[OpenLayers-Users] displacement of google satellite data compared to google streetmap

[Joanne Cook]

Hi List,

I have a map that I thought was all correctly set up to use spherical mercator, and all my data (which is all projected in 900913) is correctly displaying on either open streetmap or google streets data. However, when I add a google satellite or hybrid layer, the initial load of the map shows the satellite layer displaced several hundred miles to the west. If I switch to the google streets layer without any zooming or panning, the displacement disappears. If I then switch back to the google satellite layer, again with no zooming or panning, it appears in the correct place. Throughout all of this, my data layer has no displacement. Furthermore, since all of this is set within mapfish, with extjs used for side panels, if I minimise the side panel while the displacement is occurring it also removes the displacement. I'm using the svn versions of openlayers and mapfish.

This is the code relating to setting up the map and layers:

function createMap() {
	var options = {
		projection: new OpenLayers.Projection("EPSG:900913"),
        displayProjection: new OpenLayers.Projection("EPSG:27700"),
        units: "m",
        maxResolution: 156543.0339,
        maxExtent: new OpenLayers.Bounds(-20037508.34, -20037508.34,
                                                 20037508.34, 20037508.34)
	};
return new OpenLayers.Map('olmap',options);
} //end createmap

function addlayers(map){
	
	
	// define wms
	layer = new OpenLayers.Layer.WMS("OA Sites WMS", "http://geoserver.thehumanjourney.net:80/geoserver/wms?",
                           {layers: 'oadigi:oasites', transparent: true, format: 'image/png', buffer:0},
                            {isBaseLayer: false});
	
	
	
	// create Google Mercator layers
            var gmap = new OpenLayers.Layer.Google(
                "Google Streets",
                {'sphericalMercator': true}
            );
            var gsat = new OpenLayers.Layer.Google(
                "Google Satellite",
                {type: G_SATELLITE_MAP, 'sphericalMercator': true, numZoomLevels: 22}
            );
            var ghyb = new OpenLayers.Layer.Google(
                "Google Hybrid",
                {type: G_HYBRID_MAP, 'sphericalMercator': true}
            );

    	
	// define pseudo-layer for highlighting selected features
	select = new OpenLayers.Layer.Vector("Selection", 
		{protocol: new mapfish.Protocol.TriggerEventDecorator(protocol),
		strategies: [new mapfish.Strategy.ProtocolListener({append: true})],
		styleMap: new OpenLayers.Style(OpenLayers.Feature.Vector.style["select"]), 
		displayInLayerSwitcher: false});
		
    
	// add layers
	map.addLayers([layer, select, gmap, gsat, ghyb]);

} //end addlayers

function setMapCenter() {
//define a new projection object so map can be centred using latlong
	var proj = new OpenLayers.Projection("EPSG:4326");
	var point = new OpenLayers.LonLat(-2.9, 53.6);
	this.setCenter(point.transform(proj, this.getProjectionObject()), 6);
} //end setMapCenter

I hope that's enough information for someone as it's hard for me to get this map accessible to the outside world yet.

Many thanks

Jo

-- 
-----------------------------------------------------
Joanne Cook
Senior IT Support and Development
Oxford Archaeology (North)
01524 880212
http://thehumanjourney.net


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