[talk-au] sac_scale [Was: Deletion of walking tracks/paths]

[Andrew Harvey]

On Tue, 25 Jan 2022 at 18:32, Tom Brennan <website at ozultimate.com> wrote:

> On a related (track-y), but slightly tangential note...
>
> Is there any consensus on the use of sac_scale as the measure for trail
> difficulty in an Australian context?
>
> Personally, I hate the idea, because:
> - Australia has little in the way of real mountains
> - the values bear no relevance to Australian conditions
> - we're tagging for the renderer
>
> However, I hate the idea *more* of having no trail difficulty measure,
> and for better or worse:
> - this one exists
> - it's widely used, and rendered
>

Branching out to a new thread, you've summed it up perfectly.

If you have better ideas the beauty of OSM is you can tag both, so keep
using sac_scale for it's wide support but have a new tag better suited to
Australia which data consumers can start opting into.

As a rule of thumb, anything that requires using your hands I tag
sac_scale=demanding_mountain_hiking, anything that has fall hazards or
exposed areas on the trail but don't need hands sac_scale=mountain_hiking,
and anything else that you'd generally consider bushwalking (uneven
surface) sac_scale=hiking.

If I were to design the ideal tag for Australia, it would be something like:

technicality=0-3

0. Well formed, even surface (could almost walk it blindfolded).
1. Uneven surface, trip hazards from rocks, tree roots etc.
2. Large steps, long steps, may be slippery (wet, mossy or loose surface),
likely need to use hands for balance, low or tight sections that you need
to crouch
3. Short sections where you're almost pulling your whole body weight with
your arms (with or without a hand rope). Highest level short of proper rock
climbing.

by usual footwear people would wear:

0. thongs
1. joggers
2. hiking shoes
3. hiking shoes

by baby carrier accessibility:

0. okay for baby/child carriers
1. okay for baby/child carriers
2. using a baby/child carrier may not be viable
3. definitely can't use a baby/child carrier

sac_scale mixes in navigation skill needed, steepness, fall hazard, trail
markings, snow/glaciers, equipment like ice axes, whereas my scheme here is
more evaluating mobility.

We have tags for rungs, ladders, trail_visibility and route markings
(trailblazes) already.

In the Australian context there's also probably remoteness measure, but
these would be too subjective to tag on individual ways and probably could
simply be a function of distance to nearest facilities.

0. urban bushwalks
1. not too remote, mostly day walks
2. remote or multiday walks
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