buffer.html 1.54 KB
<html>
<head>
  <title>Buffer example</title>
  <link rel="stylesheet" href="http://www.openlayers.org/api/2.11/theme/default/style.css" type="text/css" />
  
  <script src="http://www.openlayers.org/api/2.11/OpenLayers.js"></script>

  <script type="text/javascript" src="https://github.com/bjornharrtell/jsts/raw/master/lib/javascript.util.js"></script>
  <script type="text/javascript" src="https://github.com/bjornharrtell/jsts/raw/master/lib/jsts.js"></script>

<script type="text/javascript">
  function init() {
    var reader = new jsts.io.WKTReader();

    var input = reader.read('POLYGON ((80 300, 280 300, 280 80, 80 80, 80 300), (260 280, 180 200, 100 280, 100 100, 260 100, 260 280))');

    var buffer = input.buffer(20);
    
    var map = new OpenLayers.Map('map', {
      maxExtent: new OpenLayers.Bounds(0, 0, 300, 300),
      maxResolution: 100,
      units: 'm',
      controls: [new OpenLayers.Control.MousePosition(), new OpenLayers.Control.Navigation()]
    });
    
    var layer = new OpenLayers.Layer.Vector('test', {
      isBaseLayer: true
    });
    map.addLayer(layer);
    
    var feature1 = new OpenLayers.Feature.Vector(buffer, null, { fillColor: 'blue'});
    layer.addFeatures([feature1]);
    var feature2 = new OpenLayers.Feature.Vector(input, null, { fillColor: 'red'});
    layer.addFeatures([feature2]);
    
    map.zoomToMaxExtent();
    
  }
</script>
</head>
<body onload="init()">
	Input geometry is buffered by 20 units (input is red result is blue). 
	<div id="map" style="width:500px;height=500px;"></div>
</body>
</html>