docs: def gnomonicImageToSphere(x, y):
      """
      Inverse gnomonic projection (deg).
      """
      # Convert angle to [-180, 180] interval
      x = x - 360.*(x>180)
      x = np.asarray(x)
      y = np.asarray(y)
      lon = np.degrees(np.arctan2(y, x))
      r_theta = np.sqrt(x**2 + y**2)
      lat = np.degrees(np.arctan(180. / (np.pi * r_theta)))
      return lon, lat