Fixing incorrect highway junctions in Belgium

Hi everyone,

(I’m including a French and Dutch version of this message below.)

My team at TomTom is continuing to look into issues in the map that we can correct to help improve the road network quality in Belgium. While we carry on fixing incorrect intersections between buildings and highways, we have now also identified some situations in which highway junctions may be incorrectly or imprecisely mapped. Fixing these cases helps improve the navigation experience in routing applications relying on OSM data.

To allow our editing team to assess and, where needed, correct these situations, we’ve created a MapRoulette challenge: “Fix Incorrect Highway Junctions”. It contains a task for each case we identified—97 in total.

Our editors may pick up this challenge in a couple of weeks or so. As always, it is public, so anyone who’s interested can take a look at the potential issues we detected.

If you have any questions or comments, just shout.

Have a great day!



Bonjour à tous,

Mon équipe chez TomTom travaille sur l’amélioration de la qualité du réseau routier en Belgique en examinant les anomalies de la carte que nous pouvons résoudre. Alors que nous continuons à corriger les intersections incorrectes entre les bâtiments et les routes, nous avons également identifié des situations dans lesquelles les jonctions routières peuvent être cartographiées de manière incorrecte ou imprécise. La correction de ces cas permet d’améliorer l’expérience de navigation dans les applications de routage qui s’appuient sur les données OSM.

Pour permettre à notre équipe d’éditeurs d’évaluer et, le cas échéant, de corriger ces situations, nous avons créé un défi MapRoulette : “Fix Incorrect Highway Junctions”. Il contient une tâche pour chaque cas que nous avons identifié—97 au total.

Nos éditeurs pourraient se pencher sur ce défi d’ici quelques semaines. Comme toujours, il est public, de sorte que toute personne intéressée puisse jeter un coup d’œil aux cas détectés.

Si vous avez des questions ou des commentaires, n’hésitez pas à m’en faire part.

Je vous souhaite une excellente journée !



Hey iedereen

Ons team bij TomTom blijft uitkijken naar fouten in OSM die we kunnen corrigeren om de kwaliteit van het wegennetwerk in België verder te verbeteren. Terwijl we verdergaan met het fixen van incorrecte kruisingen tussen gebouwen en wegen, hebben we nu ook een aantal situaties gevonden waarin wegenknooppunten mogelijk onjuist of onnauwkeurig in kaart gebracht zijn. Deze fouten corrigeren zorgt voor een betere navigatie-ervaring in routingtoepassingen gebaseerd op OSM-data.

Om onze editors in staat te stellen deze situaties na te kijken en te verbeteren waar nodig, hebben we een MapRoulette-challenge aangemaakt: “Fix Incorrect Highway Junctions”. Deze challenge bevat een taak voor elke mogelijk incorrecte situatie die we gevonden hebben—97 in totaal.

Ons team kan over een aantal weken met deze taken aan de slag gaan. Zoals altijd is de challenge openbaar, dus iedereen die geïnteresseerd is, kan de mogelijke fouten bekijken die we gedetecteerd hebben.

Geef maar een seintje als jullie vragen of opmerkingen hebben.

Fijne dag nog!



On building/highway intersections: this building turns up, but I think that’s correctly mapped Node: 5326140941 | OpenStreetMap
Second case: MapRoulette
Also a false positive I think

Thanks for taking a look Joost!

There’s always the possibility of false positives, which can be marked as “Not an issue”. Looking at the number of tasks fixed in that challenge so far vs. the number of tasks completed but not fixed, the validity of the tasks seems to meet expectations, but I will have my team look into the false positives you pointed out. If you see a pattern (the same type of false positive recurring), do let me know.

Apparently I’m the last modifier of the ways involved in this task, although all I did was add access=private and service=driveway to a bunch of service roads that were driveways. It looks to be wrongly mapped (assessing from aerial imagery here, would be difficult to survey since it’s a private driveway), however I’ve never used MapRoulette before and don’t really understand at this point how it works. Just letting you know since I’m the last modifier of these ways and didn’t notice the error here :grimacing:

Hi @queerthoughts,

No worries! If there is an issue (like I said before, in some cases there won’t be—there’s always the possibility of a false positive, which is why we’re manually checking these situations), that’s not necessarily on the last person who edited the elements at hand. And it’s okay to make mistakes or overlook other people’s mistakes–we all do :upside_down_face:.

This particular case was flagged as a potential error because the distance between the small driveway and the other way is so small. This indicates the mapping may have been incorrect or imprecise. I do agree it’s hard to tell from the aerial imagery here.

If you’re interested in trying out MapRoulette, here’s a quick intro to how it works:

  • You open one of the tasks, for instance
  • The instructions on the left will give you some pointers on how to complete the task.
  • Under “Completion”, choose your preferred editor from the “Current Editor” dropdown.
  • To properly assess and, if needed, correct the situation, click the “Edit” button.
  • Use the editor as you normally would and save your changes.
  • Go back to MapRoulette and select “I fixed it!” if you fixed the issue. If there is no actual issue, you can select “Not an Issue”. If the situation is too hard to assess from the imagery and information available, you can select “Can’t Complete”.

We use MapRoulette because it helps us spot false positives, so we can continuously improve the processes we use to identify issues in the data.
Note that in other countries where I’ve shared this type of challenge, I see that the amount of issues marked as actual issues ranged from ca. 85 to 95%, so I don’t expect a huge number of false positives.

If you have any questions, or comments about this challenge, don’t hesitate to let me know!


The highway junction challenge was completed within a day! Thanks everyone for your help :heart:

Coming back to these two cases in particular:

For the first one, in iD you’ll see that an issue pops up (“Delhaize crosses path” > “Highways crossing buildings should use bridges, tunnels, or different layers.”) because the shop and the path aren’t connected.

The second one is a false positive indeed.

Ah, thanks! I fixed that first one now.

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