def get_convex_hull_coordinates(gtfs):
lons, lats = _get_stop_lat_lons(gtfs)<EOL>lon_lats = list(zip(lons, lats))<EOL>polygon = MultiPoint(lon_lats).convex_hull<EOL>hull_lons, hull_lats= polygon.exterior.coords.xy<EOL>return hull_lats, hull_lons<EOL>
Parameters
----------
gtfs: gtfs.GTFS

Returns
-------
lons: list
    of floats
lats: list
    of floats