Re: [OSM-talk] razed railways and other things that don't exist today

[stevea]

Thank you, Warin, thank you Mike, thank you Zeke:  With Warin's 
"clarifications," I think we move closer to something approaching a reasonable 
way to say this.  I would correct "renders" to "renderers," and perhaps change 
it to "OSM's database and renderers...", but aside from that, +1.

> On Dec 11, 2022, at 12:17 AM, Warin <61sundow...@gmail.com> wrote:
> 
> 
> On 6/12/22 06:39, Mike Thompson wrote:
>> 
>> 
>> On Mon, Dec 5, 2022 at 11:22 AM Minh Nguyen via talk 
>>  wrote:
>> Vào lúc 09:55 2022-12-05, Zeke Farwell đã viết:
>> > That is a good summary, though "Once the OSM available satellite imagery 
>> > does not show the feature" 1) There are other sources that an armchair 
>> > mapper can use other than imagery, such as the Strava Global Heatmap, the 
>> > USGS 3 DEP data (in the US), and GPX data that has been uploaded to the 
>> > OSM server.
>> 2) The term "satellite imagery" also excludes street level imagery, such as 
>> Mapillary
>> 3) Technically some of the imagery we refer to as "satellite" is really 
>> "aerial." 
>> 
>> "Once the feature truly no longer exists and is no longer evident in any of 
>> the available remote sources commonly used to edit OSM, including overhead 
>> imagery (satellite/aerial/drone), street level imagery (e.g. Mapillary), GPS 
>> traces/heatmaps (e.g. Strava), and elevation data (e.g. USGS 3DEP) the 
>> feature can be deleted"
>> 
>> 
> 
> I have abbreviated the above to be;
> "The following tags function is to reduce the possibility of a mapper 
> remapping the feature from existing available sources used to edit OSM, e.g. 
> satellite or aerial imagery, that shows the old state of the feature. Once 
> the OSM available sources do not show the feature, the feature can safely be 
> removed from OSM. Renders cannot rely on OSM preserving physically vanished 
> history. "
> 
> I don't want to use too many words .. so as not to obscure the basic 
> intention. Listing all the possible sources is not necessary... 


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Re: [OSM-talk] razed railways and other things that don't exist today

[Warin]

On 6/12/22 06:39, Mike Thompson wrote:



On Mon, Dec 5, 2022 at 11:22 AM Minh Nguyen via talk 
 wrote:


Vào lúc 09:55 2022-12-05, Zeke Farwell đã viết:
> That is a good summary, though "Once the OSM available satellite
imagery
> does not show the feature"

1) There are other sources that an armchair mapper can use other than 
imagery, such as the Strava Global Heatmap, the USGS 3 DEP data (in 
the US), and GPX data that has been uploaded to the OSM server.
2) The term "satellite imagery" also excludes street level imagery, 
such as Mapillary
3) Technically some of the imagery we refer to as "satellite" is 
really "aerial."


"Once the feature truly no longer exists and is no longer evident in 
any of the available remote sources commonly used to edit OSM, 
including overhead imagery (satellite/aerial/drone), street level 
imagery (e.g. Mapillary), GPS traces/heatmaps (e.g. Strava), and 
elevation data (e.g. USGS 3DEP) the feature can be deleted"






I have abbreviated the above to be;

"The following tags function is to reduce the possibility of a mapper 
remapping the feature from existing available sources used to edit OSM, 
e.g. satellite or aerial imagery, that shows the old state of the 
feature. Once the OSM available sources do not show the feature, the 
feature can safely be removed from OSM. Renders cannot rely on OSM 
preserving physically vanished history. "



I don't want to use too many words .. so as not to obscure the basic 
intention. Listing all the possible sources is not necessary...
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Re: [OSM-talk] razed railways and other things that don't exist today

[Mike Thompson]

On Mon, Dec 5, 2022 at 11:22 AM Minh Nguyen via talk 
wrote:

> Vào lúc 09:55 2022-12-05, Zeke Farwell đã viết:
> > That is a good summary, though "Once the OSM available satellite imagery
> > does not show the feature"

1) There are other sources that an armchair mapper can use other than
imagery, such as the Strava Global Heatmap, the USGS 3 DEP data (in the
US), and GPX data that has been uploaded to the OSM server.
2) The term "satellite imagery" also excludes street level imagery, such as
Mapillary
3) Technically some of the imagery we refer to as "satellite" is really
"aerial."

"Once the feature truly no longer exists and is no longer evident in any of
the available remote sources commonly used to edit OSM, including overhead
imagery (satellite/aerial/drone), street level imagery (e.g. Mapillary),
GPS traces/heatmaps (e.g. Strava), and elevation data (e.g. USGS 3DEP) the
feature can be deleted"

>
>
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Re: [OSM-talk] razed railways and other things that don't exist today

[Minh Nguyen via talk]

Vào lúc 09:55 2022-12-05, Zeke Farwell đã viết:
That is a good summary, though "Once the OSM available satellite imagery 
does not show the feature" is perhaps a bit too strict.  Some things 
aren't always visible or clear from aerial imagery and need to be 
surveyed in person.  I'm sure the intent of this phrase is not to 
encourage people to delete anything they can't see on aerial imagery, 
but it could be interpreted that way.


Yes, there have been several disputes between editors because of this 
exact scenario.


Also, I often need to keep a disused:shop=* around because the newest 
street-level imagery in an area is from before the shop closed. 
Sometimes mappers can be complacent about street-level imagery being 
fresher or more ground-truthy than aerial imagery, but this is not 
necessarily the case.


--
m...@nguyen.cincinnati.oh.us



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Re: [OSM-talk] razed railways and other things that don't exist today

[Zeke Farwell]

That is a good summary, though "Once the OSM available satellite imagery
does not show the feature" is perhaps a bit too strict.  Some things aren't
always visible or clear from aerial imagery and need to be surveyed in
person.  I'm sure the intent of this phrase is not to encourage people to
delete anything they can't see on aerial imagery, but it could be
interpreted that way.

--
Zeke

On Mon, Dec 5, 2022 at 7:59 AM Mateusz Konieczny via talk <
talk@openstreetmap.org> wrote:

> I would mention
>
> - it is OK to temporarily map ones not visible on aerial images but likely
> to be mistakenly
> remapped
> - "can safely be removed" - would change that it not only can be removed,
> but also
> should be removed
>
>
> 5 gru 2022, 11:26 od 61sundow...@gmail.com:
>
> I have placed what I believe is a summary of this discussion on the OSM
> wiki for lifecycle
>
> It reads
>
> "The following tags function is to reduce the possibility of a mapper
> remapping the feature from existing satellite imagery that shows the old
> state of the feature. Once the OSM available satellite imagery does not
> show the feature the feature can safely be removed from OSM. Renders cannot
> rely on OSM preserving physically vanished history."
>
> There after follow the tags 'demolished', 'removed', 'destroyed' and
> 'razed'.
>
> https://wiki.openstreetmap.org/wiki/Lifecycle_prefix#Stages_of_decay
>
>
> If there are any further thoughts or even corrections to my text above
> then please post them here.
>
>
> My own thoughts?
>
> I have not placed any warning about mechanical edits to seek these out as
> enough warning is evident in the requirement for it to be not shown in the
> OSM satellite imagery, which would discourage me so I think it will work
> with others.
>
>
>
>
>
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Re: [OSM-talk] razed railways and other things that don't exist today

[Mateusz Konieczny via talk]

I would mention

- it is OK to temporarily map ones not visible on aerial images but likely to 
be mistakenly
remapped
- "can safely be removed" - would change that it not only can be removed, but 
also
should be removed


5 gru 2022, 11:26 od 61sundow...@gmail.com:

> I have placed what I believe is a summary of this discussion on the OSM wiki 
> for lifecycle
>
> It reads
>
> "The following tags function is to reduce the possibility of a mapper 
> remapping the feature from existing satellite imagery that shows the old 
> state of the feature. Once the OSM available satellite imagery does not show 
> the feature the feature can safely be removed from OSM. Renders cannot rely 
> on OSM preserving physically vanished history."
>
> There after follow the tags 'demolished', 'removed', 'destroyed' and 'razed'.
>
> https://wiki.openstreetmap.org/wiki/Lifecycle_prefix#Stages_of_decay
>
>
> If there are any further thoughts or even corrections to my text above then 
> please post them here.
>
>
> My own thoughts?
>
> I have not placed any warning about mechanical edits to seek these out as 
> enough warning is evident in the requirement for it to be not shown in the 
> OSM satellite imagery, which would discourage me so I think it will work with 
> others.
>
>
>
>
>
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>

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Re: [OSM-talk] razed railways and other things that don't exist today

[Warin]

I have placed what I believe is a summary of this discussion on the OSM 
wiki for lifecycle


It reads

"The following tags function is to reduce the possibility of a mapper 
remapping the feature from existing satellite imagery that shows the old 
state of the feature. Once the OSM available satellite imagery does not 
show the feature the feature can safely be removed from OSM. Renders 
cannot rely on OSM preserving physically vanished history."


There after follow the tags 'demolished', 'removed', 'destroyed' and 
'razed'.


https://wiki.openstreetmap.org/wiki/Lifecycle_prefix#Stages_of_decay


If there are any further thoughts or even corrections to my text above 
then please post them here.



My own thoughts?

I have not placed any warning about mechanical edits to seek these out 
as enough warning is evident in the requirement for it to be not shown 
in the OSM satellite imagery, which would discourage me so I think it 
will work with others.






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Re: [OSM-talk] razed railways and other things that don't exist today

[Mateusz Konieczny via talk]

Oct 26, 2022, 12:05 by dieterdre...@gmail.com:

>
>
> sent from a phone
>
>> On 26 Oct 2022, at 11:45, Mateusz Konieczny via talk 
>>  wrote:
>>
>> Note that when you found some gone railway
>> mapped in OSM then it is useful
>>
>> - edit OSM object to note which traces are left if any
>> (ideally, it would be done by original mapper)
>>
>> - or delete nonexistent sections without traces
>>
>
>
> what is the scale/resolution  for determining a “non-existent” section? If 
> you do it too fine grained, it would be like mapping a dashed divider line, 
> with yes/no alternating every 2 meters.
>
If road was rebuild and as result there is 10m wide gap where embankment 
was obliterated then I would delete such section of 
railway=abandoned/railway=razed

But if someone would initially map it then I would not complain about it

> Is a former station a trace that is valid in this sense?
>
if train station/platform trace remains then mapping them is fine

but if railway track between them is obliterated without trace then such track
is not mappable and should be deleted if it is mapped

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Re: [OSM-talk] razed railways and other things that don't exist today

[Minh Nguyen]

Vào lúc 16:41 2022-10-26, Zeke Farwell đã viết:
On Wed, Oct 26, 2022 at 1:11 PM Greg Troxel > wrote:



I think people should keep in mind that a culture of deltionism is
demoralizing to contributors and harms OSM more than a few  marginal
items in the database.


This is a fair point, but given how often this comes up, it doesn't seem 
like it's just a few marginal items.  Also it's just as demoralizing for 
a well intentioned mapper who maps an area and removes some former 
railway in the process to then get berated for it.


I also agree with stevea@ -- old railways are usually visible in the
landscape, and the data about where they were in between visible places
seems more useful than harmful.


There is no question that the data about the location of former railways 
is useful.  However, data being useful is not the standard for inclusion 
in OSM.  We map the world as it exists today and this excludes plenty of 
useful data.  Former features that no longer exist are simply out of 
scope for OSM .


Also note that people who do not like railroads often do not see the
evidence as well as people who are used to looking for it.


I support mapping old rail beds as railway=razed where they are visible 
in forests, fields, and other open land.  These traces are often not 
visible to those with an untrained eye and that's certainly an issue.  
However, I draw the line at sections going through buildings, highways, 
excavated areas, or under water where there really are no visible traces 
by any reasonable standard.  In these situations, a person with a 
trained eye may see clues and patterns leading them to the deduction 
that a railway used to be there, but this is not the same as visible 
remnants.  This is mapping something that is really no longer there in 
any meaningful way.


I've deduced underground pipelines by similar methods, for example a 
natural gas pipeline that obviously follows a road as it crosses 
multiple streams above the ground. But I've done so with confidence that 
the visible portions must be connected somehow. There's much less reason 
to assume that the traces of a former railway continue to be connected 
below newer development. The pipeline would also be marked at regular 
intervals, so there's a strong possibility that a field mapper could 
improve upon the geometry that I've mapped from an armchair.


One could describe footway=crossing crossing=unmarked ways as another 
kind of deduced feature, connecting sidewalks on either side of an 
intersection. But there's a practical justification for their inclusion 
(routability), as well as a legal justification in some regions.


Some historic railway mappers would quibble at the notion that they're 
merely connecting the dots. Over the years, I've heard some rather 
tortured arguments, forcefully delivered, about these ways being the 
result of intense surveying. I tip my hat to anyone willing to devote 
their time to finding mappable railroad spikes via metal detector. 
However, we should expect them to document their findings meticulously, 
beyond just tagging source=survey on a railway=* and expecting to be 
consulted when it comes up for deletion many years later.


Personally, I never got into abandoned/razed railway mapping until I 
started contributing to OpenHistoricalMap. Former railroads are 
impossible to ignore when detailing the histories of so many towns 
across the U.S. Indeed, their remnants are all over the place; it's fun 
to realize that a tree line or embankment that you always took for 
granted fits into a hidden puzzle of former railroads. As a layperson, 
I'm only able to make these connections because of historic maps, 
photos, and timetables, the kinds of sources that are irrelevant to OSM 
but central to OHM.


I think historic railroad mappers who limit themselves to OSM's 
railway=abandoned/razed tags are missing out. Why not map the whole rail 
network as it was, unapologetically? In the areas where I map, OHM 
already has more former railroads than OSM will ever have, even despite 
the real ergonomic issues mentioned earlier in this thread.


--
m...@nguyen.cincinnati.oh.us



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Re: [OSM-talk] razed railways and other things that don't exist today

[Martin Koppenhoefer]

sent from a phone

> On 27 Oct 2022, at 01:44, Zeke Farwell  wrote:
> 
> I support mapping old rail beds as railway=razed where they are visible in 
> forests, fields, and other open land.  These traces are often not visible to 
> those with an untrained eye and that's certainly an issue.  However, I draw 
> the line at sections going through buildings, highways, excavated areas, or 
> under water where there really are no visible traces by any reasonable 
> standard.



New buildings standing on top are often brought up as the point where predating 
features at the same spot should be considered disappeared, but this is not an 
universal criterion, indeed I very often see traces of former features in the 
gardens, entrance areas and basements of buildings. The more massive a 
structure was, the more likely you’ll probably find some remains.
Here’s an example of some former city walls visible in a shop window: 
https://3.bp.blogspot.com/-OnUPS1SpI3g/WPYNxl4EFXI/Jjg/nNTpu2-J4u4MYR1dDGPMhHP4zdd_n6IQQCLcB/s1600/17990776_1335536786482546_2806219406469521007_n.jpg
 (this is from the “first” city wall (severian) of which not so much is still 
visible today)

An example for more recent remains: some time ago you could still see in Berlin 
(before they actually reconstructed the current fake version) a few street 
lamps attached  to buildings that were formerly 
 used for illuminating the Wall, although the wall itself had been “completely” 
demolished. Not recognizable for everyone, but clearly visible traces if you 
knew to read them.

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Re: [OSM-talk] razed railways and other things that don't exist today

[Zeke Farwell]

On Wed, Oct 26, 2022 at 1:11 PM Greg Troxel  wrote:

>
> I think people should keep in mind that a culture of deltionism is
> demoralizing to contributors and harms OSM more than a few  marginal
> items in the database.
>

This is a fair point, but given how often this comes up, it doesn't seem
like it's just a few marginal items.  Also it's just as demoralizing for a
well intentioned mapper who maps an area and removes some former railway in
the process to then get berated for it.


> I also agree with stevea@ -- old railways are usually visible in the
> landscape, and the data about where they were in between visible places
> seems more useful than harmful.
>

There is no question that the data about the location of former railways is
useful.  However, data being useful is not the standard for inclusion in
OSM.  We map the world as it exists today and this excludes plenty of
useful data.  Former features that no longer exist are simply out of scope
for OSM .


> Also note that people who do not like railroads often do not see the
> evidence as well as people who are used to looking for it.
>

I support mapping old rail beds as railway=razed where they are visible in
forests, fields, and other open land.  These traces are often not visible
to those with an untrained eye and that's certainly an issue.  However, I
draw the line at sections going through buildings, highways, excavated
areas, or under water where there really are no visible traces by any
reasonable standard.  In these situations, a person with a trained eye may
see clues and patterns leading them to the deduction that a railway used to
be there, but this is not the same as visible remnants.  This is mapping
something that is really no longer there in any meaningful way.

 --
Zeke
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Re: [OSM-talk] razed railways and other things that don't exist today

[Greg Troxel]

Frederik Ramm  writes:

> you are correct in all aspects, however in the spirit of friendly
> collaboration I would say that a limited amount of
> stuff-that-should-not-be-in-OSM can be *tolerated*. If someone does a
> lot of good work for OSM otherwise and would really like to record an
> ancient former railroad that ran through where their house now sits -
> I shrug and let them do it. Only if someone starts to make it their
> mission to map every ancient railroad in the country and/or create
> relations so that you can see where trains used to ride in 1848 is
> when I'll ask them to stop and find a better place for it.

Well said.

I think people should keep in mind that a culture of deltionism is
demoralizing to contributors and harms OSM more than a few  marginal
items in the database.

I also agree with stevea@ -- old railways are usually visible in the
landscape, and the data about where they were in between visible places
seems more useful than harmful.

Also note that people who do not like railroads often do not see the
evidence as well as people who are used to looking for it.

> I would stress "not adding more of this" over "removing the stuff that
> already is in OSM" though. I don't want a horde of self-appointed
> cleaners running through OSM "because the wiki says so".

Good point.   "Deletionists double-plus bad".


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Re: [OSM-talk] razed railways and other things that don't exist today

[stevea]

Some historical perspective on a project like OSM, its growth, the social 
aspects of "what that means and does to tagging" over time might be helpful.  
The dates and numbers I'm about to offer as examples are wholly illustrative 
(and indicate not arithmetic, but geometric growth, a very powerful force) and 
are no way based in reality because I've "done the research on the actual 
numbers," because I haven't.  I'm simply making a point or two.

Let's say early in OSM's history, oh, 2005 or so, there were 10 mappers 
worldwide who began the first tendrils of rail mapping, and that by 2006 that 
grew to 50.  People in sizes like that can talk to each other and agree on 
things to a 100% level of agreement, or pretty close to 100%.  This is because 
the "problem set" has a small enough size that its "solution set" can be hashed 
out in a few emails, not many kilobytes of wiki, and heads nod in almost 
perfect unison among a relatively small group of people.  If you are "in the 
club," it's easy, and even quite fun!

By 2007 (and, for example, the USA's TIGER Import of hundreds of thousands of 
km of rail) there are 500 active, enthusiastic rail mappers in OSM, and lots of 
work to do, and it feels like maybe "1% of the problem" (of mapping all of 
Earth's rail accurately) has barely had its surface scratched.  On the social 
dimension, this remains manageable, especially as things fragment in to 
different countries, and hundreds of people still might only be a couple, a 
few, or maybe at most a dozen, even in a very complex rail area (like Germany 
or greater Europe):  "localization of the solution space" really does help a 
lot.  This remains doable, but people eye the future and imagine public 
transport and better renderers, and so allow a timeline of a few years for 
these things to develop.  It remains relatively easy, especially if you "remain 
local / regional," and "others (clever ones, busy ones, more-curious ones...) 
"think globally."  OSM is fine.

Fast forward to 2010-11 and now there are many thousands of rail mappers and 
things like PTv2 move from "good ideas" to "coming on strong," OpenRailwayMap 
gets rolling, major differences in how rail all over the world show that the 
problem is large, maybe quite difficult if people are honest, and yet it 
remains manageable as the tools get better and the numbers, while growing and 
at least medium-sized, are not totally overwhelming.

I can go on with real life examples (from this time period of 2014-16-18-20-22, 
and personally, as I've given SOTM talks, one on rail...) and had a fair bit to 
do and say about "rail growth in OSM" in my own country (USA), I've seen this 
growth — geometric growth — and how it has had to cope with rail over the 
one-to-two centuries this transport technology has been around (including ORM 
and OHM as examples of how OSM "maps" it, both logically and literally).  There 
are now hundreds of thousands of rail mappers in OSM, in over a hundred 
countries.  Think of the "social dimensions" of not only "that" but "how that 
has grown and continues to grow."  The amount of fragmentation of understanding 
(especially given humans' many languages and both the limitations of using 
English and the "Balkanization" of isolated language communities) has now 
become quite large...maybe "huge" by some people's estimation.  Logically 
mapping how we have, do and will put "razed" (demolished...all the other 
flavors) of "doesn't (completely) exist today" rail into tagging schemes that 
we all agree upon, especially given that many don't have OSM's now-decades-long 
historical perspective of "how things (like tagging) have grown up w.r.t. rail 
in our project" are now "difficult," but remain explainable and doable.  I 
believe we are up to the task, but it is complex, the geometric growth 
compounds this, so do the relatively long (in software-, data-project world 
sense) timescales, and especially (in a project like OSM), the social 
dimensions (of consensus, multilingualism and so on).  We (all of us in OSM who 
might map rail and other things "that don't exist today") are still "in the 
club," but it is less easy to talk amongst ourselves about why we "do this" 
(but "not that").

And, I'm simply talking about "razed railways" (and a bit more).  It's big and 
complex, and doesn't "shoehorn" (get forcefully or uncomfortably crammed) very 
well into a small box.

Now, please understand there are many, many other topics in OSM which are not 
completely unlike "razed railways" (and why they are an "odd duck" and don't 
seem to categorize well, or need a lot of explaining, or both).

One of my points?  Often, the history of how we got here and oddities of why go 
a long way to explain.  But the natural human desire to understand quickly and 
not necessarily digest all of that makes for quizzical or difficult 
understandings.

Thank you for reading.
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Re: [OSM-talk] razed railways and other things that don't exist today

[Martin Koppenhoefer]

sent from a phone

> On 26 Oct 2022, at 11:45, Mateusz Konieczny via talk  
> wrote:
> 
> Note that when you found some gone railway
> mapped in OSM then it is useful
> 
> - edit OSM object to note which traces are left if any
> (ideally, it would be done by original mapper)
> 
> - or delete nonexistent sections without traces


what is the scale/resolution  for determining a “non-existent” section? If you 
do it too fine grained, it would be like mapping a dashed divider line, with 
yes/no alternating every 2 meters.
Is a former station a trace that is valid in this sense?

Cheers Martin 
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Re: [OSM-talk] razed railways and other things that don't exist today

[Mateusz Konieczny via talk]

Which OSM Wiki pages you checked to find out
reason for existence of things like demolished:building=yes?

Recently demolished building may be visible on aerial images

Using lifecycle prefixes it is possible to clearly mark that specific object 
must not be
remapped without proper verification.

Once there is no real risk of remapping them by person thinking that this 
objects
are still existing such elements should be deleted from OSM.

Fully gone elements (for example levelled railway embankment replaced by
residential buildings) should be deleted from OSM.

Is there any OSM Wiki page claiming otherwise?

> it is used by Open Railway Maps (ORM)

If they want to display also fully gone railway tracks -
then they need to use OpenHistoricalMap dataset

If they use OSM then they will show only recently
demolished one and ones that left traces.

Some incorrectly mapped ones may be displayed,
but they may be correctly deleted at any moment
once this mistakes are spotted.

-

Note that when you found some gone railway
mapped in OSM then it is useful

- edit OSM object to note which traces are left if any
(ideally, it would be done by original mapper)

- or delete nonexistent sections without traces
and review edits that added them.
It is common to see changeset adding
400km of destroyed railway without any verification
in place, in such case entire changeset should be
reverted.
Obviously in case of any doubt - comment using
changeset comment and create OSM note,
then get back to it in some time
( https://www.openstreetmap.org/note/3412415
is my latest one, spotted it while mapping something else)

Without doing this mappers of railways gone without
any trace will easily win. They copy from old
maps and can easily mark hundreds of kilometers
in one edit.
Sometimes they demand to prove nonexistence
of railways.
But it is fine to remove entire edit if it was done
without survey and added features not
existing in any way on the ground.

Oct 25, 2022, 09:42 by 61sundow...@gmail.com:

> Hi,
>
> Question:
>
> If OSM is about mapping what exists today .. why have the tags that mean 
> there is nothing left of it?
>
>
> demolished:*=*
>     Not existing anymore because of active removal
>  removed:*=*
>     Not existing anymore because of active removal (possible duplicate of 
> demolished:*=*)
> razed:*=*
>     Not existing anymore because of active removal (duplicate of removed:*=*, 
> possible duplicate of demolished:*=*)
> destroyed:*=*
>    Destroyed by an event other than active demolition
>
> I think these tags would be of use in Open Historic Map (OHM) and that is 
> possibly why they are in the OSM wiki?
>
> Possibly the OSM wiki should recommend that the data with these tags be moved 
> to OHM?
>
>
> The argument for mapping these things from the 'old railway' people is that;
>
> 1) it does not render on the 'standard map' so it is not a problem.
>
> 2) it is used by Open Railway Maps (ORM)
>
>
> My contention is;
>
> 1a) This is a problem when people try to map new things, the old things lead 
> to mapping things that never existed like railway=crossing where a new 
> footway/highway is also mapped over a now non existent railway line.
>
> 1b) People mapping new things may not see the old stuff on the new imagery .. 
> and simply delete it, leading to edit wars.
>
> 1c) People map things like an old embankment for old railway lines .. right 
> through existing roads
>
> 3) Old data should be mapped into OHM so it can be preserved .. together with 
> the start and stop dates .. these 2 tags are fairly well ignored in OSM.
>
> 2) ORM should take current data from OSM and old data from OHM. This would 
> add the start/end dates that could be used in ORM to select the time period. 
> Thus those only interested in the present could have that, and those 
> interested in some past date could have that.
>
>
>
>
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Re: [OSM-talk] razed railways and other things that don't exist today

[Marc_marc]

Le 25.10.22 à 19:45, Colin Smale a écrit :
Are underground pipelines and electricity transmission cables just as 
controversial? They are covered over, built on, and completely 
unobservable from the surface


in several European countries, the markers are visible from satellite 
imagery and by survey, this is not at all comparable with a railway line 
that has been dismantled and no longer exists on the ground even if some 
earthworks/cutting are still visible (perhaps a tag would be needed to 
indicate earthworks)




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Re: [OSM-talk] razed railways and other things that don't exist today

[Marc_marc]

Le 25.10.22 à 20:26, Minh Nguyen a écrit :
If you have time to write up your experiences in OHM's central issue 
tracker [1], it could have a concrete impact on the project.


https://github.com/OpenHistoricalMap/issues/issues/478



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Re: [OSM-talk] razed railways and other things that don't exist today

[Frederik Ramm]

Hi,

On 10/25/22 19:18, Brian M. Sperlongano wrote:
In my experience, it is more often the opposite situation that happens.  
A mapper, unaware of the lengthy debates on the topic of former 
railroads, is mapping her house and removes the bit of abandoned rail 
currently on the map in that spot, assuming it is a data error or poor 
import.  After all. she's quite aware that there is a house and not a 
railway at that location as she has personally surveyed it.  Sometime 
later, an abandoned railway enthusiast comes along and angrily harasses 
the mapper for removing the bit of railway that quite rightly isn't 
there.


In that situation, I would clearly support the mapper who has deleted 
the railroad.


(In discussions with abandoned-railway-enthusiasts, you will often get 
to hear that there are remnants of a railway line that betray the former 
existence of it to an educated observer. If a new housing development 
has been built where once there was a railway, then this is obviously 
not a valid line of argument.)


It's been my experience that allowing enthusiasts to map phantom 
railways causes far more grief and contention between mappers than 
simply drawing a line and saying "we don't map things that aren't there."


I agree with that - especially as OSM is very prone to "whataboutism", 
and before you know it there will be a discussion somewhere about 
mapping some other long-gone stuff and people will say "but you allow 
the railways"


Still I would recommend against, and also word any wiki articles to 
avoid, someone starting a crusade to get rid of abandoned railways. 
Delete the ones you encounter while mapping and which you don't see 
traces of - totally fine. Run an overpass query to find them all and 
delete them - just causes unnecessary strife.


Bye
Frederik

--
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Re: [OSM-talk] razed railways and other things that don't exist today

[Minh Nguyen]

Vào lúc 06:40 2022-10-25, Marc_marc đã viết:

when to migrate the data to ohm, I am convinced.
however, having tested it this month, it's horribly non-ergonomic
and I don't believe for a moment that it's within the reach of
an iD contributor nor of an average contributor with josm,
unless a plugin exists, which I haven't seen


Thanks for giving the project a look. In the long term, I think a 
credible OpenHistoricalMap project will be valuable to OSM as an outlet 
for this kind of information that people will inevitably want to map. 
It's good for us to know what we're sending history-minded mappers into.


I'm not surprised that you found major ergonomic issues. OSM 
unsurprisingly gets more attention from software developers than OHM, 
and not all of the OSM software that OHM forks was originally designed 
to be forked. If you have time to write up your experiences in OHM's 
central issue tracker [1], it could have a concrete impact on the project.


Some good news: the iD fork is being redone based on the latest version 
of iD, with more usable customizations than before. [2] The development 
team is working on some deployment issues, but the new version should be 
live soon.


[1] https://github.com/OpenHistoricalMap/issues/issues/
[2] https://github.com/OpenHistoricalMap/iD/pulls?q=is%3Amerged

--
m...@nguyen.cincinnati.oh.us



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Re: [OSM-talk] razed railways and other things that don't exist today

[Brian M. Sperlongano]

On Tue, Oct 25, 2022 at 1:45 PM Colin Smale  wrote:

> Are underground pipelines and electricity transmission cables just as
> controversial? They are covered over, built on, and completely unobservable
> from the surface. They may also have been taken out of service many decades
> ago.
>

In the US, generally no.  They are quite infrequently mapped, and they're
tagged as an underground feature when they are.  That's quite a different
scenario from an ostensibly above-ground feature that is not present to the
above-ground observer.
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Re: [OSM-talk] razed railways and other things that don't exist today

[Colin Smale]

 

> On 25/10/2022 19:18 CEST Brian M. Sperlongano  wrote:
>  
>  
>  
> On Tue, Oct 25, 2022 at 4:37 AM Frederik Ramm  mailto:frede...@remote.org> wrote:
> 
> > in the spirit of friendly collaboration I would say that a limited amount of
> > stuff-that-should-not-be-in-OSM can be *tolerated*. If someone does a
> > lot of good work for OSM otherwise and would really like to record an
> > ancient former railroad that ran through where their house now sits - I
> > shrug and let them do it.
> > 
>  
> In my experience, it is more often the opposite situation that happens.  A 
> mapper, unaware of the lengthy debates on the topic of former railroads, is 
> mapping her house and removes the bit of abandoned rail currently on the map 
> in that spot, assuming it is a data error or poor import.  After all. she's 
> quite aware that there is a house and not a railway at that location as she 
> has personally surveyed it.  Sometime later, an abandoned railway enthusiast 
> comes along and angrily harasses the mapper for removing the bit of railway 
> that quite rightly isn't there. It's been my experience that allowing 
> enthusiasts to map phantom railways causes far more grief and contention 
> between mappers than simply drawing a line and saying "we don't map things 
> that aren't there."
> 
I expect pages with "This page intentionally left blank" save quite a few calls 
to customer service. I.e. if you draw a line and label it somehow "this line 
should not be here" you might defuse the argument and to a point where 
live-and-let-live counts again. Putting an end-date on it might be a start.
 
Are underground pipelines and electricity transmission cables just as 
controversial? They are covered over, built on, and completely unobservable 
from the surface. They may also have been taken out of service many decades ago.
 
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Re: [OSM-talk] razed railways and other things that don't exist today

[Mike Thompson]

On Tue, Oct 25, 2022 at 7:46 AM Marc_marc  wrote:

> Hello,
>
> Le 25.10.22 à 09:42, Warin a écrit :
> > why have the tags that mean there is nothing left of it?
>
> I'm using from time to time as a QA-tag to avoid that a mapper
> add it back

I do this as well.  We have had some major wildfires around where I live,
and a lot of structures were destroyed, yet they still show up in some
imagery sources.  I mark these as destroyed so another mapper doesn't add
them back.

Also trails are constantly being rerouted, and yet the old location will be
shown on imagery and Strava for some time.  Tagging the ols trail with a
life cycle prefix lets other mappers know that what they are seeing on
imagery doesn't match reality.

Mike

>
>
>
>
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Re: [OSM-talk] razed railways and other things that don't exist today

[Brian M. Sperlongano]

On Tue, Oct 25, 2022 at 4:37 AM Frederik Ramm  wrote:

> in the spirit of friendly collaboration I would say that a limited amount
> of
> stuff-that-should-not-be-in-OSM can be *tolerated*. If someone does a
> lot of good work for OSM otherwise and would really like to record an
> ancient former railroad that ran through where their house now sits - I
> shrug and let them do it.


In my experience, it is more often the opposite situation that happens.  A
mapper, unaware of the lengthy debates on the topic of former railroads, is
mapping her house and removes the bit of abandoned rail currently on the
map in that spot, assuming it is a data error or poor import.  After
all. she's quite aware that there is a house and not a railway at that
location as she has personally surveyed it.  Sometime later, an abandoned
railway enthusiast comes along and angrily harasses the mapper for removing
the bit of railway that quite rightly isn't there. It's been my experience
that allowing enthusiasts to map phantom railways causes far more grief and
contention between mappers than simply drawing a line and saying "we don't
map things that aren't there."
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Re: [OSM-talk] razed railways and other things that don't exist today

[Zeke Farwell]

On Tue, Oct 25, 2022 at 4:37 AM Frederik Ramm  wrote:

> If someone does a
> lot of good work for OSM otherwise and would really like to record an
> ancient former railroad that ran through where their house now sits - I
> shrug and let them do it. Only if someone starts to make it their
> mission to map every ancient railroad in the country and/or create
> relations so that you can see where trains used to ride in 1848 is when
> I'll ask them to stop and find a better place for it.
>

This does seem to be the mission of not just one mapper but quite a few
railway mappers.  They are trying to maintain a historical network of
railways for display on openrailwaymap.org and they like it to be a
connected network without gaps.  I can understand this desire, but it leads
to conflicts when, for example, a huge 8 lane highway has been built across
a section of razed railway.  One mapper will say "well clearly there can't
be any evidence of the razed railway left when the highway has been built
over it", and so will cut out the section of former railway where the
highway is.  This leaves the sections of razed railway on either side where
there probably still is some visible evidence that a railway used to
exist.  Those sections seem perfectly appropriate to keep.  The railway
mappers will then get very angry that this section was deleted because now
there is a gap in the (former) rail network.  This gap exists on the
ground, so mapping it as such seems entirely appropriate to me.  However,
the rail mappers argue that existence of a visible razed railway on either
side of the highway is enough evidence for the razed railway to also be
mapped across where there is now highway.  I've also seen it argued that
unless you can 100% prove that there *aren't any* traces of a razed railway
then it should be assumed that there are traces and the razed railway
should not be deleted.  For these railway mappers, this includes traces
that are now buried under new construction or underwater in a reservoir.
Clearly this is too high a burden of proof, and is not a standard we apply
to any other feature type.

I understand the desire to have a well connected network map of former
railways, but this comes into direct conflict with OSM's primary purpose of
mapping the world as it is today.

--
Zeke
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Re: [OSM-talk] razed railways and other things that don't exist today

[Dave F via talk]

On 25/10/2022 08:42, Warin wrote:


If OSM is about mapping what exists today .. why have the tags that 
mean there is nothing left of it?


The main OSM website/database shouldn't. it is for *current* data.

"OpenStreetMap is a place for mapping things that are both /real and 
current/"


https://www.openstreetmap.org/welcome

https://www.openhistoricalmap.org was design specifically for the 
purpose of representing old data.

I'd be happy for a mass transfer to it of out of date data.

The question with ephemeral data is, at what point in time do you 
refrain from adding info?
 I live in a historical Roman city. It would be clogged up with old 
infrastructure if everything was added.


Cheers
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Re: [OSM-talk] razed railways and other things that don't exist today

[Marc_marc]

Hello,

Le 25.10.22 à 09:42, Warin a écrit :

why have the tags that mean there is nothing left of it?


I'm using from time to time as a QA-tag to avoid that a mapper
add it back (and in fact, I don't care, for osm, if it's demolished, 
removed or destroyed, because if you weren't there the day it happened, 
you don't know anything about it, and what matters to osm is that

it's gone, that's why I just was:

however, i hear the argument that a demolished railway still has
a presence on site because of the civil engineering work it required.
it is also regularly reused to make pedestrian/bicycle greenways

it would be more accurate to map today's reality: this way has a 
terracing. good luck convincing those who fill this in osm :)


when to migrate the data to ohm, I am convinced.
however, having tested it this month, it's horribly non-ergonomic
and I don't believe for a moment that it's within the reach of
an iD contributor nor of an average contributor with josm,
unless a plugin exists, which I haven't seen

Regards,
Marc



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Re: [OSM-talk] razed railways and other things that don't exist today

[stevea]

As usual (nearly all of the time!), I appreciate and agree with your 
well-stated clarifications, Frederik!

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Re: [OSM-talk] razed railways and other things that don't exist today

[Frederik Ramm]

Hi,

you are correct in all aspects, however in the spirit of friendly 
collaboration I would say that a limited amount of 
stuff-that-should-not-be-in-OSM can be *tolerated*. If someone does a 
lot of good work for OSM otherwise and would really like to record an 
ancient former railroad that ran through where their house now sits - I 
shrug and let them do it. Only if someone starts to make it their 
mission to map every ancient railroad in the country and/or create 
relations so that you can see where trains used to ride in 1848 is when 
I'll ask them to stop and find a better place for it.


In a non-railway context, the various "this does not exist any more" 
prefixes can have value if the object in question is still visible on 
aerial imagery - otherwise, if you simply delete the thing from OSM, 
someone else will draw it back in.


The wiki should definitely say that all these tags are meant for special 
situations and the existence of these tags is not a reason/excuse to map 
every vanished object there is.


I would stress "not adding more of this" over "removing the stuff that 
already is in OSM" though. I don't want a horde of self-appointed 
cleaners running through OSM "because the wiki says so".


Bye
Frederik

--
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Re: [OSM-talk] razed railways and other things that don't exist today

[stevea]

On Oct 25, 2022, at 12:42 AM, Warin <61sundow...@gmail.com> wrote:
a
> Question:
about mapping of old railway infrastructure.

Without "meaning to be mean," I say "oh, no, not again!"  I say it like that 
because OSM has had this discussion many, many times.

I'll be relatively brief here and have at it with a short version, one more 
time.  OSM maps old railway infrastructure because it has very long-lasting 
effects on the land, affecting landuse, transportation patterns and more for 
decades, sometimes for centuries.  OSM (and OHM, OpenHistoricalMap, considered 
by some a "sibling project" of OSM) map(s) these, and OSM documents [1] (even 
with several pictures) that we do, saying "mapping such features is acceptable 
where some (of the infrastructure) remains."  Yes, there remains some 
controversy, the wiki goes to some length to explain what this is, what is a 
borderline case, etc.  But this is a topic which has been thoroughly discussed, 
even as it remains being discussed to this day.

Regarding other things which "don't exist today" which are NOT railways, well, 
those are a separate topic (from railways).

There:  "I didn't fix it..." but I hope that helps.

[1] 
https://wiki.osm.org/wiki/Demolished_Railway#What_is_sufficient_to_map_a_former_railway
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[OSM-talk] razed railways and other things that don't exist today

[Warin]

Hi,

Question:

If OSM is about mapping what exists today .. why have the tags that mean 
there is nothing left of it?



demolished:*=*
    Not existing anymore because of active removal
 removed:*=*
    Not existing anymore because of active removal (possible duplicate 
of demolished:*=*)

razed:*=*
    Not existing anymore because of active removal (duplicate of 
removed:*=*, possible duplicate of demolished:*=*)

destroyed:*=*
   Destroyed by an event other than active demolition

I think these tags would be of use in Open Historic Map (OHM) and that 
is possibly why they are in the OSM wiki?


Possibly the OSM wiki should recommend that the data with these tags be 
moved to OHM?



The argument for mapping these things from the 'old railway' people is that;

1) it does not render on the 'standard map' so it is not a problem.

2) it is used by Open Railway Maps (ORM)


My contention is;

1a) This is a problem when people try to map new things, the old things 
lead to mapping things that never existed like railway=crossing where a 
new footway/highway is also mapped over a now non existent railway line.


1b) People mapping new things may not see the old stuff on the new 
imagery .. and simply delete it, leading to edit wars.


1c) People map things like an old embankment for old railway lines .. 
right through existing roads


3) Old data should be mapped into OHM so it can be preserved .. together 
with the start and stop dates .. these 2 tags are fairly well ignored in 
OSM.


2) ORM should take current data from OSM and old data from OHM. This 
would add the start/end dates that could be used in ORM to select the 
time period. Thus those only interested in the present could have that, 
and those interested in some past date could have that.





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