How to Dynamically refresh / reload a KML layer in OpenLayers

Question

I have previously asked this question to no avail so I thought putting this up here would be a good idea.

Here is an example on:

How to Refresh / Reload a KML layer in OpenLayers. Dynamic KML Layer. See my answer below.

TLDR: See my answer below.

zearth · Accepted Answer · 2011-07-25 03:58:20Z

Figured seen as it was hard enough for me to find information on this I would add this:

1)

Create the KML Layer:

            //Define your KML layer
            var MyKmlLayer= new OpenLayers.Layer.Vector("This Is My KML Layer", {
                //Set your projection and strategies//
                projection: new OpenLayers.Projection("EPSG:4326"),
                strategies: [new OpenLayers.Strategy.Fixed()],
                //set the protocol with a url//
                protocol: new OpenLayers.Protocol.HTTP({
                    //set the url to your variable//
                    url: mykmlurl,
                    //format this layer as KML//
                    format: new OpenLayers.Format.KML({
                        //maxDepth is how deep it will follow network links//
                        maxDepth: 1,
                        //extract styles from the KML Layer//
                        extractStyles: true,
                        //extract attributes from the KML Layer//
                        extractAttributes: true
                    })
                })
            });

2)

Set the URL for the KML Layer:

//note that I have host equal to location//   //Math.Random will stop caching//
var mykmlurl= 'http://' + host + '/KML?key=' + Math.random();

3)

Set the interval in which to refresh your layer:

           //function called// //timer// //layer to refresh//
window.setInterval(UpdateKmlLayer, 5000, MyKmlLayer);

4)

The function to update the layer:

            function UpdateKmlLayer(layer) {
                //setting loaded to false unloads the layer//
                layer.loaded = false;
                //setting visibility to true forces a reload of the layer//
                layer.setVisibility(true);
                //the refresh will force it to get the new KML data//
                layer.refresh({ force: true, params: { 'key': Math.random()} });
                //- <3 from Thqr -//
            }

Hopes this makes it easier for some others out there. Good luck.

What if your KML is local or on a networked drive?

Furlong
– Furlong

2010-11-08 21:15:27 +00:00
Commented Nov 8, 2010 at 21:15 — Furlong
– Furlong, Commented Nov 8, 2010 at 21:15

zearth · Accepted Answer · 2011-07-25 03:58:25Z

I have been putzing around with this to no avail. Would someone mind taking a look at my code and telling me what I am doing wrong? Thank you!

<html>
<head>
<title>Test</title>
<link rel="stylesheet" href="http://openlayers.org/api/theme/default/style.css" type="text/css" />
<link rel="stylesheet" href="http://openlayers.org/dev/examples/style.css" type="text/css" />
<script src='http://maps.google.com/maps?file=api&amp;v=2&amp;key=ABQIAAAAl9RMqSzhPUXAfeBCXOussRTQDbvAygy0cfGJr8dEMAYKf3RWNBQqP9mjKIsqTfmAlz5LOJ3Xpy5s4w'></script>
<script src="http://openlayers.org/api/OpenLayers.js"></script>
<script type="text/javascript">

  var map;

  function init() {
    // Create the map object
    map = new OpenLayers.Map('map');
    // Create a Google layer
    var gmap = new OpenLayers.Layer.Google(
        "Google Streets", // the default
        {numZoomLevels: 20}
    );
    // Add layer to map
    map.addLayer(gmap);

    map.setCenter(new OpenLayers.LonLat(-112.1161, 33.6636), 13);         
  }

  var MyKmlLayer= new OpenLayers.Layer.Vector("This Is My KML Layer", {
            //Set your projection and strategies//
            projection: new OpenLayers.Projection("EPSG:4326"),
            strategies: [new OpenLayers.Strategy.Fixed()],
            //set the protocol with a url//
            protocol: new OpenLayers.Protocol.HTTP({
                //set the url to your variable//
                url: C:/Users/person/desktop/test.kml,
                //format this layer as KML//
                format: new OpenLayers.Format.KML({
                    //maxDepth is how deep it will follow network links//
                    maxDepth: 1,
                    //extract styles from the KML Layer//
                    extractStyles: true,
                    //extract attributes from the KML Layer//
                    extractAttributes: true
                })
            })
        });

    var proposedanchorpositionurl = 'http://' + host + '/KML?key=' + Math.random();

    window.setInterval(UpdateKmlLayer, 5000, MyKmlLayer);

    function UpdateKmlLayer(layer) {
            //setting loaded to false unloads the layer//
            layer.loaded = false;
            //setting visibility to true forces a reload of the layer//
            layer.setVisibility(true);
            //the refresh will force it to get the new KML data//
            layer.refresh({ force: true, params: { 'key': Math.random()} });
            //- <3 from Thqr -//
        }
</script>
</head>
<body onload="init()">
<h1 id="title">test</h1>
<div id="map" class=""></div>
</body>
</html>

So sorry, I had to correct your imperfect codes. Should run this time.

erilem · Accepted Answer · 2012-04-17 05:23:22Z

1

You may want to look at the Refresh strategy. http://dev.openlayers.org/releases/OpenLayers-2.11/doc/apidocs/files/OpenLayers/Strategy/Refresh-js.html

answered Apr 17, 2012 at 5:23

erilem

2,13915 silver badges14 bronze badges

Add a comment |

sphvn · Accepted Answer · 2010-11-09 02:35:18Z

untested but something like this?

<script src="http://openlayers.org/api/OpenLayers.js"></script>
<script type="text/javascript">

  var map;

  function init() {
    // Create the map object
    map = new OpenLayers.Map('map');
    // Create a Google layer
    var gmap = new OpenLayers.Layer.Google(
        "Google Streets", // the default
        {numZoomLevels: 20}
    );
    // Add layer to map
    map.addLayer(gmap);

    map.setCenter(new OpenLayers.LonLat(-112.1161, 33.6636), 13);         


  var KMLURL = 'C:/Users/person/desktop/test.kml?' + Math.random();

  var MyKmlLayer= new OpenLayers.Layer.Vector("This Is My KML Layer", {
            //Set your projection and strategies//
            projection: new OpenLayers.Projection("EPSG:4326"),
            strategies: [new OpenLayers.Strategy.Fixed()],
            //set the protocol with a url//
            protocol: new OpenLayers.Protocol.HTTP({
                //set the url to your variable//
                url: KMLURL,
                //format this layer as KML//
                format: new OpenLayers.Format.KML({
                    //maxDepth is how deep it will follow network links//
                    maxDepth: 1,
                    //extract styles from the KML Layer//
                    extractStyles: true,
                    //extract attributes from the KML Layer//
                    extractAttributes: true
                })
            })
        });

    window.setInterval(UpdateKmlLayer, 5000, MyKmlLayer);

    function UpdateKmlLayer(layer) {
            //setting loaded to false unloads the layer//
            layer.loaded = false;
            //setting visibility to true forces a reload of the layer//
            layer.setVisibility(true);
            //the refresh will force it to get the new KML data//
            layer.refresh({ force: true, params: { 'key': Math.random()} });
            //- <3 from Thqr -//
        }
 }
</script>

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