title: Removing a layer in OpenLayers
body: <p>I don't know why this isn't working. I would assume the answer is really simple. I need to remove a layer before adding a new one. </p>
  
  <pre><code>                     if (graphic) {
          window.map.removeLayer(graphic);
      }
      var graphic = new OpenLayers.Layer.Image(
          'Sightline'+''+SC,
          url,
          new OpenLayers.Bounds(derWesten[0].firstChild.nodeValue,derSueden[0].firstChild.nodeValue,derOsten[0].firstChild.nodeValue, derNorden[0].firstChild.nodeValue),
          new OpenLayers.Size(0,0),
          options
      );
  
      window.map.addLayer(graphic);   
  </code></pre>
  
  <p>It just keeps piling on the layers and not removing any. Any help?</p>