code: def _get_affine_transform(self):
          
          # How big is the projected globe?
          # In the case of a stereonet, it's actually constant.
          xscale = yscale = self._scale
          # Create an affine transform to stretch the projection from 0-1
          return Affine2D() \
              .rotate(np.radians(self.rotation)) \
              .scale(0.5 / xscale, 0.5 / yscale) \
              .translate(0.5, 0.5)
docs: The affine portion of the base transform. This is called by
          LambertAxes._set_lim_and_transforms.