--- step-12/index.html	2016-09-17 21:44:04.000000000 +0200
+++ step-13/index.html	2016-09-17 21:44:04.000000000 +0200
@@ -1,6 +1,6 @@
 <html>
   <head>
-    <title>Step 12: geometry layer</title>
+    <title>Step 13: geometry from external source</title>
     <script src="../OpenLayers.js"></script>
     <script src="../OpenStreetMap.js"></script>
     <script src="http://maps.google.com/maps/api/js?sensor=false"></script>
@@ -35,7 +35,7 @@
       function init() {
         lat       = 52.025;
         lon       = 8.515;
-        zoom      = 15;
+        zoom      = 14;
 
         projLonLat   = new OpenLayers.Projection("EPSG:4326");   // WGS 1984
         projMercator = new OpenLayers.Projection("EPSG:900913"); // Spherical Mercator
@@ -71,18 +71,17 @@
         map.setCenter(new OpenLayers.LonLat(lon, lat).transform(projLonLat,projMercator), zoom);
         overviewMap.maximizeControl();
 
-        var layerGeometry = new OpenLayers.Layer.Vector("Gebiete",{projection: projMercator});
+        var layerGeometry = 
+            new OpenLayers.Layer.Vector("Gebiete", {
+                    strategies: [new OpenLayers.Strategy.Fixed()],
+                    protocol: new OpenLayers.Protocol.HTTP({
+                        url: "geom.json",   
+                        format: new OpenLayers.Format.GeoJSON()
+                    }),
+                    projection: projMercator
+            });
         map.addLayer(layerGeometry);
 
-        var json_data = '{"type":"Polygon","coordinates":[[[946997.668901750002988,6804851.635990919545293],[947398.27435326797422,6805510.242152039892972],[947937.327855485025793,6806519.116099460050464],[947876.502885716035962,6806705.792200200259686],[948839.171578197972849,6807214.812279700301588],[948866.945791151025333,6806943.305583120323718],[948825.81323930202052,6806740.500387510284781],[948825.679655913030729,6806649.948161319829524],[948920.913480286952108,6806218.210386379621923],[949167.475020444951952,6805973.516733709722757],[949428.474698559031822,6805492.619279350154102],[949490.268147898023017,6805254.51523463986814],[949368.818583442945965,6804879.135642670094967],[949300.679923127987422,6804730.331076799891889],[949117.704076112015173,6804232.10446386039257],[948833.071270102052949,6803457.073904880322516],[948178.668511525029317,6803987.724127359688282],[947673.177835781942122,6804222.643158700317144],[946997.668901750002988,6804851.635990919545293]]]}';
-
-        var geojson_format = new OpenLayers.Format.GeoJSON();
-        var geometry = geojson_format.read(json_data, 'Geometry');
-        var vector = new OpenLayers.Feature.Vector(geometry);
-        layerGeometry.addFeatures(vector);
-
-        map.zoomToExtent(layerGeometry.getDataExtent());
-
         markers = new OpenLayers.Layer.Markers("Markers");
         map.addLayer(markers);
 
@@ -110,6 +109,8 @@
         };
         marker.events.register("mousedown", feature, markerClick);
         markers.addMarker(marker);
+
+        map.setCenter(new OpenLayers.LonLat(lon, lat).transform(projLonLat,projMercator), zoom);
 }
     </script>
   </head>