this.baseLayer.setVisibility(false, noEvent); 
this.baseLayer.setVisibility(false); 
    setBaseLayer: function(newBaseLayer, noEvent) {        var oldExtent = null;        if(this.baseLayer) {            oldExtent = this.baseLayer.getExtent();        }        if (newBaseLayer != this.baseLayer) {                      // is newBaseLayer an already loaded layer?m            if (OpenLayers.Util.indexOf(this.layers, newBaseLayer) != -1) {                // make the old base layer invisible                 if (this.baseLayer != null) {                    this.baseLayer.setVisibility(false, noEvent);                }                // set new baselayer and make it visible                this.baseLayer = newBaseLayer;                                // Increment viewRequestID since the baseLayer is                 // changing. This is used by tiles to check if they should                 // draw themselves.                this.viewRequestID++;                this.baseLayer.visibility = true;                //redraw all layers                var center = this.getCenter();                if (center != null) {                    if (oldExtent == null) {                        // simply set center but force zoom change                        this.setCenter(center, this.getZoom(), false, true);                    } else {                        // zoom to oldExtent *and* force zoom change                        this.setCenter(oldExtent.getCenterLonLat(),                                        this.getZoomForExtent(oldExtent),                                       false, true);                    }                }                if ((noEvent == null) || (noEvent == false)) {                    this.events.triggerEvent("changebaselayer");                }            }                }    },
2032	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/2032/0e8e7ab620ec81e0909f04e0a03025090b347ff8/Map.js/clean/lib/OpenLayers/Map.js