Austria has a three point hiking scale: easy, moderate, hard. I observe the same in many portals: AllTrails, Komoot, OutdoorActive, e.g.
In essence, the SAC Hiking Scale has 1, 1+, 2-, 2, 2+, 3-, 3, 3+, 4-, 4, 4+, 5-, 5, 5+, 6-, 6 – no idea if there is 1- or 6+ I am too lazy to count how many points there are.
The Austrian scale recently got a pseudo fourth point: Alpine Route. This is for easy pathless scrambles. Not for hiking paths. Maintainers are in process of swapping guideposts in places where targets only reachable through such were marked simply as “hard”. Will take years. There is no scale for those routes.
GaiaGPS in the US uses color to show access (foot, foot and horse, foot and bicycle, etc). Caltopo lets you tap on a trail and a drawer on the side shows all the metadata for it.
I thought this too. If a tag is useless because it isn’t displayed directly then we should get rid of surface, smoothness, informal, operator, etc.
It’s developed for the Swiss Alps. 99% of the values are for the first three in the scale, with the vast majority (around 85%, I forget exactly). T1 and T2. It’s very strange marking up a trail in the desert as “mountain hiking” and there’s a lot of confusion around it. I’ll see T1 trails above treeline marked up as T4 in North America because it’s “alpine”.
There’s a lot of ambiguity in past posts in the forum here - a T1 difficulty trail has T4-T5 level exposure so someone wants to tag it as T2. Mixing those things up is a mess. I have plenty of times where I’m on less technical but more exposed terrain, or more technical but less exposed terrain.
This is used in North America, though it tends to vary widely by region and be graded on a sort of local subjective scale relative to things around it. Interestingly I’ve come across people in AllTrails complaining about a short level hike marked as “easy” because it had roots in the trail that were ~T2 so it should have been “moderate”.
As someone who spends a LOT of time with slope shading (I do a lot of what would be similar to the Austrian Alpine Routes). I’ll say it isn’t useful at all for actual exposure risk, it’s not granular enough.
These two photos are from this area of trail. The one with less direct exposure actually looks worse on Topo. This is with the updated high resolution US slope angle shading.
The following XC “route” has more purple shaded terrain (~double the height) using old slope angle shading but it was ledgey enough that I was able to come down it with a T3 / YDS 2 technique and minimal “short fall” exposure. Going up was T4 / YDS 3 and that’s how I’d describe it.
In terms of how to display it, icons on the trail would work. Direct exposure could be a diamond with a vertical line in it, indirect exposure could be a square with a line that is initially more horizontal that then goes vertical.
I’m not opposed to using hazards for this, but natural=cliff doesn’t indicate if the trail is 3cm or 3m from a cliff edge (likewise ridge or arete). The closest value on hazard=* which exists is falling rocks which isn’t appropriate. It’d be better than the current use case where it’s impossible to extrapolate exposure since it is mixed in with technique.
I think there’s a few different cases that would need to be addressed:
A brief moment of exposure on a trail seems totally appropriate for this (and should be used even if there is a separate exposure key for ways/paths). I think in this case being able to differentiate between direct and indirect exposure would be useful, so that would be two values at least. Short falls could probably be ignored in the sense of being called out on topo vs being metadata for a path.
For longer stretches of exposure, how would hazards work? Would there be two tags that act as bookends (start/stop, open/close) or would it just be a hazard tag every 5-10m.
Knowing that 200m of trail is exposed is different than a 5m section. Having two hazard tags 200m apart could look like it’s just two brief spots but having 20-40 hazard tags seems messy.
It is funny that the tags are from a Swiss scale and the colours are from an Austrian scale. Is there any renderer that uses the Swiss colours? [Apart from the JOSM SAC mapcss plugin; in the lower grades, that is.]
PS: In the 2023 SAC Hiking Scale, SAC scale and SWW colour are no longer identical. I made some changes to the Wiki, somebody even noticed
My main problem with this proposal is that it is for no good reason activity specific, why can’t it just be “exposure” and not imply that hiking exposure is different from the same on a via ferrata or on a mountain bike, or whatever.
Why not add a heading Hiking related hazards to the Key:hazard wiki and create hazard=exposure, etc.?
To the wiki for sac_scale we could then add that it is assumed that hiking risks increase with increasing sac_scale, and that for path sections that have an unexpectedly high risk that is not evident from other information on the map, a tag from the hazard key can be added. It is then up to map renderers to decide how to display that information (probably one “danger” symbol if the section is short, and one at each end if the section is long).
Someone from Australia came in and was expecting exposure to be exposure to the elements (so lack of tree shade etc). It’s a somewhat mountaineery term so fall_risk seemed more straightforward as a suffix and moving the prefix to path solves this issue as mountain bikers etc face the same exposure.
I’ve found on and off talk about having foot/trail specific hazards for years in various places in OSM. If this thread pushes that into action it’ll have been a success (and it helped me think out how to describe off-trail routes outside the scope of OSM).
Here’s another example where looking at topo lines doesn’t give you an accurate idea of exposure. Gotta love how the river flows up and then back down a 100 foot saddle. It’s not uncommon for opentopo in the southwest to be a bit off (though not as badly as this).
topo and old slope angle shading (derived from the same old shuttle data)
topo and new slope angle shading (I corrected some ways in this area so the trail shows going through here now, there’s some that are clearly just a few nodes with staight lines going to them but I haven’t been there to verify):
I am too lazy to count how many points there are.
