RfC: Highway=Scramble

General talk Tagging general discussion
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A “highway=scramble” is similar to a “highway=path”, but it is lacking in some ways. Most eminently, the trail is not continuously visible on the ground, especially when it passes over bare rock or blocky scree for example. Yet, people commonly manage to follow along, by looking at markers, cairns, take time for orienteering, spotting the continuation a bit further, consulting with a guide, and so on. It takes a bit of training. Second most eminently, in contrast to a “highway=path” a “highway=scramble” may and will comprise non-walkable sections, where using ones hands is required to get along. In some cases, ropes will be beneficial, if not necessary.

Useful combinations are: sac_scale=*, trail_visibility=*, assisted_trail=*, trail_blazed=*, scramble=grade*, climbing:grade:uiaa=*, and so on.

Scrambling combines hiking and climbing into an activity, where the goal is to traverse or reach points of interest in terrain that is neither welcoming to walking without first becoming knowledgeable of both the route and the area. Eventual climbs are not so spectacular as to merit mapping them as a climbing route. Scrambling calls for a diverse set of skills yet rarely requires extensive preparations. Good boots mostly will do, as fas as technical equipment is concerned. It is exercised in leisure time by a number of people.

Difficulties preferably get attributed in the spirit of the SAC scale for whole sections of a scramble at easily reproducible waypoints, e.g. where ways branching or at intermediate goals, in order to have them discoverable in overview renderings.

Which brings us to: Rendering: It is highly unlikely, that the standard map will render “highway=scramble” any time soon. Special maps or smartphone apps geared towards hikers can easily add rendering, if treating the same as “highway=path” and applying their usual styling that knows some of the attributes used in combination already. With enough adoption of the tag, micro-mapping facilities should come to life, that renderers can use to decorate noteworthy waypoints in scrambles with useful icons.

Description is copied from “RfC: Sport=Mountaineering” with only little changes and some additions. During the discussion there, I learned that my hearts desire actually goes for something more mundane, a “Here the fun begins” tag. Reading up on the Selvaggio Blu in Sardegna, a bit more research later I found Walk up Snowdon in Wales, and immediately found myself at home.

Currently, scrambles here get mapped with the “highway=path” tag. Alone in the area of my local knowledge I know of several. During the discussion on mountaineering I also learned, that “path” not only often does not fit, but actually stands in the way of mapping scrambles reasonable.

Therefore the idea, to propose “highway=scramble” as a base tag. Please share your thoughts!

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half kidding here: why not highway = none?

We are having a debate on the French-speaking OSM forum about removing a path that apparently has no reality on the ground but still belongs to a route (it is in a rocky place). This led me to mentioning other circumstances where “non-paths” are used in routes: pedestrians areas in towns, some meadows, flat rocky areas, beaches.

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Because scramble is much nicer sounding than none :slight_smile: Just as “highway=bus stop” sounds nicer than “none” - And we need to differentiate between all those “none”, where there is nothing there, still we regularly observe people standing waiting, walking hiking, scrambling mountaineering… Too few of them, perhaps to make a dent, especially on asphalt or rock.

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I won’t fight to defend “none” :slight_smile:

Still, there are weaknesses to “scrambling” that “none” has not:

  • it describes a human activity while other values of “highway” describe types of ways
  • it is fairly specific to mountaineering, while there are other use cases for ways-that-are-not-real-ways.
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It doesn’t seem useful to use the same tag for situations that applications must not treat the same.

A router should use “non-paths” across pedestrian areas pretty much like a pedestrian road, but clearly should not use a difficult route in mountainous terrain like a pedestrian road.

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Would you find “scrambleway” better? That would bring it in line with bridleway, cycleway, driveway, footway (in German called “Gehweg”, a way to walk on).

I found scrambling as a term, that does not depend so much on high altitude as mountaineering. While scramblers climb mountains, they hike hills as well, or steep coastal areas.

I’d be very much interested on native speakers comments on the term. I read it in statements of British and South African accounts. It is sometimes used like a pejorative, but there is even a Wikipedia article on it. From the pictures, it looks a lot like mountain hiking, up to sac_scale T6. But not requiring the extra glacier gear.

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often these undefined paths in the mountains are not difficult but are the easy passages where you cross a field of rock or stones and can walk everywhere, so it is neither visible from other people’s traces nor from the topography where exactly the path should be. There is no defined path, but there is also clearly a connection, it is part of the route. IMHO with trail_visibility we can sufficiently describe the situation.

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I did check highway=path and sac_scale and trail_visibility are already mentioned there so my question is why not keep these ways tagged as highway=path with for example trail_visibility=bad. That follows highway=track + track_type=.

When proposing a new tag it is always good to also think how it should be rendered, is that the same as a path (for now) then let’s map it as a path. A new tag means that for quite some time the path will not be rendered as the example for highway=busway is showing.

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I’d be very much interested on native speakers comments on the term. I read it in statements of British and South African accounts. It is sometimes used like a pejorative, but there is even a Wikipedia article on it. From the pictures, it looks a lot like mountain hiking, up to sac_scale T6. But not requiring the extra glacier gear.

I can comment on this from my perspective. In American English, “scrambling” is an outdoor activity in between hiking and climbing. A scramble is a route that ascends up some rock. Ascending the route will require the use of your hands (at the very least for balance, and possibly also to help propel you upwards). A rope is not typically used, because the risk of falling is lower and the consequences of a fall may be less dire (though a fall can still be very dangerous).

In the Yosemite Decimal System for rating climb difficulty, a “scramble” is a Class 2 or Class 3. I believe that in the UIAA system a scramble is a Grade I or Grade II, but I have less familiarity with that rating system so perhaps someone else can confirm or correct that.

I found this photo on Wikimedia Commons which I think illustrates “scrambling” pretty well. You can see from the people’s posture that the slope is not vertical; it’s probably closer to 45°. They are using their hands on the rock in front of them for balance, but loosing grip on a handhold probably wouldn’t cause a catastrophic fall like it might in rock climbing.

I live in a mountainous part of the U.S., and “scrambling” is a pretty familiar term in the outdoor communities here. It’s not uncommon for hikes (especially those whose destination is a summit) to end in a scramble. Some people aren’t comfortable with that sort of thing, and others are specifically seeking it out, so trip reports and guidebooks will almost always mention whether a peak requires scrambling to reach or whether it’s a “walk-up”.

In my area, most of these scrambles are currently mapped as highway=path in OSM. Usually the way that represents the walkable trail goes all the way up to the summit, ignoring a transition from walking to scrambling in the final few hundred feet. I think it would be great if this last segment of the journey were tagged differently so that specialized renderers could display this information. And I think it would be best if the tagging for the scrambling portion did not use highway=path, so that non-specialized renderers wouldn’t imply that there is a walking route to a summit when in fact none exists (and scrambling is required to reach the top).

My preference would be to use the existing tags for climbing routes to tag scrambles. I think that set of tags is already designed to cover this use case, it just hasn’t been widely applied yet. A way can be tagged climbing=route along with climbing:grade:uiaa=1 to indicate an easy scramble, or climbing:grade:uiaa=2 to indicate a more difficult one. Other scales (like YDS) can also be used if they’re more appropriate for the local context.

The benefit that I see for using these tags rather than creating a new category for scrambling is that the boundary between scrambling and climbing can be quite fuzzy, and it’ll be hard to define that boundary for OSM’s purposes in a way that is verifiable. By using the climbing tags, we can make this distinction using the standard climbing rating that are already in widespread use in the outdoor community.

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Hello Jake, exactly what I’ve been wishing for. The picture, in my understanding, shows a solid “alpine_hiking/T4” according to the SAC scale. If it was just a few meters, say single digit, it might be covered by “demanding_mountain_hiking/T3” too. I’d say in UIAA its a 1, not climbing, but not walking neither.

I am with you, that renderers and routers shall select for these features, and not get them as a by-pack to footways or other kinds of paths. The most sure-fire way of having something not mapped path is using the highway key, as has been proposed in the mountaineering topic.

I have been looking at the climbing namespace too. I fear, that their route tag is not a good fit; After all, it is about climbing routes, that mostly are mapped as a single node and only rarely as a way. It feels a bit of an abuse to me, to use that for such non-climbings. Using just climbing:grade would not trigger such bad feelings, and nothing speaks against using this on a highway=scramble, I have seen it on highway=path too. Besides, QA tools would not have to claim “missing physical feature on climbing”.

The term seems to be a bit wider in Wales.

PS: No ropes, I got it, just boots :slight_smile:

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This tag will probably never rendered on the standard view. In issue 1500 on the OSM Carto tracker, it was proposed, to instead render some small dots … like an ellipsis in typography, where the scramble starts, to indicate, that there is a continuation. Special maps and your smartphone app will render it in all appropriate glory.

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If that is the case and people are happy with it, an separate tag is the way to go.

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Some reading later, I conclude, that the Welsh use the term in just the same way as Jake from the US: From the point on, where hands are needed, walking ends and scrambling starts. Use of hands therefore is the single most defining feature, be it for keeping balance, be it for pulling up. Trail visibility is a nice add-on attribute, in the same class as trail blazing or assisting measures.

On a side-note: This reminds me of the history of alpine hiking, a 150 years ago: The Britons had quite some say in this; For them, use of hands was not something, that a lordly person would do, in order to advance. So locals performed long searches, to find ways for their customers, on which to reach the summit in a walk-up. Quite often here, these sections are mid-route, one has to get by one or more “steps” in the terrain, where continuation is not immediately obvious and the itinerary seems puzzling at first.

Here it says https://www.walkupsnowdon.co.uk/snowdonia-walks/crib-goch/

3 The path from this point on becomes a full on scramble…

One may read this: path=walk turns into path=scramble. I’d say, the difference warrants the scramble a top level entry in OSM tagging. Data consumers should be able to rely on path=walk being the default and not having to look at extra attributes that override the assumption.

Thank you all for the valuable input! Maybe meet on the Wiki!

https://wiki.openstreetmap.org/wiki/Proposed_features/highway%3Dscramble

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I think this idea has merit, but it’s important to note that an unintendended consequence of introducing this new tag highway=scramble would be the fragmentation of existing hiking trails. Many mountain trails include sections that require scrambling, and they aren’t just at the top. As these sections get converted from their current highway=path|footway to the new tag, they will appear as gaps on many existing hiking maps until they start rendering the new tag. It is stated in this thread that some renderers would likely never display highway=scramble. That being the case, the gaps would be permanent. Perhaps the idea is that this new tag would only be for full scrambling routes that really aren’t trails in any sense, and short scrambling sections of trails would be excluded. That seems like a tricky distinction to document, though.

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I’d say, the renderers most likely to never display this new tag, are also the ones, that do not display hiking route relations now. Gaps indeed will show up badly. A welcome incentive to update data import strategies, for those who care :wink:

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For trails, if they are mapped as route relations that needn’t happen. Here is an example which is shown like this in a pedestrian map style and like this on “Waymarked Trails” (which is pretty much the gold standard for hiking routes).

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A similar example from Ireland: “To reach the summit, you’ll need to spend a short time balancing on hands and feet in the final scramble to the top”. I found lots of pages about hiking this mountain (a popular hike for beginners/families in Ireland) that use very similar words. The proposed highway=scramble seems suitable to me to map the paths at the top of that mountain that are currently tagged as sac_scale=demanding_mountain_hiking. I don’t think it would be problem if those sections disappeared from “generic” maps - if it discourages people from using unsuitable map renderings for outdoor recreation, all the better.

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I agree with those proposing a new highway=* value. I’m fine with highway=scramble or some other value.

One of the challenges we face in OSM is that highway=path is so overloaded and expansive that it can mean anything from a paved concrete sidewalk through a city park to mountaineering routes requiring ropes and anchors to protect from falls. The ends of this spectrum are fundamentally different even if there is a continuum between them.

A corollary is the road network: There might be a lot of gray-area between highway=primary and highway=secondary , but in most cases no one is going to confuse a road tagged with either of those with highway=residential or highway=motorway. Breaking the spectrum of roads into broad chunks isn’t always straight forward (and can require retagging due to misconceptions), but doing so makes the road network more intelligible to data consumers.

The proposal being discussed to segment off one end of this spectrum based on some relatively clear distinctions seems like a useful way to begin to reduce the scope of highway=path to something slightly more constrained.

Additionally, as was mentioned in another thread, there are real-life consequences to having naive renderers and routers treating all highway=path in the same fashion whether they are paved sidewalks, maintained walking trails, or mountaineering routes. By moving the most dangerous types of foot-traveled routes out of highway=path and off into highway=scramble data consumers will default to a “more-safe” gap if they don’t understand how to handle such potentially dangerous ways.

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We have contributors that have mapped highway=path, trail_visibility =no, sac_scale=demanding_mountain_hiking for years (if not more than a decade).
This has been crafted by hand, and also by feet and sweat in this particular case.
Proposing highway=scramble or else as a synonym will end up as it is: an alias, and you will find either way of tagging in the database for the next decades.

If some data consumers fail to recognise long established keys such as trail_visibility and sac_scale, what do we hope to achieve with a new tag? More case to dealt with in a style sheet? More omissions?

I always found that the best way to deal with helplessness is education.

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An OverPass query for
highway=path and (sac_scale=demanding_mountain_hiking or sac_scale=alpine_hiking or sac_scale=demanding_alpine_hiking or sac_scale=difficult_alpine_hiking)
does a good job of finding candidates for retagging. According to taginfo there are 59,939 ways with the four highest sac_scale=* values and with the top three values only having ~20,000 uses. Retagging these from highway=path to highway=scramble would not be an insurmountable job if a proposal like this goes through. With a bit of local knowledge tagging could likely be updated without requiring a re-survey.

While education is ideal, many map renderers simply don’t care about mountaineering details – many build maps targeting an urban user base and show paths to get their park renderings looking good. Their users then try to use those same map renderings in the wild and get themselves into trouble because wild areas are crisscrossed by undifferentiated paths.

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