[Tagging] cycleway:both=no in StreetComplete

Thu Jan 4 23:09:08 UTC 2018

On Thu, Jan 4, 2018 at 9:57 AM, Matej Lieskovský
<lieskovsky.matej at gmail.com> wrote:
> 1) If we try to add every possible tag to every element, the DB will be
> immense and the OWG will try to kill us. Imagine every road having access
> tags. Should roads have tunnel=no?

I will digress a bit, as I believe this should be a separate topic.

We could define a tag such as highway_defaults=yes to express that a
certain number of default values have been throughly verified by a
mapper, and assume that any difference from those defaults will be
mapped by adding extra tags. It could also be automatically inserted
by bots once all tags in the default tags set have been added.

So highway_defaults=yes could include things such as:
- oneway=no for all highway types except motorway and motorway_link,
for which oneway=yes
- cycleway=no (implying cycleway:left=no, cycleway:right=no and
cycleway:both=no) for all highway types
- surface=asphalt (and perhaps lit=yes) for highway=cycleway
- tunnel=no, bridge=no, lit=yes, embankment=no, cutting=no, ford=no,
ice_road=no for all highway types

And much more. In fact, the most common value (as reported by TagInfo
or as implied by experience) for every tag could be the default value
(subject to periodic review). A few ideas that come to my mind
immediately:
- access=* as defined in the Default table here:
https://wiki.openstreetmap.org/wiki/OSM_tags_for_routing/Access-Restrictions#Default
- shoulder=no, parking:lane:both=parallel, sidewalk=both,
tactile_paving=no, wheelchair=yes for local public urban highway types
(residential, living street)
- surface=asphalt, smoothness=excellent for non-local highway types
(unclassified, tertiary, secondary, primary, trunk, motorway)
- shoulder=yes, sidewalk=no for motorway and motorway_link and perhaps
trunk and trunk_link
- service=driveway for highway=service
- tracktype=grade3 for highway=track
- wall=no for buildings and landuse
- material=wood for power towers and power poles
- frequency=50 for power lines

We would also have to contact the developers of several important apps
to request support for such a tag. In the case of cycleways, that
would be Thunderforest / OpenCycleMap. For the other tags, ITO World
comes to my mind. And of course, StreetComplete too. And iD still
needs to warn the user about absent tags when combining ways. And we
have to update the wiki article of several tags to list their default
values. That's a ton of work, but if database efficiency and mapper
effort is a concern, maybe it's worth doing. (I honestly think it is,
but it requires more discussion and a proposal for voting.)

And also something similar could be done for other modes of
transportation, such as railway=* and waterway=*.

> 2) Data consumers will sometimes still need to guess the value, which means
> a default still needs to be known.

They already do, and especially those providing global services are
doing so incorrectly as none that I know of support definitions that
vary between countries, such as the differences in access=* defaults.
But I think global defaults would already mitigate a great part of the
problem.

> On 4 January 2018 at 02:22, Fernando Trebien <fernando.trebien at gmail.com>
> wrote:
>>
>> Tag absence has never been defined clearly in OSM. Some think of it as
>> meaning "the tag has the default value," others think "the value of the tag
>> is still unknown," which seems to be the most common understanding (that's
>> why noname=* exists).
>>
>> I always add tags in their default value to express that the value is
>> known and has been surveyed, cycleways included. (though in the case of
>> cycleways I usually only add them around existing cycleways to avoid
>> confusion and to prevent mappers - especially those using iD - from
>> combining sequential ways without getting a warning)
>>
>> Em 25 de dez de 2017 23:34, "Dave Swarthout" <daveswarthout at gmail.com>
>> escreveu:
>>>
>>> This sounds similar to those that suggested adding oneway=no to all
>>> streets that are not explicitly tagged as oneway=yes. All roads without
>>> cycleways could conceivably be tagged this way.
>>> Unless there is some cause for such a tag, for example, noting that a
>>> cycleway once existed here but is no longer present, this tag is totally
>>> unnecessary and adds needless data to OSM.
>>>
>>> On Tue, Dec 26, 2017 at 6:50 AM, marc marc <marc_marc_irc at hotmail.com>
>>> wrote:
>>>>
>>>> Hello,
>>>>
>>>> Le 26. 12. 17 à 00:22, Dave F a écrit :
>>>>
>>>> > There's been quite a few recent additions of 'cycleway:both=no' being
>>>> > added by users of StreetComplete.
>>>> >
>>>> > http://www.openstreetmap.org/way/8609990
>>>> >
>>>> > There's no mention of this tag on the wiki & to me appears a bit
>>>> > ambiguous. Most (all?) are the sole cycle tag on the entity. Both=no
>>>> > suggests that a cycleway could exist in one direction.
>>>>
>>>> I agree that cycleway:both=no is not a good tag.
>>>> cycleway=no is better.
>>>>
>>>> > What is the reason the developers aren't using the established tagging
>>>> > scheme:
>>>> > https://wiki.openstreetmap.org/wiki/Key:cycleway
>>>>
>>>> ask the dev :)
>>>>
>>>> > Note under 'cycleway=no' as a tag of "dubious usefulness".
>>>>
>>>> I could help to see what road have been surveyed and somebody see that
>>>> this road doesn't have a cycleway. Put in urban area, it's a (minor)
>>>> added value. Without a cycleway tag, the cycleway is unknown.
>>>>
>>>> > This email has been checked for viruses by Avast antivirus software.
>>>>
>>>> it's also a dubious usefulness :)
>>>>
>>>> Regards,
>>>> Marc
>>>> _______________________________________________
>>>> Tagging mailing list
>>>> Tagging at openstreetmap.org
>>>> https://lists.openstreetmap.org/listinfo/tagging
>>>
>>>
>>>
>>>
>>> --
>>> Dave Swarthout
>>> Homer, Alaska
>>> Chiang Mai, Thailand
>>> Travel Blog at http://dswarthout.blogspot.com
>>>
>>> _______________________________________________
>>> Tagging mailing list
>>> Tagging at openstreetmap.org
>>> https://lists.openstreetmap.org/listinfo/tagging
>>>
>>
>> _______________________________________________
>> Tagging mailing list
>> Tagging at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/tagging
>>
>
>
> _______________________________________________
> Tagging mailing list
> Tagging at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/tagging
>

-- 
Fernando Trebien
+55 (51) 9962-5409

"Nullius in verba."