diff --git a/lib/OpenLayers/Map.js b/lib/OpenLayers/Map.js
index 3b12280895..39de0da4ea 100644
--- a/lib/OpenLayers/Map.js
+++ b/lib/OpenLayers/Map.js
@@ -350,15 +350,16 @@ OpenLayers.Map.prototype = {
      * @param {Boolean} noEvent
      */
     setBaseLayer: function(newBaseLayer, noEvent) {
+        var oldBaseLayer = this.baseLayer;
 
-        if (newBaseLayer != this.baseLayer) {
+        if (newBaseLayer != oldBaseLayer) {
           
             // is newBaseLayer an already loaded layer?
             if (this.layers.indexOf(newBaseLayer) != -1) {
 
                 // make the old base layer invisible 
-                if (this.baseLayer != null) {
-                    this.baseLayer.setVisibility(false, noEvent);
+                if (oldBaseLayer != null) {
+                    oldBaseLayer.setVisibility(false, noEvent);
                 }
 
                 // set new baselayer and make it visible
@@ -368,13 +369,9 @@ OpenLayers.Map.prototype = {
                 //redraw all layers
                 var center = this.getCenter();
                 if (center != null) {
-                    var zoom = this.getZoom();
-                    this.zoom = null;
-                    if (zoom > this.baseLayer.numZoomLevels - 1) {
-                        zoom = this.baseLayer.numZoomLevels - 1;
-                    }    
+                    var oldResolution = oldBaseLayer.getResolution();
+                    var zoom = this.baseLayer.getZoomForResolution(oldResolution);
                     this.setCenter(center, zoom);            
-                
                 }
                 if ((noEvent == null) || (noEvent == false)) {
                     this.events.triggerEvent("changebaselayer");