Plotting several markers on google maps using nodejs

Question

I want to plot several markers on a Google Map. I'm using NodeJS to fetch the markers and HTML as front end.

Here's the node script:

app.get('/blood',function(req,res){
  var l = [];
  l.push(['1',23.567,88.645,1]);
  l.push(['2',23.560,88.647,2]);
  console.log(JSON.stringify(l));
  res.render('../public/blood.ejs',{ layout: false, lat:23.567, lon:88.678, l:l});
});

Here's the HTML:

<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-canvas'), {
      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));
    }
      }
      google.maps.event.addDomListener(window, 'load', initialize);
    </script>

I have used only static locations in the code. How can i dynamically use the markers on the Google Maps?

Kindly suggest. Thanks.

EDIT:

It should look like: enter image description here

Instead it does not render the map:

enter image description here

Yalamber · Answer 1 · 2015-03-24T06:21:48.100

1

It seems like you are passing locations array to view. But i am quite not sure what first and last items that you are pushing in array are.

l.push(['1',23.567,88.645,1]);//may be you will need to push items in correct format here.

Anyway after passing l array to view you could simply assign it to markers variable in view file:

<script type="text/javascript">
      function initialize() {
        var locations = <%- l %>

    var 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 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));
    }
      }
      google.maps.event.addDomListener(window, 'load', initialize);
    </script>

edited Mar 24 '15 at 06:21

answered Mar 24 '15 at 06:05

Yalamber

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This is mostly correct, but when printing the object in the HTML file, you should use `<%- ... %>` rather than `<%= ... %>` [(source)](http://stackoverflow.com/questions/13788314/express-and-ejs-to-render-a-json) - this will print the object as-is (which will be valid javascript) as opposed to HTML (which is not) – ttarik Mar 24 '15 at 06:17
@Yalamber I have tried the above code, thanks for it. And i have also replaced ['name',lat,long,serial_no] with just [lat,long] format and stiil the map is not rendered. – Abhishek Dey Mar 24 '15 at 06:40
however if i pass `<%- l %>` to a string it shows correctly. :( – Abhishek Dey Mar 24 '15 at 06:44
According to this `position: new google.maps.LatLng(locations[i][1], locations[i][2]),` your location array element you are passing lat and lng in second and third item in your array. so you should keep that as it is or simply do `l.push(['Bondi Beach', -33.890542, 151.274856, 4])` this way – Yalamber Mar 24 '15 at 09:23

Plotting several markers on google maps using nodejs

1 Answers1