class_docstr: Base class for formatting ticks on geographical axes using a
  rectangular projection (e.g. Plate Carree, Mercator).
class_docstr_tok: ["Base","class","for","formatting","ticks","on","geographical","axes","using","a","rectangular","projection","(","e.g",".","Plate","Carree",",","Mercator",")","."]
docstr: Given both a tick value in the Plate Carree projection and the
  same value in the source CRS, return a string indicating the
  hemisphere that the value is in.
  
  Must be over-ridden by the derived class.
code: def _hemisphere(self, value, value_source_crs):
      """
      Given both a tick value in the Plate Carree projection and the
      same value in the source CRS, return a string indicating the
      hemisphere that the value is in.
  
      Must be over-ridden by the derived class.
  
      """
      raise NotImplementedError(
          "A subclass must implement this method."
      )
  
imports: import matplotlib
  from matplotlib.ticker import Formatter, MaxNLocator
  import numpy
  import cartopy.crs
  from cartopy.mpl.geoaxes import GeoAxes
label_desc: Use image node_id 11 for calling the _PlateCarreeFormatter obj's underlying member method code with example usage: obj._hemisphere(value, value_source_crs) without return types