[Tagging] [OSM-talk] Should we map things that do not exist?

[Mateusz Konieczny]

Jun 8, 2020, 16:11 by pla16021 at gmail.com:

> On Mon, 8 Jun 2020 at 14:08, Mateusz Konieczny via Tagging <> tagging at openstreetmap.org> > wrote:
>  
>
>> I added explicit "even if rails are gone".
>>
>
> Thank you.
>
>
>> "the way will still be visible from the ballast that remains."
>>
>> Can you find a good photo of that on >> https://commons.wikimedia.org/>>  ?
>> I would add it to examples.
>>
>
> https://commons.wikimedia.org/wiki/File:Restos_del_Balastro_de_la_linea_ferrea_Cuatro_Vientos_-_Leganes.JPG
>
Added.

>
> There may be other indicators of older lines: > https://commons.wikimedia.org/wiki/File:Stone_sleepers_at_Bugsworth_basin_-_geograph.org.uk_-_450090.jpg
>
Not sure whatever I am understanding description correctly - it is part
of railway infrastructure for narrow gauge rail pulled by horses, right?

> Also, it is common in my part of the world for older roads, bridleways,
> railways, some farm tracks and even some footpaths to have tree-lined
> hedges.  They're obvious from aerial imagery, although it may not always
> be apparent what type of way they enclose.
>
If anyone finds image on Wikimedia Commons - please link it here (or just add it to a wiki)

>
>
>>> Erm, what about cases where a road or footpath or cycleway has been constructed
>>> along the old line and we know that because it is mentioned on current websites?
>>>
>>  
>>
>> Describe it as part where different mappers have different opinions? 
>>
>
> Sounds reasonable to me.
>
:)

>> I guess that some people would want to map this, for me it is case of copying maps of historic data.
>>
>
> What, in principle, are the differences between historic maps, a website documenting
> that a route has been constructed over an old railway line and a sign at the start of
> the route saying that it follows the path of an old railway line?
>
Is it a sole indicator that route follows former railway line?

Then in all cases I think it is a case of 
"feature is so gone/degraded that it is no longer identifiable based on survey,
requires import of external data to identify it"

I would map it as a property of route (follows_former_railway=yes or something)
if I would want to map that, but if there are no longer existing traces of railway
I would not map former railway itself
(similarly I would be fine with mapping cycling route following route took by some
ancient army and tag is as battle-related and so on, but I would not map track took by army
- cycleway route is verifiable, but route took by army is not)


>> (the tricky part is that both of us have strong opinion here
>>
>
> Do we?  I'm not sure that I would map a razed railway line where no trace of any
> of it remains.  I'm not sure if I would map a short section of line that has been
> built over and no trace remains if there were clear traces of the rest of it, but
> I wouldn't remove it if somebody else had mapped it.
>
Heh, I just reverted change to Wiki that claimed that local communities may decide to
forbid mapping of railways with clear remains and may allow to map ones where all traces
were completely utterly and totally eradicated.
( https://wiki.openstreetmap.org/w/index.php?title=Demolished_Railway&diff=1998630&oldid=1998621 )

>> and it is tricky to distinguish case of "person is representing silent 
>>
>> mappers not participating in discussion" and "person has fringe opinion 
>>
>> not shared by anybody").
>>
>
> We don't have humming.  The best we can do is note that several people
> have expressed differing opinions and that the matter is contentious.  We
> can also note that certain edge cases have been highlighted.  I'm with Volker
> on this one: at this point in the conversation it is unhelpful for the wiki to
> be changed to state that these things should be removed whenever they
> are discovered.
>
I think that for
"Here railway is gone without any clearly identifiable trace in terrain."
case it is OK to have 
"should not be mapped and can be deleted if mapped."
("can be deleted" was just changed from "should be")

Also - it is OK to have
https://wiki.openstreetmap.org/wiki/File:Galeria_Kazimierz.JPG
example with
"Location of a former railway and railway station without any
traces whatsoever. Not mappable."
?
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