docs: def gnomonicSphereToImage(lon, lat):
      """
      Gnomonic projection (deg).
      """
      # Convert angle to [-180, 180] interval
      lon = lon - 360.*(lon>180)
      lon = np.radians(lon)
      lat = np.radians(lat)
      r_theta = (180. / np.pi) / np.tan(lat)
      x = r_theta * np.cos(lon)
      y = r_theta * np.sin(lon)
      return x, y