OpenLayers with sphericalMercator and WFS
Me and my team mates at the university today spent hours on trying to get Vectors from a Web Feature Service correctly placed on a Google Maps Layer in OpenLayers. So here is a description how you can make it work.

Google Maps uses another system of geocoordinates, so a projection is needed. Your map should be created with these options:
var options = {
projection: new OpenLayers.Projection("EPSG:900913"),
displayProjection: new OpenLayers.Projection("EPSG:4326"),
units: "m",
numZoomLevels: 18,
maxResolution: 156543.0339,
maxExtent: new OpenLayers.Bounds(-20037508, -20037508,
20037508, 20037508.34)
};
map = new OpenLayers.Map('map', options);

Your layer needs special handling, too (sphericalMercator):
var gmap = new OpenLayers.Layer.Google("Google", {"sphericalMercator": true});
map.addLayers([gmap]);

Also the results from the WFS need to run through the projection. Call it similar to this:
var layer = new OpenLayers.Layer.WFS( "Krankenhaus",
"http://chrifhost.webhop.org:8080/WFS_Server/WFS/",
{typename: "HOSPITAL", maxfeatures: 1000},
{projection: new OpenLayers.Projection("EPSG:4326"),
extractAttributes: true});
map.addLayers([layer]);

Your points are already placed correctly now. If you want to set the center of the map to some specific area that you have in lat/lng coordinates, they need to be changed to match the new system used by the map. An example for Germany:
map.setCenter(OpenLayers.Layer.SphericalMercator.forwardMercator(10.455278, 51.165), 2);
andre wisplinghoff | 11. Juli 09 | Topic OpenLayers | 0 Kommentare  | Kommentieren