[OpenLayers-Users] simple heatmap does not appear

Sun Oct 26 02:29:20 PDT 2014

Hello, 

I'm new to OpenLayers, anyway I'm trying to ad an heatmap. 

I tried two different ways to get the heatmap, the first one

<html><body>

  <div id="demoMap"></div>

  <script src=" <http://www.openlayers.org/api/OpenLayers.js>
http://www.openlayers.org/api/OpenLayers.js"></script>

  <script>

    map = new OpenLayers.Map("demoMap");

    map.addLayer(new OpenLayers.Layer.OSM());

    map.zoomToMaxExtent();

    var layer = new OpenLayers.Layer.OSM();

    heatmap = new OpenLayers.Layer.Heatmap("Heatmap Layer", map, layer,
null,

     {visible: true, radius: 15},

     {isBaseLayer: false, opacity: 0.3, projection: new
OpenLayers.Projection("EPSG:4326")});

    var lon, lat, c;

    for(var i=0; i<100; i++) {

     lon = i;

     lat = i;

     c = Math.floor(Math.random()*50);

     heatmap.addDataPoint(new OpenLayers.LonLat(lon, lat), c);

    }

  </script>

</body></html>

the second one 

<html><body>

  <div id="demoMap"></div>

  <script src=" <http://www.openlayers.org/api/OpenLayers.js>
http://www.openlayers.org/api/OpenLayers.js"></script>

  <script>

  var testData={

max: 46,

data: [{lat: 33.5363, lon:-117.044, count: 1}, {lat: 35.8278, lon:-78.6421,
count: 1}]

};

  layer = new OpenLayers.Layer.MapServer( "OpenLayers WMS",

" <http://labs.metacarta.com/wms/vmap0>
http://labs.metacarta.com/wms/vmap0", {layers: 'basic'}

);

  map = new OpenLayers.Map("demoMap");

  map.addLayer(new OpenLayers.Layer.OSM());

  map.zoomToMaxExtent();

  heatmap = new OpenLayers.Layer.Heatmap( "Heatmap Layer", map, layer,

{visible: true, radius:10}, {isBaseLayer: false, opacity: 0.3}

);

heatmap.setDataSet(testData);

map.addLayer(heatmap);

  </script>

</body></html>

I can only visualize the map without the heatmap layer. 

Thank you in advance for any suggestion. 

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