code: def zoom_level
        region = self.region
        center_pixel = region.center.to_pixel_space
        top_left_pixel = (region.center - (region.span / 2)).to_pixel_space
  
        scaled_map_width = (center_pixel.x - top_left_pixel.x) * 2
        map_size_in_pixels = MapSize.new(self.bounds.size)
  
        zoom_scale = scaled_map_width / map_size_in_pixels.width
        zoom_exponent = log(zoom_scale) / log(2)
        20 - zoom_exponent
      end
docs: Get the current zoom level
  
   * *Returns* :
     - Zoom level as a Float