[Tagging] Feature Proposal - RFC - highway=scramble

[Georg]

Dear Peter and all others,

I gained the impression you do not find consent just because you are
using different definitions for the same thing: SAC T4-T6. 🙈

Peter wrote Thu Sep 15 2022 17:30:25 GMT+0200

Peter
>>>         Which combination(s) of highway values, sac scale values and
>>>         hazard values would exclusively represent a scramble

Janko
>>     Any of the three combinations:
>>     highway=path + sac_scale=alpine_hiking
>>     highway=path + sac_scale=demanding_alpine_hiking
>>     highway=path + sac_scale=difficult_alpine_hiking

Peter
> So, a selection of sac_scale values may or may not include scramble
> sections, beside other posible obstacles/hazards/challenges. If you
> specifically want to know where the scramble sections are, the sac_scale
> doesn't tell you, correct?

Yes and no 🤪

Janko's and Yves' answer that T4-T6 _require_ hands is correct when
using the _German_ definition
https://wiki.openstreetmap.org/wiki/DE:Key:sac_scale

In contrast, the _English_ definition
https://wiki.openstreetmap.org/wiki/Key:sac_scale did tell until now
that hands are optional for T4+T5 and only mandatory for T6 – so it
supported Peter's view – which was not consistent with the original
definition of SAC telling "you’ll need to
use your hands" already for T4, see
https://www.sac-cas.ch/fileadmin/Ausbildung_und_Wissen/Sicher_unterwegs/Sicher_unterwegs_Wandern/2020_Berg_Alpinwanderskala_EN.pdf
  I just updated the EN wiki page to match with SAC's definition.


To extend the answer on Peters original question:

Based on SAC's definition, each path of grade SAC T4 and above is a
scramble, because definition of T4-T6 is that at some point, one needs
the hands to go further.

Climbing, by all definitions I saw, needs hands.
https://theuiaa.org/mountaineering/uiaa-grades-for-rock-climbing/ even
mentions the word "scramble". So if someone does not want to use hands,
exclude any object tagged as sport=climbing – and please note that UIAA
grade I and II is not only suitable for cliffs but also a hiking path of
SAC T5 or T6, so it is relevant on Peter's question.

For https://wiki.openstreetmap.org/wiki/Key:hazard it's a little less
clear, as there are not yet many agreed values for the kind of physical
objects we are talking about. Probably relevant values found via taginfo
are hazard=falling and =steep and =slip_danger and =steep_slope.

Considering what surprisingly high steps specialized off-road vehicles
can manage, the two worst values of
https://wiki.openstreetmap.org/wiki/Key:smoothness will likely require
pedestrians to use hands.

Yves did trow in
https://wiki.openstreetmap.org/wiki/Key:trail_visibility at Thu Sep 15
2022 17:06:25 GMT+0200. I am not creative enough to deduct from
visibility whether hands need to be used, but I still list it as others
might have an idea 🙂



While above keys/values enforce use of hands and thus answer your
question, these are not best to satisfy your expressed interest: To
avoid scramble sections. Why not?
1) Some ways might simply not yet carry above mentioned tagging
    but wait for someone adding it.
2) There may exist some more keys/values not yet mentioned here.

To more reliably avoid scrambles, you need to approach from the other
side: Choose ways tagged as SAC T2 and T1 because they must not be a
scramble, by their definition, and the relevant information is certainly
existing in OSM DB. Only remaining bigger risk is that map and territory
are not matching.

Best regards,
Georg