Keep a Google Maps v3 Map hidden, show when needed

Or you could just hide it like with css visablility or css opacity.

$("#GoogleMap").css({ opacity: 0, zoom: 0 });
initialize();

google.maps.event.addListener(map,"idle", function(){ 
     $('#Loader').hide();
     $("#GoogleMap").css({ opacity: 1, zoom: 1 });
}); 

Also remember to call:

google.maps.event.trigger(map, 'resize');

if you have changed the size of the <div>. A display:none <div> has no size.