Google Maps refresh traffic layer

Question

In my Rails app, the background consists of a fullscreen div with Google Maps and a traffic layer. This is what gets called on page load:

$(function () {  
         


        

Answer 1

A setInterval over the whole initialize routine got me the refreshing that I desired. options.ts_google_map_traffic_refresh_milliseconds is set to the milliseconds you desire.

 setInterval(_ts_map_initialize, options.ts_google_map_traffic_refresh_milliseconds);

    function _ts_map_initialize(){              
        console.log('function _ts_map_initialize()')
        var myLatlng = new google.maps.LatLng(options.ts_google_map_traffic_latHome,options.ts_google_map_traffic_lonHome);
        var myOptions = {
          zoom: ts_int_zoomLevel,
          center: myLatlng,
          panControl: false,              
          zoomControl: false,
          streetViewControl: false,
          overviewMapControl: false,              
          mapTypeId: google.maps.MapTypeId.ROADMAP,
          styles:[{
              featureType:"poi",
              elementType:"labels",
              stylers:[{
                  visibility:"off"
              }]
          }]              
        }
        map = new google.maps.Map(document.getElementById('ts_google_map_traffic_canvas'), myOptions);
        defaultBounds = map.getBounds();

        trafficLayer = new  google.maps.TrafficLayer(); //add the layer - don't view it unless user toggles button  

        trafficLayer.setMap(map);

}

enter code here

Answer 2

So I found the answer. Apparently you cannot update the map with a new overlay while inside the timeOut function. I do not know why exactly (as for instance a 'alert()' does show while inside the function). I solved it using a switch statement in the updateOnTrafficMap function, so that once every minute the layout disappears, and immediately reappears using another timeOut (set to 1 ms).

function updateMap()  {
  // the following creates a Google Map with zoom level 10 and the LatLong coordinates
  // stated below
  var latlng = new google.maps.LatLng(52.053335, 4.917755);
  var myOptions = {
    zoom: 10,
    center: latlng,
    disableDefaultUI: true,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  };
  var map = new google.maps.Map(document.getElementById("google_map"), myOptions);
  updateTrafficOnMap(map, null, 1);
}

function updateTrafficOnMap(map, trafficLayer, on)
{
  if(on == 0) {
    trafficLayer.setMap(null);
    setTimeout(function() { updateTrafficOnMap(map, null, 1) }, 1) 
  }
  if(on == 1) {
    var trafficLayer2 = new google.maps.TrafficLayer();
    trafficLayer2.setMap(map);
    // after 300ms (or 5 minutes) update the traffic map
    setTimeout(function() { updateTrafficOnMap(map, trafficLayer2, 0)}, 300000)
  }
}

On document load you call the updateMap() function, and you should have a DIV with id "google_map" to display the map in of course.

Answer 3

This worked for me:

var _mainMap = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
var _gmapTrLayer = new google.maps.TrafficLayer();
_gmapTrLayer.setMap(_mainMap);
setInterval(refreshGmapsTrafficLayer, 60000); // runs every minute

function refreshGmapsTrafficLayer() {
    _gmapTrLayer.setMap(null);
    _gmapTrLayer.setMap(_mainMap);
}