'Save information required to reproduce the current view.
Called before a view is changed, such as during a pan or zoom
initiated by the user. You may return any information you deem
necessary to describe the view.
.. note::
Intended to be overridden by new projection types, but if not, the
default implementation saves the view limits. You *must* implement
:meth:`_set_view` if you implement this method.'

def _get_view(self):

    (xmin, xmax) = self.get_xlim()
    (ymin, ymax) = self.get_ylim()
    return (xmin, xmax, ymin, ymax)
