Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've just started learning Cloudmade Web Maps API. I'm at marker clustering, and I'm facing a strange problem; whenever I try accessing the page below, content of elements must consist of well-formed character... trace is shown, and the map doesn't render. My code is shown below:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "">
<html xmlns="" xml:lang="en">
  <script type="text/javascript" src=""></script>
<script type="text/javascript" src=""></script>
<title>CloudMade Marker Clustering</title>

<div id="cm-example" style="width: 500px; height: 500px"></div>

<script type="text/javascript">
  var cloudmade = new CM.Tiles.CloudMade.Web({key: 'API-KEY'});
  var map = new CM.Map('cm-example', cloudmade);

  map.setCenter(new CM.LatLng(51.50874, 22.76367), 4);

  var markers = [];
  for (var i = 0; i < samplePoints.length; i++) {
    markers.push(new CM.Marker(new CM.LatLng(samplePoints[i][0], samplePoints[i][1])));

  var clusterer = new CM.MarkerClusterer(map, {clusterRadius: 70});


It appears simple, but I can't spot the problem. Any assistance will be appreciated. Thanks in advance.

share|improve this question

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.