[Talk-gh] Unverifiable speed limits resulting from organised mapping in Accra
Enock Seth Nyamador
open at enockseth.co
Tue Nov 5 10:35:59 UTC 2024
We all learn and make mistakes but some mistakes are avoidable and
should be avoided. In this organised mapping campaign the information in
the field seems to be/have been overwritten by regulation in the
presence of existing street signs.
If we are going to rely on regulations for places where there are no
street signs we should do it in a documented and controlled manner to
help other mappers. But tagging every single way based on their physical
classification and/or doesn't even lead anywhere/exist with maxspeed=*
just doesn't seem to help.
Best,
Enock
On 05.11.24 10:52, Stephen Mawutor Donkor wrote:
> For your reference
>
> 1 Ghana Driver’s Guide ** make reference to page 3.
> https://mrh.gov.gh/wp-content/uploads/2022/09/Ghana-Drivers-Guide-_Final_Signed.pdf
>
> 2 Speed limits on Ghana roads
> https://www.youtube.com/watch?v=7flkwDk2Buc
>
> for all other references which were not accessible from my earlier
> email see below.:
>
> https://drive.google.com/file/d/181DZYKNOA-ispSR-tEqyRLFmizzKPLvp/view?usp=sharing
>
> Regards
>
> On Mon, Nov 4, 2024 at 6:33 PM Enock Seth Nyamador via Talk-gh
> <talk-gh at openstreetmap.org> wrote:
>
> Hi Mawutor and TomTom,
>
> My comments are not meant to be in anyway harsh towards any person or
> group of persons. Unfortunately, I only tell about the reality of the
> results of such mapping campaigns which tend reside in OSM for who
> knows
> how long. It is ok to know that some communication have been done
> with
> the community in Ghana but where is this publicly? Any OSM wiki
> page or
> discussions? I am afraid to say if some regulation say roads in urban
> areas are eg. 30 km/h doesn't mean we should assume and map all roads
> with 30 km/h, even if there are no existing street signs or on roads
> that lead nowhere. How do other mappers verify these contributions?
>
> I must say issues need not arise always, most of them can be
> easily and
> should be avoided. We can make OpenStreetMap better if these kinds of
> mapping are discussed in the wider community, well documented,
> avoided
> or corrected in their early stages.
>
> Unfortunately, the references you shared are not accessible.
>
> Best,
> Enock
>
> On 04.11.24 17:38, Stephen Mawutor Donkor wrote:
> >
> > 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
> <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://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
> <https://www.mapillary.com/app/?lat=5.551382553813923&lng=-0.19400795959847983&z=19.9&pKey=517473239420891&focus=photo>
> >
> <https://www.mapillary.com/app/?lat=5.551382553813923&lng=-0.19400795959847983&z=19.9&pKey=517473239420891&focus=photo
> <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
> >
> >
> > _______________________________________________
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> > 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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>
>
>
> --
> 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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