code: def geodetic2authalic(
      geodetic_lat, ell: Ellipsoid = None, deg: bool = True
  ):
      """
      converts from geodetic latitude to authalic latitude
  
      like Matlab map.geodesy.AuthalicLatitudeConverter.forward()
  
      Parameters
      ----------
      geodetic_lat : float
           geodetic latitude
      ell : Ellipsoid, optional
           reference ellipsoid (default WGS84)
      deg : bool, optional
           degrees input/output  (False: radians in/out)
  
      Returns
      -------
      authalic_lat : float
           authalic latiude
  
      Notes
      -----
      Equations from J. P. Snyder, "Map Projections - A Working Manual",
      US Geological Survey Professional Paper 1395, US Government Printing
      Office, Washington, DC, 1987, pp. 13-18.
  
      """
      geodetic_lat, ell = sanitize(geodetic_lat, ell, deg)
  
      e = ell.eccentricity
      f1 = e**2 / 3 + 31 * e**4 / 180 + 59 * e**6 / 560
      f2 = 17 * e**4 / 360 + 61 * e**6 / 1260
      f3 = 383 * e**6 / 45360
  
      authalic_lat = (
          geodetic_lat
          - f1 * sin(2 * geodetic_lat)
          + f2 * sin(4 * geodetic_lat)
          - f3 * sin(6 * geodetic_lat)
      )
  
      return degrees(authalic_lat) if deg else authalic_lat
  
imports: from __future__ import annotations
  import warnings
  from math import pi
  from .None import rcurve
  from .ellipsoid import Ellipsoid
  from .mathfun import asinh, atan, atanh, cos, degrees, exp, inf, radians, sign, sin, sqrt, tan
  from .utils import sanitize
label_desc: Use image node_id 10 for calling a global function with example usage: geodetic2authalic(geodetic_lat, ell, deg) and returns: unknown