beach', -33.80010128657071, 151.28747820854187, 2],
      ['Maroubra Beach', -33.950198, 151.259302, 1]
    ];
    var map;
    var markers = [];

    function init(){
      map = new google.maps.Map(document.getElementById('map_canvas'), {
        zoom: 10,
        center: new google.maps.LatLng(-33.92, 151.25),
        mapTypeId: google.maps.MapTypeId.ROADMAP
      });

      var num_markers = locations.length;
      for (var i = 0; i < num_markers; i++) {  
        markers[i] = new google.maps.Marker({
          position: {lat:locations[i][1], lng:locations[i][2]},
          map: map,
          html: locations[i][0],
          id: i,
        });

        google.maps.event.addListener(markers[i], 'click', function(){
          var infowindow = new google.maps.InfoWindow({
            id: this.id,
            content:this.html,
            position:this.getPosition()
          });
          google.maps.event.addListenerOnce(infowindow, 'closeclick', function(){
            markers[this.id].setVisible(true);
          });
          this.setVisible(false);
          infowindow.open(map);
        });
      }
    }

google.maps.event.addDomListener(window, 'load', init);

Here is a working JSFiddle

Additional Note
You will notice in this given Google example data a fourth place in the 'locations' array with a number. Given this in the example, you could also use this value for the marker id in place of the current loop value, such that...

var num_markers = locations.length;
for (var i = 0; i < num_markers; i++) {  
  markers[i] = new google.maps.Marker({
    position: {lat:locations[i][1], lng:locations[i][2]},
    map: map,
    html: locations[i][0],
    id: locations[i][3],
  });
};

Here is an example of multiple markers in Reactjs.

enter image description here

Below is the map component

import React from 'react';
import PropTypes from 'prop-types';
import { Map, InfoWindow, Marker, GoogleApiWrapper } from 'google-maps-react';

const MapContainer = (props) => {
  const [mapConfigurations, setMapConfigurations] = useState({
    showingInfoWindow: false,
    activeMarker: {},
    selectedPlace: {}
  });

  var points = [
    { lat: 42.02, lng: -77.01 },
    { lat: 42.03, lng: -77.02 },
    { lat: 41.03, lng: -77.04 },
    { lat: 42.05, lng: -77.02 }
  ]
  const onMarkerClick = (newProps, marker) => {};

  if (!props.google) {
    return <div>Loading...</div>;
  }

  return (
    <div className="custom-map-container">
      <Map
        style={{
          minWidth: '200px',
          minHeight: '140px',
          width: '100%',
          height: '100%',
          position: 'relative'
        }}
        initialCenter={{
          lat: 42.39,
          lng: -72.52
        }}
        google={props.google}
        zoom={16}
      >
        {points.map(coordinates => (
          <Marker
            position={{ lat: coordinates.lat, lng: coordinates.lng }}
            onClick={onMarkerClick}
            icon={{
              url: 'https://res.cloudinary.com/mybukka/image/upload/c_scale,r_50,w_30,h_30/v1580550858/yaiwq492u1lwuy2lb9ua.png',
            anchor: new google.maps.Point(32, 32), // eslint-disable-line
            scaledSize: new google.maps.Size(30, 30)  // eslint-disable-line
            }}
            name={name}
          />))}
        <InfoWindow
          marker={mapConfigurations.activeMarker}
          visible={mapConfigurations.showingInfoWindow}
        >
          <div>
            <h1>{mapConfigurations.selectedPlace.name}</h1>
          </div>
        </InfoWindow>
      </Map>
    </div>
  );
};

export default GoogleApiWrapper({
  apiKey: process.env.GOOGLE_API_KEY,
  v: '3'
})(MapContainer);

MapContainer.propTypes = {
  google: PropTypes.shape({}).isRequired,
};


Here is another example of multiple markers loading with a unique title and infoWindow text. Tested with the latest google maps API V3.11.

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
        <title>Multiple Markers Google Maps</title>
        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
        <script src="https://maps.googleapis.com/maps/api/js?v=3.11&sensor=false" type="text/javascript"></script>
        <script type="text/javascript">
        // check DOM Ready
        $(document).ready(function() {
            // execute
            (function() {
                // map options
                var options = {
                    zoom: 5,
                    center: new google.maps.LatLng(39.909736, -98.522109), // centered US
                    mapTypeId: google.maps.MapTypeId.TERRAIN,
                    mapTypeControl: false
                };

                // init map
                var map = new google.maps.Map(document.getElementById('map_canvas'), options);

                // NY and CA sample Lat / Lng
                var southWest = new google.maps.LatLng(40.744656, -74.005966);
                var northEast = new google.maps.LatLng(34.052234, -118.243685);
                var lngSpan = northEast.lng() - southWest.lng();
                var latSpan = northEast.lat() - southWest.lat();

                // set multiple marker
                for (var i = 0; i < 250; i++) {
                    // init markers
                    var marker = new google.maps.Marker({
                        position: new google.maps.LatLng(southWest.lat() + latSpan * Math.random(), southWest.lng() + lngSpan * Math.random()),
                        map: map,
                        title: 'Click Me ' + i
                    });

                    // process multiple info windows
                    (function(marker, i) {
                        // add click event
                        google.maps.event.addListener(marker, 'click', function() {
                            infowindow = new google.maps.InfoWindow({
                                content: 'Hello, World!!'
                            });
                            infowindow.open(map, marker);
                        });
                    })(marker, i);
                }
            })();
        });
        </script>
    </head>
    <body>
        <div id="map_canvas" style="width: 800px; height:500px;"></div>
    </body>
</html>

Screenshot of 250 Markers:

Google Maps API V3.11 with Multiple Markers

It will automatically randomize the Lat/Lng to make it unique. This example will be very helpful if you want to test 500, 1000, xxx markers and performance.


  • I know this answer is very much late. But I wish this will help other developers also. :-)
  • The Following code will add multiple markers on the google map with the information window.
  • And this code can be used to plot any number of markers on the map.
  • Please put your Google Map API key to the correct position of this code. (I have marked that as "Your API Key")

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>My Google Map</title>
    <style>
        #map{
            height: 600px;
            width: 100%;
        }
    </style>
</head>
<body>

<h1>My Google Map`</h1>
<div id="map"></div>


    <script>
        function initMap(){
          //Map options
            var options = {
                zoom:9,
                center:{lat:42.3601, lng:-71.0589}
            }
            // new map
            var map = new google.maps.Map(document.getElementById('map'), options);
            // customer marker
            var iconBase = 'https://maps.google.com/mapfiles/kml/shapes/parking_lot_maps.png';
            //array of Marrkeers
            var markers = [
              {
                coords:{lat: 42.4668, lng: -70.9495},img:iconBase,con:'<h3> This Is your Content <h3>'
              },
              {
                coords:{lat: 42.8584, lng: -70.9300},img:iconBase,con:'<h3> This Is your Content <h3>'
              },
              {
                coords:{lat: 42.7762, lng: -71.0773},img:iconBase,con:'<h3> This Is your Content <h3>'
              }
            ];

            //loopthrough markers
            for(var i = 0; i <markers.length; i++){
              //add markeers
              addMarker(markers[i]);
            }

            //function for the plotting markers on the map
            function addMarker (props){
              var marker = new google.maps.Marker({
                position: props.coords,
                map:map,
                icon:props.img
              });
              var infoWindow = new google.maps.InfoWindow({
                content:props.con,
              });
              marker.addListener("click", () => {
                infoWindow.open(map, marker);
              });
            }
        }
    </script>

    <script
      src="https://maps.googleapis.com/maps/api/js?key=**YourAPIKey**&callback=initMap"
      defer
    ></script>

</body>
</html>

I thought I would put this here as it appears to be a popular landing point for those starting to use Google Maps API's. Multiple markers rendered on the client side is probably the downfall of many mapping applications performance wise. It is difficult to benchmark, fix and in some cases even establish there is an issue (due to browser implementation differences, hardware available to the client, mobile devices, the list goes on).

The simplest way to begin to address this issue is to use a marker clustering solution. The basic idea is to group geographically similar locations into a group with the number of points displayed. As the user zooms into the map these groups expand to reveal individual markers beneath.

Perhaps the simplest to implement is the markerclusterer library. A basic implementation would be as follows (after library imports):

<script type="text/javascript">
  function initialize() {
    var center = new google.maps.LatLng(37.4419, -122.1419);

    var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 3,
      center: center,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });

    var markers = [];
    for (var i = 0; i < 100; i++) {
      var location = yourData.location[i];
      var latLng = new google.maps.LatLng(location.latitude,
          location.longitude);
      var marker = new google.maps.Marker({
        position: latLng
      });
      markers.push(marker);
    }
    var markerCluster = new MarkerClusterer(map, markers);
  }
  google.maps.event.addDomListener(window, 'load', initialize);
</script>

The markers instead of being added directly to the map are added to an array. This array is then passed to the library which handles complex calculation for you and attached to the map.

Not only do these implementations massively increase client side performance but they also in many cases lead to a simpler and less cluttered UI and easier digestion of data on larger scales.

Other implementations are available from Google.

Hope this aids some of those newer to the nuances of mapping.


Examples related to javascript

need to add a class to an element How to make a variable accessible outside a function? Hide Signs that Meteor.js was Used How to create a showdown.js markdown extension Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Summing radio input values How to execute an action before close metro app WinJS javascript, for loop defines a dynamic variable name Getting all files in directory with ajax

Examples related to google-maps

GoogleMaps API KEY for testing Google Maps shows "For development purposes only" java.lang.NoClassDefFoundError:failed resolution of :Lorg/apache/http/ProtocolVersion How to import JSON File into a TypeScript file? Googlemaps API Key for Localhost Getting "Cannot call a class as a function" in my React Project ERROR: Google Maps API error: MissingKeyMapError This page didn't load Google Maps correctly. See the JavaScript console for technical details Google Maps API warning: NoApiKeys ApiNotActivatedMapError for simple html page using google-places-api

Examples related to google-maps-api-3

Google Maps shows "For development purposes only" Googlemaps API Key for Localhost ERROR: Google Maps API error: MissingKeyMapError Google Maps API warning: NoApiKeys Google Maps JavaScript API RefererNotAllowedMapError This API project is not authorized to use this API. Please ensure that this API is activated in the APIs Console TypeError: window.initMap is not a function Google maps Marker Label with multiple characters Google Maps how to Show city or an Area outline How to use SVG markers in Google Maps API v3