Re: [Tagging] 'Unknown' value.

[Andy Townsend]

On 16/03/2018 21:46, marc marc wrote:

SomeonElse write me today because since access=unknown could have a
hidden meaning (= for access key, the mapper doesn't know if access is
allowed and wants to make it known that it's complicated)


What I actually said was on 
https://www.openstreetmap.org/changeset/55979006 , which referred to 
https://wiki.openstreetmap.org/wiki/Automated_edits/marc__marc#purge_related_to_wheelchair.3Dunknown 
, which when I wrote that comment said 
https://wiki.openstreetmap.org/w/index.php?title=Automated_edits/marc_marc=1570486 
"It was a bug  on 
wheelpmap.org that added the unknown status when a user did not fill in 
all the fields or change the previous value".


It's now been changed to say "Without a wheelchair or toilets:wheelchair 
tag, accessibility of a poi or toilets of a poi is already unknown..." 
(i.e. to reflect the change that was actually made).


Best Regards,
Andy


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Re: [Tagging] 'Unknown' value.

[Kevin Kenny]

On Fri, Mar 16, 2018 at 5:46 PM, marc marc  wrote:
> SomeonElse write me today because since access=unknown could have a
> hidden meaning (= for access key, the mapper doesn't know if access is
> allowed and wants to make it known that it's complicated), he finds that
> this cleaning should be reverteded, at least for cases that don't fit in
> the cases previously listed in the discussions (application bug, import
> of bad qualities).

'wheelchair' is quite possibly a different situation. Is 'wheelchair=yes'
the default assumption anywhere?


For the access and transport mode tags, the routing engines take
'yes' as the default for a good many types of ways; 'highway=path'
or 'highway=track' default to 'foot=yes'.

Where I don't know for sure that foot traffic is lawful, I don't want to
tag 'foot=no', (likewise, bicycle, ski, motor vehicle, etc.). And the
default for the type of the way is 'yes', so I need a third value. That
seems to be what 'unknown' is for.

For that reason, there are some snowmobile routes that I've tagged
'highway=track access=unknown snowmobile=yes' in that I know
they're lawful for snowmobilists (who pay a special tax for the
privilege, assessed on the registration of their sleds) but don't
know the policy for other modes.

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Re: [Tagging] 'Unknown' value.

[marc marc]

Hello,

 > wheelchair=unknown mostly in Iraq and Saudi Arabia (also from older 
imports)

Many months before this thread, talk for an automated edit was started 
to cleanup 15k+ objets with this value (most due to a wheelmap bug and 
bad undocumented import, but not only).
As the wiki said, for wheelchair, without any tag, the status is already 
unknown and it's requested on the wiki to NOT add unkwnown value.
the discussion was made on the 8 most affected or adapted places,
no one objected or expressed any use for this (wheelchair access) key.
which is why the cleaning was done.
I was also advised to do the cleaning for the remain objets worlwide 
because some countries had less than 50 objects concerned and it 
therefore makes no sense to continue one announcement per country.
We also talk it in this thread, nobody found a usecase for 
wheelchair=unknown.

SomeonElse write me today because since access=unknown could have a 
hidden meaning (= for access key, the mapper doesn't know if access is 
allowed and wants to make it known that it's complicated), he finds that 
this cleaning should be reverteded, at least for cases that don't fit in 
the cases previously listed in the discussions (application bug, import 
of bad qualities).
It is important to specify that the wiki clearly specifies the criteria 
to have wheelchair=yes limited or no.
A state unknown to someone therefore just means that the person who made 
the addition didn't bother to look at the criteria or didn't take them 
into account or found an ambiguity on the wiki that it would be helpful 
to talk about.

So my question is:
Should you modify the wiki to say that if you don't know if a place is 
accessible for a wheelchair user, you still need to add an unknown tag ? 
if the situation is really ambiguous, isn't wheelchair:description 
enough ? or note ? or fixme ? or no wheelchair tag at all, another 
mapper 'll check it next time.
Or should all applications take this unknown value into account? I think 
for example of the multiple tools that highlight the missing values for 
a given subject and which would therefore need to consider unknown as 
equivalent to absent. but also "maybe" "idontknown" "idontcare" values 
or any invention of this kind whose interest I hardly understand.

My opinion is obviously leaning to add useful tags. so if someone is 
unable to tag wheelchair status for a POI, don't add any wheelchair tag 
or adding WHY in wheelchair:description or note seems more suitable to 
me than inventing new unused value that provides no explanation for the 
problem. and therefore are unusable except for the mapper that create it

[1] 
https://wiki.openstreetmap.org/wiki/Automated_edits/marc_marc#purge_related_to_wheelchair.3Dunknown
[2] https://wiki.openstreetmap.org/wiki/Key:toilets:wheelchair

Regards,
Marc
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Re: [Tagging] 'Unknown' value.

[Kevin Kenny]

On Mon, Feb 5, 2018 at 4:28 PM, Andy Townsend  wrote:
> I use fixmes a lot (I even wrote something to extract them from OSM for
> survey - https://github.com/SomeoneElseOSM/Notes01 ).  Where I've used e.g.
> foot=unknown it usually means "I've been there, I don't know what the access
> rights are, and there's really nothing that I can suggest surveying to find
> out what they are".

'access=unknown' (and the corresponding tags for transportation modes)
really seem to be a special case and have been called out on the Wiki.
I have at least contemplated using it for similar reasons to Andy's.
(I'd actually have to check to see if I've done it.)

An example in my area is the snowmobile trails. The numbered corridor
and secondary routes, I know, are open to all snowmobilists who have
paid the tax. These trails, in summer, are often at least physically usable
as hiking and ATV trails. Whether they're lawful depends on the
landowner - the snowmobile easement (for which the landowner is paid)
doesn't necessarily extend to hiking, mountain biking or ATV riding.
I know that blazed trails that appear in a guidebook have at least
permission, if not an easement, negotiated by the hiking clubs, and
that posted ones are off limits. But there are a lot of landowners who
don't trouble to post. Since, if they haven't posted, all they really
can do if they catch me trespassing is ask me to leave, I feel
comfortable hiking many of these trails, but I'm not about to mark them
"foot=yes" or "foot=permissive" without stronger evidence, and unless
I happen to encounter one of the owners, I really have little way to
acquire the information.

(Even stranger are the cases where there are public
rights-of-way across posted lands that the landowners would prefer
to have forgotten. They're 'foot=designated' when the clubs encourage
hikers to ignore the posted warnings and use the old carriage
roads openly and notoriously, since in many cases they are and
remain public highways.)

Few areas are as messy as mine, though.

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Re: [Tagging] 'Unknown' value.

[Andy Townsend]

On 05/02/2018 16:46, OSMDoudou wrote:

I'd rather use fixme and note tags instead of encoding uncodified information 
in well-established tags.


I use fixmes a lot (I even wrote something to extract them from OSM for 
survey - https://github.com/SomeoneElseOSM/Notes01 ).  Where I've used 
e.g. foot=unknown it usually means "I've been there, I don't know what 
the access rights are, and there's really nothing that I can suggest 
surveying to find out what they are".


Cheers,
Andy


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Re: [Tagging] 'Unknown' value.

[OSMDoudou]

You have a point… :-)

The wiki already presents the idea that unknown means "unclear". [2]

Taginfo tells access=unknown has 20 thousand occurrences (i.e. 0.30% and 
ranking at the 11th position), which makes it not so unusual. [3]

The discussion here shows the value of "unknown" raises confusion, but 
admittedly if it was "unknown", "unclear", "uncertain", "difficult-to-tell" or 
whatever, it will always come down to awareness and getting used to the concept.

[2] https://wiki.openstreetmap.org/wiki/Key:access
[3] https://taginfo.openstreetmap.org/keys/access#values 



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Re: [Tagging] 'Unknown' value.

[Adam Snape]

Hi,

Is 'unknown' really such an unusual and undesirable as an access tag? I
thought it was long-established, if not especially common. If the issue is
a lack of Wiki documentation that is easily solved.

I think that highway=footway foot=unknown adds a useful level of nuance.
For example a routing engine could choose to avoid such routes where it
would route over a footway by default. Of couse we could produce this
result by tagging foot=no, but if we don't know that pedestrians actually
aren't allowed that would be incorrectly tagging for the router.
foot=unknown could be considered an implicit fixme in the same way as
highway=road is, but also have teh benefit of being useable directly by
data consumers (if they chose to use it) unlike the free-form text
contained in notes and fixmes.

More generally, wherever an absence of a particular tag is taken to imply
something is or isn't present then a tag of something=unknown does have a
valid and worthwhile meaning distinct from no tag at all. .

Adam

On 5 February 2018 at 16:46, OSMDoudou <
19b350d2-b1b3-4edb-ad96-288ea1238...@gmx.com> wrote:

> I'd rather use fixme and note tags instead of encoding uncodified
> information in well-established tags.
>
> The wiki page [1] explains a bit the difference: "The fixme key allows
> contributors to mark objects and places that need further attention. These
> can be in the form of a "note to self" or request for additional mapping
> resources. Its distinction from note=* is that fixme is only to express
> that the mapper thinks there is an error, while note might be information
> to other mappers."
>
> If it's reasonable to think tagging can be improved (e.g. initial tagging
> was a bit rushed and better tagging is expected based on site survey or
> imagery), than a fixme note looks suitable.
>
> In the case you describe ("nothing suggesting that further survey will
> reveal what the legal situation is"), a note looks suitable to document
> there was a site survey and explain why "it was obvious that it was not
> obvious" (that is to say: explaining the elements causing your perplexity
> conveys much richer information than tagging "unknown").
>
> And you could also start a discussion on the mailing list and link to it
> from the note, so other mappers are aware of the discussion and can
> contribute.
>
> [1] https://wiki.openstreetmap.org/wiki/Key:fixme
>
>
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Re: [Tagging] 'Unknown' value.

[OSMDoudou]

I'd rather use fixme and note tags instead of encoding uncodified information 
in well-established tags.

The wiki page [1] explains a bit the difference: "The fixme key allows 
contributors to mark objects and places that need further attention. These can 
be in the form of a "note to self" or request for additional mapping resources. 
Its distinction from note=* is that fixme is only to express that the mapper 
thinks there is an error, while note might be information to other mappers."

If it's reasonable to think tagging can be improved (e.g. initial tagging was a 
bit rushed and better tagging is expected based on site survey or imagery), 
than a fixme note looks suitable.

In the case you describe ("nothing suggesting that further survey will reveal 
what the legal situation is"), a note looks suitable to document there was a 
site survey and explain why "it was obvious that it was not obvious" (that is 
to say: explaining the elements causing your perplexity conveys much richer 
information than tagging "unknown").

And you could also start a discussion on the mailing list and link to it from 
the note, so other mappers are aware of the discussion and can contribute.

[1] https://wiki.openstreetmap.org/wiki/Key:fixme 


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Re: [Tagging] 'Unknown' value.

[OSMDoudou]

> Like with any tag value, if data consumers don't undestand it they can just 
> ignore it.

One of the data consumer is human. And humans are confused when something hold 
unexpected value. :-)


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Re: [Tagging] 'Unknown' value.

[Rafael Avila Coya]

Hi all:

I was the one who organized the import of 14,000+ places nodes in 
Liberia back in September 2014.


The idea of giving place=unknown (together with a fixme=* tag) to places 
that were not possible to determine its value was proposed during the 
discussion in the imports list [1] [2].


place=yes was also proposed, and now I guess it would be better than 
place=unknown


Back in 2014 many areas of Liberia lacked hires imagery. Now we have 
imagery for all the country.


2 days ago, the number of nodes with place=unknown was 977 (so 7% of all 
the imported nodes). In a short time I retagged more than 100 (they are 
861 nodes with place=unknown left (6%)), a quite easy task.


So I strongly oppose to the removal of these nodes, that could be 
retagged quite easily in a short time.


As for the nodes that cannot be retagged, we could change them to place=yes.

Cheers,

Rafael.

[1] 
https://lists.openstreetmap.org/pipermail/imports/2014-September/003419.html
[2] 
https://lists.openstreetmap.org/pipermail/imports/2014-September/003421.html


On 03/02/18 23:16, Nelson A. de Oliveira wrote:

On Sat, Feb 3, 2018 at 4:18 PM, Dave F  wrote:

I recently seen a variety of keys being given the value of 'unknown'.
I'm struggling to see its purpose. It confirms nothing & adds no value to
the database. Am I missing something?


You are right.

It's interesting if you take a look at some values.

maxspeed=unknown basically happens only in the Netherlands, from the
same author (it seems) who is mapping/importing railway data.

owner=UNKNOWN in California, USA, from an old buildings import

place=unknown in Africa (due to this import
https://wiki.openstreetmap.org/wiki/Import_Liberia_UNMIL_Places#Tagging_Plans)

bench=unknown are mostly in Italy (from some possible bus stops/routes import)

foot=unknown in England
naptan:Landmark=Unknown also in England (both foot and naptan:Landmark
look that are old data)

wheelchair=unknown mostly in Iraq and Saudi Arabia (also from older imports)

By taking a quick look at them, most seem to be from imports, created
by the same mappers or old data.

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Re: [Tagging] 'Unknown' value.

[Warin]

On 05-Feb-18 03:30 AM, Martin Koppenhoefer wrote:


sent from a phone


On 4. Feb 2018, at 12:44, OSMDoudou 
<19b350d2-b1b3-4edb-ad96-288ea1238...@gmx.com> wrote:

If your analysis shows these tags don't add value (this is to say: don't make a 
gigantic update on places you haven't reviewed), you better remove them 
(possibly with a comment on the changeset explaining you're removing tags which 
don't make sense).


I don’t think they should be batch removed, I see them as a kind of fixme tag, 
which might have been applied because the mapper thought an important property 
needs resurvey, especially barrier=unknown or access=unknown on barriers


If the tags were applied by an import (or batch) then I see no reason not to 
remove them as a batch.

If part of an import they might ... but only might ... not have that 
information in the import.

That would have been better added as a note saying import x does not have 
information on x, y, z for this feature.

But *=unknown is very unhelpful.


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Re: [Tagging] 'Unknown' value.

[Fernando Trebien]

Maybe they should be converted into a fixme=* value then, such as
fixme="unknown maxspeed;unknown foot access;unknown wheelchair
accessibility".

Though I've always assumed that an absent tag means its value is
unknown, so foot=unknown and no foot=* whatsoever would mean the exact
same thing. Some would disagree though. [1]

[1] https://lists.openstreetmap.org/pipermail/tagging/2018-January/034546.html

On Sun, Feb 4, 2018 at 2:30 PM, Martin Koppenhoefer
 wrote:
>
>
> sent from a phone
>
>> On 4. Feb 2018, at 12:44, OSMDoudou 
>> <19b350d2-b1b3-4edb-ad96-288ea1238...@gmx.com> wrote:
>>
>> If your analysis shows these tags don't add value (this is to say: don't 
>> make a gigantic update on places you haven't reviewed), you better remove 
>> them (possibly with a comment on the changeset explaining you're removing 
>> tags which don't make sense).
>
>
> I don’t think they should be batch removed, I see them as a kind of fixme 
> tag, which might have been applied because the mapper thought an important 
> property needs resurvey, especially barrier=unknown or access=unknown on 
> barriers may indicate a high probability for access restrictions (e.g. you 
> can see in the aerial imagery the shadow of some kind of barrier but don’t 
> know more). I would be in favor of batch removing those unknown that have 
> been batch introduced but not those inserted individually
>
>
> cheers,
> Martin
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-- 
Fernando Trebien
+55 (51) 9962-5409

"Nullius in verba."

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Re: [Tagging] 'Unknown' value.

[Andy Townsend]

On 03/02/2018 22:16, Nelson A. de Oliveira wrote:

foot=unknown in England


I've added a few of those - mostly they're places where there is 
physical access, but it's really not clear what the access rights (if 
any) are.  There's no signage suggesting legal access, no infrastructure 
suggesting planned or tolerated access, and most importantly nothing 
suggesting that further survey will reveal what the legal situation is - 
what normally happens is that some time later (months or years) it gets 
signed as either legally accessible or inaccessible.


Like with any tag value, if data consumers don't undestand it they can 
just ignore it.


Best Regards,
Andy


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Re: [Tagging] 'Unknown' value.

[Martin Koppenhoefer]

sent from a phone

> On 4. Feb 2018, at 12:44, OSMDoudou 
> <19b350d2-b1b3-4edb-ad96-288ea1238...@gmx.com> wrote:
> 
> If your analysis shows these tags don't add value (this is to say: don't make 
> a gigantic update on places you haven't reviewed), you better remove them 
> (possibly with a comment on the changeset explaining you're removing tags 
> which don't make sense).


I don’t think they should be batch removed, I see them as a kind of fixme tag, 
which might have been applied because the mapper thought an important property 
needs resurvey, especially barrier=unknown or access=unknown on barriers may 
indicate a high probability for access restrictions (e.g. you can see in the 
aerial imagery the shadow of some kind of barrier but don’t know more). I would 
be in favor of batch removing those unknown that have been batch introduced but 
not those inserted individually 


cheers,
Martin 
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Re: [Tagging] 'Unknown' value.

[OSMDoudou]

Others already gave possible causes, so I won't add or repeat.

It's pointless tagging and leaves us guessing whatever it could mean.

If your analysis shows these tags don't add value (this is to say: don't make a 
gigantic update on places you haven't reviewed), you better remove them 
(possibly with a comment on the changeset explaining you're removing tags which 
don't make sense).


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Re: [Tagging] 'Unknown' value.

[marc marc]

Hello,

Le 03. 02. 18 à 19:18, Dave F a écrit :
> I recently seen a variety of keys being given the value of 'unknown'.
> I'm struggling to see its purpose. It confirms nothing & adds no value 
> to the database. Am I missing something?

it's hard to explain without an example.

from my personal experience with the ongoing cleaning of 
toilets:wheelchair et wheelchair, there were 3 reasons :
- a bug in an editor that incorrectly filled in with a "default"
as value when the user did not fill in a value.
- an (old) import (without a doc or missing link to the doc)
that assigned default values (also I guess it happened when he
didn't have any data)
- when an editor proposes a few keys, somes mappers do not know what
to fill in and put "unknown" thinking that it is mandatory to fill
in all the fields to pass validate.

This obviously has no interest in any of the 3 situations (the bug of 
the first one has been fixed, the 2nd will soon be cleanup, the 3rd one 
is more complicated because it is necessary to "train" new users and/or 
improve the ergonomics of editors this can be seen for example with 
the access key where you can even see "no ski" on roads
of a city a thousand km away from the ski resorts.

if you see a recent case, it is interesting to find the cause
to inform the mapper and/or improve the ergonomics of the editor used.

Regards,
Marc
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Re: [Tagging] 'Unknown' value.

[Nelson A. de Oliveira]

On Sat, Feb 3, 2018 at 4:18 PM, Dave F  wrote:
> I recently seen a variety of keys being given the value of 'unknown'.
> I'm struggling to see its purpose. It confirms nothing & adds no value to
> the database. Am I missing something?

You are right.

It's interesting if you take a look at some values.

maxspeed=unknown basically happens only in the Netherlands, from the
same author (it seems) who is mapping/importing railway data.

owner=UNKNOWN in California, USA, from an old buildings import

place=unknown in Africa (due to this import
https://wiki.openstreetmap.org/wiki/Import_Liberia_UNMIL_Places#Tagging_Plans)

bench=unknown are mostly in Italy (from some possible bus stops/routes import)

foot=unknown in England
naptan:Landmark=Unknown also in England (both foot and naptan:Landmark
look that are old data)

wheelchair=unknown mostly in Iraq and Saudi Arabia (also from older imports)

By taking a quick look at them, most seem to be from imports, created
by the same mappers or old data.

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Re: [Tagging] 'Unknown' value.

[Matej Lieskovský]

(Without digging through the database) I suspect that might be caused
by the idea of default values... Imagine drawing a road. If you don't
tag it as 'oneway', it is assumed not to be a 'oneway'. If you
honestly don't know, you need to tag it with something like 'unknown'.
But that's just my guess - why not contact the author?

Matej

On 3 February 2018 at 19:18, Dave F  wrote:
> Hi
> I recently seen a variety of keys being given the value of 'unknown'.
> I'm struggling to see its purpose. It confirms nothing & adds no value to
> the database. Am I missing something?
>
> DaveF
>
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[Tagging] 'Unknown' value.

[Dave F]

Hi
I recently seen a variety of keys being given the value of 'unknown'.
I'm struggling to see its purpose. It confirms nothing & adds no value 
to the database. Am I missing something?


DaveF

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[Tagging] 'Unknown' value.

[Dave F]

Hi
I recently seen a variety of keys being given the value of 'unknown'.
I'm struggling to see its purpose. It confirms nothing & adds no value 
to the database. Am I missing something?


DaveF

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