Improved docs for GEOSGeometry.simplify()

.. method:: GEOSGeometry.simplify(tolerance=0.0, preserve_topology=False)

Returns a new :class:`GEOSGeometry`, simplified using the Douglas-Peucker

algorithm to the specified tolerance.  A higher tolerance value implies

less points in the output.  If no tolerance is tolerance provided,

it defaults to 0.

By default, this function does not preserve topology - e.g.,

:class:`Polygon` objects can be split, collapsed into lines or disappear.

:class:`Polygon` holes can be created or disappear, and lines can cross.

Returns a new :class:`GEOSGeometry`, simplified to the specified tolerance

using the Douglas-Peucker algorithm. A higher tolerance value implies

fewer points in the output. If no tolerance is provided, it defaults to 0.

By default, this function does not preserve topology. For example,

:class:`Polygon` objects can be split, be collapsed into lines, or disappear.

:class:`Polygon` holes can be created or disappear, and lines may cross.

By specifying ``preserve_topology=True``, the result will have the same

dimension and number of components as the input, however, this is

significantly slower.

dimension and number of components as the input; this is significantly

slower, however.

.. method:: GEOSGeometry.sym_difference(other)