Join the shapes, trips and routes tables together - also checks on some potential errors in the data and warns accordingly
shape_route_service(gtfs_obj, route_ids = NULL, service_ids = NULL)
a gtfs object
the routes for which to join the tables together - required, but not sure why this can't just be any/all routes in routes_df
an optional filter for a certain service-default NULL
shapes_routes_service - a dataframe in which routes, services, and shape_ids are all joined