code: function(resolution, closest) {
          var zoom = null;
          if (this.baseLayer != null) {
              zoom = this.baseLayer.getZoomForResolution(resolution, closest);
          }
          return zoom;
      }
docs: APIMethod: getZoomForResolution
  
  Parameters:
  resolution - {Float}
  closest - {Boolean} Find the zoom level that corresponds to the absolute
  closest resolution, which may result in a zoom whose corresponding
  resolution is actually smaller than we would have desired (if this
  is being called from a getZoomForExtent() call, then this means that
  the returned zoom index might not actually contain the entire
  extent specified... but it'll be close).
  Default is false.
  
  Returns:
  {Integer} A suitable zoom level for the specified resolution.
  If no baselayer is set, returns null.