A review of the existing data in 5 most populated cities of France was detailed in our previous diary. Through this diary, we will be introducing you all to a handy tool for mapping turn restrictions.

Adding turn restrictions using OSM Navigation Map

OSM navigation map is an open tool that was built to review and add missing data for turn restrictions. It relies on Mapillary as a source to identify the turn restrictions in the detected traffic signages from the street level images captured by the volunteers.

The data team in Mapbox has used this tool for reviewing the existing restrictions and as well adding the missing ones for US cities, 5 cities each in Canada and Germany. The tool assists in reviewing the restrictions easily and quickly.

detected_only_right_turn Detected signage of only_right_turn restriction in Mapillary

detected_no_right_turn_france Detected signage of no_right_turn restriction in Mapillary

screen shot 2016-09-19 at 12 18 03 pm Verifying turn restriction with images from Mapillary in OSM Navigation Map

screen shot 2016-09-19 at 12 41 39 pm Reviewing turn restriction in OSM Navigation Map

Explore the tool with a detailed guide on GitHub on how to use the tool for reviewing and adding missing turn restrictions on OpenStreetMap.

Community participation has already ensured that around 436 turn restrictions across 5 cities (Paris, Marseille, Lyon, Toulouse, and Nice) of France :clap: :tada: . Along with the local knowledge, this tool would be a great companion to improve data in OpenStreetMap for navigation.

If it’s your first time mapping turn restrictions, read the guide on mapping turn restrictions using Mapillary to understand different scenarios and special cases. Help us by updating the special cases list for France that would help all community mappers as well our mapping team to be aware of these cases while reviewing turn restrictions.

We would love to collaborate with the community on improving the data in OpenStreetMap by collectively getting feedback on our tools as well as workflow.

As most of us in the team are English speakers, it is difficult for us to translate the guide into French. It would be great if the community members can help us in translating the OSM Navigation Map guide to French and host it on OpenStreetMap wiki or anywhere that would be valuable for local mappers to refer.


Comment from escada on 21 September 2016 at 05:46

As for the first picture, it’s a complex case. It depends on a number of things

1) whether the “from” street is split in 2 just before the crossing. The only_right turn sign is only for the right lane. 2) is the left-right street drawn as 1 OSM way or 2 with oneway = yes on it ? 3) is the street on the other side of the crossing oneway or not ?

So perhaps you need a “no_straight_ahead” or a “only_left” for the left way…

Comment from BharataHS on 26 September 2016 at 09:11

Thank you @escada for clarifying the special case for the restriction.

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