RfC: Highway=Scramble

I think I would put highway=via_ferratta on this, but if highway=scramble was adopted, maybe that would be closer. If you have to use hands, than it can’t be just a path IMHO. In any case, safety_rope=yes should be there.

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I have difficulties to understand your comment :thinking:

  1. What do you mean by “no physical structure”? The majority of scrambles I have been doing are showing physical structures that make them as distinguishable from the surrounding as a usual highway=path in the mountains, like waymarks, holes in the vegetation for air-space required by a person and because the feet reduce/remove grass and low bushes, different texture of gravel or rock or soil, some have rungs others holds/steps hammered into the stone and others ropes, etc.
  2. What do you mean by “trail_visibility has a different meaning”? I’d map and expect exactly the same meaning for a scramble as for highway=path.

That’s one of several reason why I find highway=scramble inferior to the alternative highway=demanding_path + demanding_path=scramble (or other wording): The latter seems to allow an automated edit for a considerable share of ways, namely all SAC T4-T6, see this tagging mailing list post – we must of course discuss whether we want to do or not.

As such a user, I do explicitly not want my mapping efforts to be visible on all maps because that’s against the very basic idea of having multiple maps: specialization. For example, I wish wheelmap.org or OsmAnd in car driving profile will not show scrambles, while waymarkedtrails.org shall. This way, maps allow me to better focus and perceive more quickly what is relevant in a certain context :slightly_smiling_face:


I 100% agree.

I’m open to considering the idea of highway=demanding_path, but that would be a different, broader description than what @Hungerburg developed for highway=scramble. In your vote comment you say it is more verifiable and less subjective, but I do not see this. If I lived in a region where all hiking routes are given an official SAC scale rating by some authority then perhaps I would agree. Then I could simply verify if the rating was T4-T6 and tag highway=demanding_path. However this is not the case in my area of the world. There are no official ratings to verify against. So it would be a subjective assement on my part whether a given trail qualifies as “demanding” or not. On the other hand, I find highway=scramble intuitively verifiable even though it also is not free of subjectivity.


I do not want to speculate on the reasons, but the foot profile for OSMRF as applied on the OSM website certainly is one such app.

PS: Luckily, only few get into danger. In most cases, users just will turn around before they get into danger.

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Coming here late, but perhaps some thoughts that can be used moving forward.

Scramble can be used to describe anything from Class 2-4 in YDS so that’s a wide net. Having a highway=scramble lets me know that it’s not Class 1 or SAC 1-2, but I’m more concerned about whether there is fatal exposure and/or semi-technical sections than I am whether I have to use my hands every once in a while for balance. There is too large difference in technique from the low to high end IMO

A strict interpretation scramble as just “use of hands” opens up a lot of normal trails that overlap into YDS Class 2 terrain - the trail in Granite Park outside Pine Creek in the eastern Sierra has a few Class 2 sections and a mantle or two, most of the trails in The Needles in Canyonlands have mantles or drops in them that would push them into this label. I wouldn’t consider them scrambles in the fun semi-technical sense.

demanding_path is a bit odd to me (as many people consider a long or steep hike on a very nice trail demanding)

I could see this being broken down into a few stages that mimick major changes in ratings, though at this point the only real value would be not having this be a subvalue that people may ignore, but something that has to be entered. I’m not familiar with other regional systems, but they should be tested to see how they map onto this (countries that only have 3 are an interesting case, etc).

highway=path Class 1 YDS, SAC 1-2

highway=demanding-path Class 2 YDS, SAC 3

highway=scramble Class 3 YDS, SAC 4-5

highway=mountaineering Class 4 YDS, SAC 6

Breaking down trails in Needles that have some mantles, steps carved into sandstone, via ferrata, etc from those that are just simple single track into categories seems useful for your everyday tourist even if they aren’t “scrambling”.

As an aside:

How you move over terrain in reality is independent of exposure - one can walk on fatally exposed Class 1/2 (a foot wide but mostly flat ridge), or do a short Class 4 SAC 5/6 section which is short and unexposed but requires more technical or athletic skill than the average hiker has. In YDS I will personally shorthand things like “2 X” and “4 PG”, breaking apart technique and exposure into their own axii, but creating new technique and exposure keys is probably too much for this use case.

The following photo shows terrain where we didn’t have to use our hands, but is exposed. It’s still steep enough (and with enough variation that we had to “read” when to stay high or go low etc) that I wouldn’t put it as Class 1, but even at Class 2 it’ll unnerve some people that are comfortable in general on that terrain type. Is it SAC 2 due to the terrain, or SAC 4 due to being exposed?


This is a bit off topic, we could create a new thread for this… but to answer your question: it’s the hardest part of a hike that determines the overall level of difficulty, so SAC 4 (alpine hiking)?

I think you have to ignore the names a bit, your example isn’t “alpine” hiking either but it does have a similar level of exposure as many alpine hiking paths:

But in terms of ‘hardness’ or ‘technique’ though it is SAC 2 - it’s terrain where we didn’t have to use our hands for balance. It’s just pretty exposed without any via Ferrata, which is a descriptor of SAC 4.

If you view it solely through exposure it would be at least SAC 4, if you view it as movement it definitely isn’t “Use of hands needed in order to advance in certain places” and would SAC 2. It has aspects of both ratings, but also mutually exclusive aspects. The descriptions on the wiki prioritize movement technique over exposure. Someone could argue is should be SAC T2 based on movement and be right, someone else could argue it should be SAC T4 based on exposure and be right. That’s non-ideal to me.

Something SAC T2 X would be clearer, but probably too granular for a wiki. :slight_smile: You could also have SAC T4 PG where there’s a 2-3 meter tall bit of climbing to be done that isn’t exposed.

I don’t really think it makes sense to break this out, but something to think about with ratings.

A clearer way of putting it is I think the term is a bit ambiguous. I would personally find doing a 50km trail in one day demanding, even if it was flat and perfectly made just from a personal fitness standpoint. :stuck_out_tongue: I’m not sure what I’d change it to, and it works pretty well.

A scramble is a scramble (it is referenced as a noun in T4 of the sac_state description).

I’ve also rolled my eyes a bit at the alpine climbing description as I’ve used it in the southwest. :slight_smile: In this case we’re on a solid slab of rock that makes up a large ridge above treeline (mostly dwarf junipers) which is actually pretty close to the spirit of it. Here’s a shot looking down after we crossed over a pass and walked along the ridgeline a bit. The white/red layer on the opposite side matches where we were elevation wise, though in the previous photo we were above a higher side canyon.

I think dropping the mountaineering in my proposal above might be simpler. This is more thinking out loud than a formal language proposal.

highway=path - what any person able enough to walk and moderately fit is capable of doing.

Class 1 YDS, SAC T1-2, Austria Blue, SWW Yellow, CAI T & E

highway=demanding-path - might need hands for balance, or require some upper body strength (I guess a ladder or mantle would fall in here?) but you’re not climbing rock or have any significant direct exposure. having some experience hiking is highly recommended, but you don’t need to be a climber.

Class 2 YDS, SAC T3, UAII 1, Austria Red, SWW White-red-white, CAI EE

highway=scramble - requires use of hands to pull yourself up terrain. it’s generally simple climbing that is done without a rope but may be uncomfortable to people without technical experience and have fatal consequences. While far simpler than technical climbing, having climbing experience will help greatly. Via Ferrata routes with anything complicated than a ladder or a railing would probably fall into a scramble due to technique and physical strength required?

Class 3 YDS, SAC T4-6, UAII 2, Austria Black, SWW White-blue-white, BMC Grade 1, Schall Scale A, Hüssler Scale K1

(I’m not as familiar with Via Ferrata, I find myself usually skipping using it when in Canada, New Zealand, or Patagonia to just make my own way up rock and it isn’t as common in the US where I’m from.)

I think the best way to structure it would be to just map as many existing regional systems into overlapping categories so there’s something familiar for people to reference and then tweak. What are more European, Asian, or South American trail difficulty rating systems?


I think the best way to structure it would be to just map as many existing regional systems into overlapping categories so there’s something familiar for people to reference and then tweak. What are more European, Asian, or South American trail difficulty rating systems?

+1, in Italy there is the cai_scale


Hmm, there’s quite a jump from EE to EEA there. It’s like YDS 2 to 4 with no 3 in between, or SAC 3 to 5-6 with no 4. I edited my post above this with what it sounds like to me and the proposed mappings on the wiki page. I’m going to skip all the Via Ferrata, though I suppose that would automatically make it a scramble if it’s more than just going up a ladder.

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On https://wiki.openstreetmap.org/wiki/DE:Key:sac_scale#Offizielle_Bewertungen_in_Österreich I put a table where I compare, from places that I visited, what OSM has on record in terms of as sac_scale and what on the ground is on the guideposts. I try a quick translate

  • T1…T2 / Hiking : blue (no) dot
  • T2…T3 / Mountain hiking : red dot
  • T3…T5 / Demanding mountain / alpine hiking : black dot
  • T4…T6 / Truly alpine : icon „! Alpine ROUTE“

You can see, there is much overlap. There is a chart below that gives a more theoretical view. In my mind, this is as much rubbish as the charts that compare YDS and UIAA. Some Germans seem quite fond of it, but in Tyrol, nobody uses the Swiss one. Our people are busy enough fixing the local system :slight_smile: And yes, it is in flux!

One more word: Most of the OSM ways T5/6 do not have a guidepost. The „! Alpine ROUTE“ icon is a recent invention. It is used to replace black dots, where there is no path, merely a route. (This has to do with maintenance and liabilities arising thereof.)

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When I was drafting the proposal, I read a lot about YDS. I learned, that it only starts at 5. Below, that is the Sierra Club scale. And there, a 4 is a serious climb.

I also learned, that the Brits (BMC) have a scramble scale. There 3 is a serious climb. So in the proposal, I only referred to YDS 2 rsp. Scramble class 1 as compatible with highway=scramble. Anything above would have to use a different base - highway=path comes to mind - I found it on UIAA VII climbing routes.

The CAI system is much too complicated for OSM use. Quite like the SAC Hiking scale (the original one) it is made to grade routes, not pieces thereof. And it makes that very clear, much more than SAC scale or Austrian grades.

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For the sake of mapping things, I put red as just T3 @ RfC: Highway=Scramble - #82 by erutan - I don’t know any of these systems, or how they are used in the wild, so feel free to argue against my mappings and or point out new ones. :slight_smile:

The Sierra Club is behind YDS, and the two are used interchangeably / the same thing. In fact there’s been like 4 historical versions of YDS which use the same ratings, though it’s been pretty stable since the 30s aside from Class 5 being continuously updated.

Class 4 can be serious, but it overlaps Class 5 up until about 5.5 or 5.6 - most climbing gyms don’t even bother with anything under 5.7 which generally has pretty easy holds and might not entirely vertical. YDS 4 could have some overlap T6. Class 4 is honestly a PITA as it’s the most ambiguous and only directly overlapping rating Class Four is a Myth: Problems in YDS : Articles : SummitPost

EEA referred to bolts, which seems to put it at YDS 5 / UIAA. T, E, and EE seems to fit well enough.

YDS 2 maps pretty clearly to SAC T3, which isn’t quite a “scramble” to me and would I think cover far too many paths. YDS 3 is clearly a scramble, and peak baggers would include YDS 4 as scrambling (honestly I’m not a fan of the new SPS scrambler rating as it makes the classic mistake of smushing together too many aspects of a path and calling Classes 2-4 all “scrambles” makes the word so broad as to be meaningless - that said having a 2.0, 2.1, and 2.2 gives me a little more information than just 2 even if at times I don’t agree with it). I think having a scramble and a demanding-path breaks up technique pretty nicely.

I’ll take a look at BMC.

update: T6 stopping at UAII 2 makes me think it does just top out at YDS 3, as UAII 3 seems to map to YDS 4 a bit better.

In Austria this would be a black path. Exposure is part of what is considered. There is no formal document by the alpine club, but the administration has some write-up regarding quality seals.

This has seen quite some shift, so hiking mostly is meant as only happening on constructed paths. See picture in the other thread.

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I dropped CAI EEA as it seemed too technical and also dropped YDS 4, and I added in BMC Grade 1 to Scramble.

Scrambling skills: the grades explained BMC guide

I’m finding this useful https://www.bergfreunde.eu/alpine-grades-calculator/

Another example of why we need something like this:


The focus of my proposal was on the fun part. I like to ramble and to scramble - so I learned to say in the meanwhile.

The proposal went to vote, which turned out a belated RfC, so I postponed the vote. I am still willing to work on the details, e.g. spell out, why sac_scale just does not do it.

One prominent supporter was from the biking community - They like scramble, it is kind of a way to say this highway is not good for riding a bike :slight_smile:

When I stopped the vote, a clear majority did support the tag, but not enough to pass the required 75%.

One more caveat: The Bosch appliance already brought about a nice encounter on me with someone on an unsuitable route, Bosch seem to be of the very careless kind of consumers. Short story: There may be routers, that interpret scramble as usable, just because it is in the highway key. Any knowledge on that?


Sooo… What’s the consensus on this? Should I be using highway=scramble? Looks like there are 22 uses so far.

I’ve tagged climbing access routes a few different ways and they all feel wrong to me:

These things do get notated on other maps, so they are useful to help people navigate (“Yes, you should expect to scramble here, it’s not class 5, you’re still on the right path”):