OSM Hack Weekends October and November 2025

Saturday, 15 November 2025  |  Volker Krause

Last weekend I once again attended the bi-annual OSM Hack Weekend in Karlsruhe hosted by Geofabrik. I’ve also been at the OSM Hack Weekend in Berlin hosted at Wikimedia Deutschland a couple of weeks ago and haven’t written about that yet, so this is the combined report for both events.

Transitous

Transitous, our community-run public transport routing service, has been the topic of several discussions:

  • Ways to deal with GTFS static feed rotation happening out of sync with corresponding realtime feeds. This results in time periods where available realtime information cannot be matched to base schedule data and thus gets needlessly discarded.
  • How to best configure GBFS provider groups as supported by MOTIS v2.7.
  • Integrating GBFS data from Citybikes, which would substantially increase the amount of available rental vehicle data.
  • Assessing what it would take to add Transitous as an additional routing option to the OpenStreetMap website.
  • Investigating how far along the OSM Road Closures GSoC project is, as that kind of data is obviously very interesting to integrate eventually.
  • Exploring whether FOSSGIS e.V. would be a suitable organisational home for Transitous.
Map view with icons indicating available station based as well as free-floating bikes/cars, and a provider group selector in the lower right.
Available rental vehicles shown on Transitous' map view.

KPublicTransport

KPublicTransport, KDE’s client library for accessing different journey planning services used by Itinerary and KTrip, got a few improvements to catch up with Transitous and MOTIS v2.6 and v2.7 changes:

  • Access to agency/operator URLs.
  • Querying available station-bound and free-floating rental vehicles from MOTIS.
  • Support for direct booking URLs for station-based rental vehicles.

Station-bound rental vehicles other than bikes are now also displayed with the correct vehicle icon on the map.

Small part of a map with green bike and car rental icons, the car one showing how many vehicles are available at this station.
Itinerary's station map showing a car rental station and two free-floating rental bikes.

Indoor mapping

Indoor mapping was of course also on the agenda:

  • I got to try Tobias’s JOSM patches improving level filtering. Especially the option to filter on elements without a level tag is helpful for fixing level tagging in existing buildings for me.
  • We talked about ongoing tagging discussions from TU Munich’s BIM import, in preparation for the next quarterly OSM Indoor Meetup.
  • We discussed whether we should have another in-person Indoor tagging workshop following the one from 2022, in order to have some time to work on finalizing tagging proposals and updating the current indoor tagging documentation.

Emergency and weather alerts

At the CAP Implementation Workshop two weeks ago a WFS/OGC feature layer for CAP alerts was mentioned, and presented as something so far only offered by a commercial entity.

With my almost non-existent GIS knowledge this looked like something that shouldn’t be too hard to provide by our CAP alert aggregation service as well. And thanks to the input from the right people I got a basic prototype set up in less than an hour. All the magic is provided by pg_featureserv, which can expose a PostGIS database (which we already have) in a way it can be consumed by e.g. QGIS.

QGIS showing CAP alert message areas from an OGC layer taken from a local FOSS Public Alert Server instance on top of an OSM base map.
QGIS with a CAP alert message layer.

One important difference here is that unlike its proprietary counter-part this doesn’t expose many CAP fields yet, as we hold only the bare minimum as dedicated database columns right now. However, should anyone actually need this, adding more columns isn’t a big deal.

Event planning

We also looked at upcoming events in 2026 and how we could have Transitous specifically and the Open Transport community more generally represented there:

  • 39C3, 27-30 Dec in Hamburg Germany. We’ll try to have some kind of Transitous meetup there.
  • FOSDEM, 31 Jan-1 Feb in Brussels, Belgium. The CfP for the Railways & Open Transport track is still open and we have poked a few people to submit talks.
  • FOSSGIS-Konferenz, 25-28 Mar in Göttingen, Germany. The CfP is already closed, a few proposals have been submitted.

Still further out is next year’s State of the Map which will be end of August in Paris, France. That’s obviously something where Transitous should be present as well, and where we might have the option of a travel-optimized adjacent Transitous sprint along the way.

Ideas for a 2026 edition of the Open Transport Community Conference are also floating around already, volunteers to drive this still very much needed though.

You can help!

Hack weekends how this is called in the OSM community or sprints as this is known in the KDE community are immensely valuable and productive. There’s a great deal of knowledge transfer happening, and they are a big motivational boost.

However, physical meetings incur costs, and that’s where your donations help! KDE e.V. and local OSM chapters like the FOSSGIS e.V. support these activities.