[OSM-talk] "Incorrect speed limit" anonymous notes - who is behind that?

[Peter Wendorff]

Hi Shaun,

if I understand these maps correctly, they show streets without a
maxspeed tag, but not msising maxspeed restrictions under the assumption
of a national default or something like that (although it seems not so
show any "missing maxspeed" in Germany, so there might be something like
that applied).

If maxspeed is and should be applied on any street, this works, but only
until speed limits change.
If you imply the default according to highway class and location, it
fails as many roads do follow these defaults and cannot be counted as
"missing", nor is it possible to decide where else a maxspeed is missing
then.

In any case reporting missing maxspeeds will work only until the speed
limit is changed on the ground as it is even more difficult (if
possible) to detect where there are errors (!) in existing speed limits.

regards
Peter

Am 29.07.2014 um 13:10 schrieb Shaun McDonald:
> Hi Peter,
> 
> The following ITO Map shows missing maxspeed tags where there isn’t any purple (mph maxspeed) or dark green (km/h maxspeed) colour:
> http://www.itoworld.com/map/125?lon=-0.08316&lat=51.51851&zoom=14&open_sidebar=map_key&fullscreen=true
> 
> If you want to see the current speed limits see:
> http://www.itoworld.com/map/124?lon=-0.08316&lat=51.51851&zoom=14&open_sidebar=map_key&fullscreen=true
> 
> Clicking the maps gives more info in the sidebar.
> 
> Shaun
> 
> Disclaimer: Employee of ITO World who produce the maps above.
> 
> On 29 Jul 2014, at 11:49, Peter Wendorff <wendorff at uni-paderborn.de> wrote:
> 
>> Sorry,
>> there are QA tools to detect where speed limits are missing?
>> Can you give me a link?
>> And - if it's not self explaining: how should that work? I don't see any
>> way to detect missing speed limits in the data beyond cases where those
>> are implicit defaults, like 100 on non-trunk roads away from built up
>> areas in Germany (which is complicated enough to derive from the data),
>> or 130 for trunk roads (although most often there are lower limits), or
>> 50 in cities (as the most often down-signed default).
>>
>> So if there is any QA tool that detects that, I fear it uses third party
>> sources, a reporting system similar to the notes feature, but using a
>> different channel, or it is restricted to some cornercases only. I doubt
>> there is something like that which could make notes about speed limit
>> errors in osm obsolete.
>>
>> IMHO notes are to be checked in person on the ground usually. If there's
>> nobody in France to do that, yes, then notes will remain in the database
>> for a long time, but basically they stay correct: Here is something
>> missing or wrong, please check that on the ground.
>>
>> regards
>> Peter
>>
>> Am 29.07.2014 um 11:09 schrieb JB:
>>> I don't necessarily want to analyse once more how the notes are opened,
>>> closed or not closed and to what aim, nor analyse the end of
>>> OpenStreetBug life and the quality of the remaining bugs, but in France,
>>> I have never ever seen anyone comment on someone else's note (or «
>>> resurvey »). The only comments I have seen were from the note opener,
>>> when prompted by a potential corrector.
>>>
>>> So a note which indicates « probably 90km/h here » or « speed limit is
>>> not 0km/h » may remain there for years (yes, years), demotivate
>>> potential note closers, never be closed. I do not think they participate
>>> to a high quality note db. There are quality assessments tools around
>>> that allow contributors to detect where speed limits are missing.
>>>
>>> JB, with perhaps some bad faith in there, but not that much.
>>>
>>>
>>> Le 29/07/2014 10:19, Steve Doerr a écrit :
>>>> On 29/07/2014 08:32, JB wrote:
>>>>
>>>>> Anyway, as for most notes concerning speed limits, if you do no have
>>>>> the beginning and the end of the limit, at least in France, the
>>>>> information is quite useless.
>>>>
>>>> Are we all armchair mappers now? Surely the note should prompt someone
>>>> local to go out to the location and find out where the speed limit
>>>> starts and ends?
>>>>
>>>
>>>
>>> _______________________________________________
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>>> https://lists.openstreetmap.org/listinfo/talk
>>>
>>
>>
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>