class_docstr: General object for handling the scale of the geometries used in a Feature.
docstr: Given an extent, update the scale.
  
  Parameters
  ----------
  extent
      The boundaries of the plotted area of a projection. The
      coordinate system of the extent should be constant, and at the
      same scale as the scales argument in the constructor.
docstr_tok: ["Given","an","extent",",","update","the","scale",".","Parameters","--","--","--","--","--","extent","The","boundaries","of","the","plotted","area","of","a","projection",".","The","coordinate","system","of","the","extent","should","be","constant",",","and","at","the","same","scale","as","the","scales","argument","in","the","constructor","."]
code: def scale_from_extent(self, extent):
      """
      Given an extent, update the scale.
  
      Parameters
      ----------
      extent
          The boundaries of the plotted area of a projection. The
          coordinate system of the extent should be constant, and at the
          same scale as the scales argument in the constructor.
  
      """
      # Note: Implementation does nothing. For subclasses to specialise.
      return self._scale
  
imports: from abc import ABCMeta, abstractmethod
  import numpy
  import shapely.geometry
  import cartopy.crs
  import cartopy.io.shapereader
label_desc: Use image node_id 3 for calling the Scaler obj's underlying member method code with example usage: obj.scale_from_extent(extent) and returns: self