[Talk-gh] Unverifiable speed limits resulting from organised mapping in Accra

[Stephen Mawutor Donkor]

Thank you, Enock, for sharing the reference links; they will be valuable in
expanding on the ongoing investigation of the speed limit data collection
conducted in Accra by the TomTom Team.

I'd like to add that the TomTom Team didn't carry out this project
independently; they engaged closely with our community. The project
involved selected members of the YouthMappers community in Ghana, though
participation was limited to fewer than 20 trained individuals who
contributed to the mapping, for your information this campaign was excluded
of newbies; as you mentioned other wise. one needed to be an
intermediate or advance mapper to join the team.

Some issues have already been flagged, and Tomtom is/are exploring ways to
addressing them.

We’ve noticed instances where some participants didn’t refer to Mapillary
road sign data from our closing conversations, and in other cases, certain
speed limits recorded did not align with the reference standards we were
using.

While I feel that some feedback has been a bit harsh, I also believe we are
all here to learn from others and our own experiences. When mistakes
happen, it’s essential to focus on constructive solutions and use them as
learning curves/opportunities for all, not just be.
Make ref to:

[Ref_1] where some of the mappers shared ground truff data just to validate
their data

[Ref_4]the mappers were taught how to use mappillary data. sadly the data
doesn't cover much. We want as much as conducting a mappillary campaign but
you guess it is as good as mine.

[Ref_2] some strange speed limits on highways

[Ref_3] when mappers were unsure about what to do brough the conversation
back to the group.

once again, thank you for your continuous interest in the quality of data
coming  Ghana and in the OSM ecosystem, I would like to encourage you to
continually share your constructive feedback for the betterment of the
community and solutions to make some of these processes smoother.

thank you
Mawutor


ref_4:
https://drive.google.com/file/d/1Hmn7BiQnNuj-bagFPmOogFEJFsUTO6eF/view?usp=drive_link

ref_3:
https://drive.google.com/file/d/14YRssyg1a7NOxAh6G4iSKqetdxTRRkpj/view?usp=drive_link

ref_2:
https://drive.google.com/file/d/1y5Qd-KbhR4a6UXHa0SryyC8uZCN2yDOz/view?usp=drive_link

ref_1:
https://drive.google.com/file/d/1UOQXSjyBvD0ee8Mkmum4yL2TNQ9rdU6o/view?usp=drive_link


On Mon, Nov 4, 2024 at 12:31 PM Enock Seth Nyamador via Talk-gh <
talk-gh at openstreetmap.org> wrote:

> Dear Hajar and TomTom (mappers),
>
> In reference to my comments on your maxspeed=* mapping in Accra [1].
> There are multiple frightening maxspeed=* from this mapping which are
> completely unverifiable. I also see roads which of course lead nowhere
> and were results of other organised mapping campaigns tagged with
> maxspeed=* without any further investigation.
>
> I would have expected that this kind of organised mapping is discussed
> publicly and documented on the OSM Wiki.  As of 2024-08-23, there is
> only one road in Accra on OSM with verifiable speed limit of 100 km/h
> [2]. Seeing roads in dense Accra Central even with existing adjacent
> verifiable maxspeed=50 tagged with higher maxspeed=90/100 [3][3a] makes
> me wonder. I have also seen lower maxspeed values where there exist some
> street-level images to validate eg. way [4] (maxspeed=30) and Mapillary
> image [5] (street sign 50).
>
> TomTom's mapping team I believe is better aware and in the position to
> post-process all roads wherever and add whatever desired speed, see
> Default speed limits [6], but outsourcing to a bunch of newbies to add
> into OSM, is not what OpenStreetMap is about.
>
> As I have always commented on this list and elsewhere there is just too
> much useless data from many undocumented organised mapping activities in
> Ghana that needs to be deleted in the end, hence we don't want to see
> new problems that will never be fixed.
>
> The practice of setting up a series of maproulette or HOTOSM Tasking
> manager instance projects and letting it fix itself is not helping but
> continues take place from multiple actors in Ghana and elsewhere.
>
> Please kindly find the best way to undo all maxspeed=* resulting from
> this organised mapping campaign without damaging existing valid ones
> e.g. manually, contact DWG, etc.
>
> 1. https://maproulette.org/browse/challenges/48926
> 2. https://overpass-turbo.eu/s/1TCn
> 3.
>
> https://www.openstreetbrowser.org/#map=17/5.54911/-0.20774&basemap=osm-mapnik&categories=car_maxspeed
> 3a
> <https://www.openstreetbrowser.org/#map=17/5.54911/-0.20774&basemap=osm-mapnik&categories=car_maxspeed3a>.
> https://overpass-turbo.eu/s/1TCC
> 4. https://www.openstreetmap.org/way/169135203/history/7
> 5.
>
> https://www.mapillary.com/app/?lat=5.551382553813923&lng=-0.19400795959847983&z=19.9&pKey=517473239420891&focus=photo
> 6. https://wiki.openstreetmap.org/wiki/Default_speed_limits
>
> Best,
> Enock
>
>
> _______________________________________________
> Talk-gh mailing list
> Talk-gh at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-gh
>


-- 
Stephen Mawutor Donkor
M: +233 (020) 8254044
T: @stevdok
S: stevdok


*"Mere philosophy will not satisfy us.We cannot reach the goal by mere
words alone.Without practice, nothing can be achieved" - Sri S.
Satchidananda*
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