code: def projected_area_factor(ax, original_crs):
      
      if not hasattr(ax, 'projection'):
          return 1
      if isinstance(ax.projection, ccrs.PlateCarree):
          return 1
      x1, x2, y1, y2 = ax.get_extent()
      pbounds = \
          get_projection_from_crs(original_crs).transform_points(ax.projection,
                      np.array([x1, x2]), np.array([y1, y2]))
  
      return np.sqrt(abs((x2 - x1) * (y2 - y1))
                     /abs((pbounds[0] - pbounds[1])[:2].prod()))
docs: Helper function to get the area scale of the current projection in
      reference to the default projection.