Remove all objects from GTFS data that are not used in all relations that they are required to be. That is, agency-routes relation (agency_id), routes-trips relation (route_id), trips-shapes relation (shape_id), trips-frequencies relation (trip_id), trips-stop_times relation (trip_id), stop_times-stops relation (stop_id), and trips-calendar relation (service_id), recursively, until GTFS data does not reduce its size anymore. For example, if one agency_id belongs to routes but not to agency will be removed. This might cause one cascade removal of objects in other relations that originally did not have any inconsistency.
Arguments
- gtfs_data
A list of data.tables read using gtfs2gps::reag_gtfs().
- only_essential
Remove only the essential files? The essential files are all but agency, calendar, and routes. Default is TRUE, which means that agency-routes, routes-trips, and trips-calendar relations will not be processed as restrictions to remove objects.
- prompt_invalid
Show the invalid objects. Default is FALSE.
Examples
poa <- read_gtfs(system.file("extdata/poa.zip", package = "gtfs2gps"))
#> Unzipped the following files to /tmp/RtmpVbDcru/gtfsio:
#> * agency.txt
#> * calendar.txt
#> * routes.txt
#> * shapes.txt
#> * stop_times.txt
#> * stops.txt
#> * trips.txt
#> Reading agency
#> Reading calendar
#> Reading routes
#> Reading shapes
#> Reading stop_times
#> Reading stops
#> Reading trips
object.size(poa)
#> 1173232 bytes
subset <- remove_invalid(poa)
object.size(subset)
#> 1173232 bytes