Add GTFS-RT feeds for Paris, France (IDFM network, feeds provided)

[kalon33]

Thanks to https://github.com/Jouca/IDFM_GTFS-RT, GTFS-RT feeds are now available for IDFM network in Paris, France generated from static GTFS, and PRIM real-time data APIs provided by Ile de France Mobilités (IDFM).

It would be a great addition to add http://gtfsidfm.clarifygdps.com/gtfs-rt-trips-idfm (Trips Updates) and http://gtfsidfm.clarifygdps.com/gtfs-rt-alerts-idfm (Alerts) GTFS-RT feeds to the data available in Transitous.

Thanks for your help :)

[pialwis]

https://github.com/Jouca/IDFM_GTFS-RT is an unofficial Java web app not maintained by IDFM. Looking at the code, this web app fetches different IDFM resources in order to generate GTFS-RT feeds. The fetched resources are:

• https://data.iledefrance-mobilites.fr/explore/dataset/offre-horaires-tc-gtfs-idfm/files/a925e164271e4bca93433756d6a340d1/download/, the GTFS feed (note that the link is different from the one Transitous uses, which is the link from the French government and not IDFM. I don't think that matters that much).
• https://prim.iledefrance-mobilites.fr/marketplace/disruptions_bulk/disruptions/v2 for all realtime alerts in SIRI-Lite JSON format (official doc here, API key needed).
• https://prim.iledefrance-mobilites.fr/marketplace/estimated-timetable?LineRef=ALL for all realtime next departure data in SIRI-Lite JSON format (official doc here, API key needed).

IDFM does not provide (and in my opinion will never provide) GTFS-RT feeds despite them providing a GTFS feed, hence the existence of the IDFM_GTFS-RT project.

Motis has experimental support for SIRI-Lite and very recently NeTEx. IDFM also provides a NeTEx feed here: https://prim.iledefrance-mobilites.fr/marketplace/iboo/netex.zip (official doc here, API key needed). Instead of using an unofficial GTFS-RT bridge, it might be better to directly use the official feeds and let Motis do the realtime math?

I am mentioning NeTEx because a couple weeks ago I try deploying a local Motis server that uses both the IDFM GTFS and SIRI (json) feeds, but realtime data did not work because IDFM uses different stop and trip ids for these two feeds. From what I've seen, https://github.com/Jouca/IDFM_GTFS-RT is changing the ids from SIRI-Lite feeds so that they match the ones of the GTFS feed (see here for example). Maybe using NeTEx instead of GTFS in Motis will fix the id issue, but I did not have time to test that yet.

Btw, the two GTFS-RT links you provided do not support TLS. That's a shame.

[felixguendling]

I think adding trip updates and alerts from the sources @kalon33 mentions is probably the fastest way to get something working. So it could be an option to add those sources now and switch to something NeTEx+SIRI based later. At the moment, the deployed version does not support NeTEx+SIRI (it's released but not deployed for Transitous).

uses different stop and trip ids for these two feeds

MOTIS currently does not use trip IDs because they don't match very well in most feeds anyway. The matching is done using stop IDs and scheduled trip times. Matching on partial trip segments works. If a RT feed uses other stop IDs than the ones in the static feed but the RT feed stop IDs are known with their geo coordinates (from other sources), these stops can be added to stops.txt and MOTIS will associate them with the "real" stop IDs (based on geo-coordinates) which enables real-time matching.

[traines-source]

There is already an open PR for that #1699, just that we first need to slightly rework the way the french script works #1701. Sorry, I and apparently no one else has come around to that yet.

@pialwis Correct me if I'm wrong, but there is no SIRI ET feed, just departure timetables or something like that. So as @felixguendling says it's probably easiest and best to take the feed that @Jouca prepared.

[pialwis]

Ok thanks for your answers!

@traines-source yes from what I've seen IDFM only provides realtime stop timetables and realtime alerts (here and here), that is SIRI-SM and SIRI-SX. I did not see any API to retrieve realtime data for a route. There is a SIRI ET API endpoint (here) but you can only fetch data for a single route at a time.

[jbruechert]

The rework of the script to update the list of sources in France is now done, so you can now just add the new source as with any other country.

[kalon33]

@jbruechert Thanks for your work ! Something like #1796 ?

[kalon33]

Fixed by #1796.