New challenges with De Lijn GTFS data for July 2024
by multimob — written on 2024-06-20
Every 6 months now, De Lijn applies a bunch of changes, namely new stops, new lines or line renumbering.
We are entering a blurry period where GTFS data feeds show the old and new network in the same dataset. The list of routes is now very long (1,521 rows in the table).
In theory that should not be a real problem because the calendar can easily identify the routes that will no longer operate after June 30, and those that start their operations on July 1.
We have a small routine that can filter out timetables before a given date and generate proper route_ref:De_Lijn values of the new situation. We will use this when uploading changes.
But datasets are full of surprises, again.
Many routes are duplicated, even new routes. There is a new bus 86 operating between Boom and Mechelen, and it was split into two identical lines in GTFS, each with about half of the trips. So, if you are in Boom Vrijheidstraat, one line in GTFS tells you bus 86 to Mechelen departs at 5:52, 6:52, 7:07, 7:37… and another line says bus 86 to Mechelen departs at 6:22, 7:22, 7:52… and this is in fact the same service.
De Lijn’s website also mentions that a new route 868 between Boom and Tisselt will start operating on July 1, to replace route 258. GTFS data for route 258 correctly gives timetables up to June 30 and nothing after that date. But that same GTFS dataset makes no mention at all of the new route 868! No mention either of the new route 869 and possibly more. We are confident that they will fix their source data in the next days—after all, it is still 10 days before the change—but for the moment it is not possible to automate the network changes, the amount of human review is huge.
Finally, most school lines (numbered in the 500-599 range) do not operate in July and August. Having no single trip on those routes make it impossible to properly assign stops to those routes and calculate route_ref:De_Lijn tags reliably. We must resolve to abstain from automatically update those tags until September if we want to avoid mistakes.
Permalink: https://blog.multimob.be/zzighooh8a.htm