RFC: Highway=Mountaineering

That’s the whole point of suggesting highway=mountaineering instead of sport=mountaineering. It cannot be used in parallel with highway=path. All the other secondary tags will stay the same. If a data consumer targets mountain sports, they surely already look at sac_scale, so they only need to add a rule that says handle highway=mountaineering like highway=path. For everybody else, the ways simply disappear. So data consumers should have to make an active choice to include the path but once they do, it’s really simple to handle.

If you refer to the fact that there is going to be a vocal minority of mappers who insist that they could climb the Matterhorn barefoot and therefore will keep using highway=path no matter what, then yes, I’m sure there will be some. That cannot be helped. Still, even if not all ways are changed, the ones that are adapted already make the situation better.

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My favourite so far, thus another try at camera ready documentation:


Mountaineering combines hiking and climbing into an activity, where the goal is to reach points of interest in mountainous regions, be that summits, or viewpoints on ridges and saddles. Typically, the terrain is neither welcoming to hiking without first becoming knowledgeable of both the route and the area, nor are the climbs so spectacular as to merit mapping them as a climbing route. Mountaineering calls for a diverse set of skills and can require extensive preparations. Mountaineering is exercised in leisure time by a number of people, it can grow into a sport in its own right even.

The basic on-the-ground feature that supports mountaineering is the route. It can be mapped with the tag “highway=mountaineering”. A route 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, spotting the continuation a bit further, and so on. It takes a bit of training. Second most eminently, in contrast to a “highway=path” a “highway=mountaineering” may comprise non-walkable sections, where using ones hands is required to get along.

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

When attributing difficulties, the most demanding section is to be used for the whole of the trail. Mountaineering trails shall not get split, where the difficulty changes, but only at places, where there is a goal to be reached.

I came to Openstreetmap for the richness of data for hiking. I am very certain, the smartphone app, that I use, when on the way, will support this tag.

I’d really like to make the tag applicable too, when the goal taken is not a high altitude point of interest, but the route chosen requires mountaineering skills, e.g. to the mid-route hut through a gorge. Will ponder a formulation… any help welcome.

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We really need to be pro-active to get this new tag on osm-carto, 'cause Tagging something to make it disappear from The Map will not get much traction…

This is not really sustainable for ways, this make it looks like a tag for route relations.

I disagree that that should be necessary because osm-carto should not decide how to tag things and my impression is that they are quite reluctant to add new features to the map. But of course in practice things on carto will be mapped more frequently. Therefore it is still a good idea to ask carto to render it.

That’s my opinion as well. Now there are highway=path sections that can be accessed by highway=steps only and we only tag the stairs as stairs. This way data users can decide what to do: Show the actual situation of a section of way or use tags of the route relation to show the situation along all of a route.

IMHO it would be more effective to add a map layer that does show it, like for example opentopomap. Carto lacks nearly everything you’ll want to know for such ways like contour lines, sac_scale, trail_visibility, via ferrata, hiking routes, etc. so what’s the point to show the way without this information? You could get some of this with overlays, but it’s not like people are using carto to go mountaineering, there are plenty of applications which are much more suited for that.

The prompt, to not split when difficulty alone changes, directly mirrors the SAC guidelines. I personally find it perplexing, when the route to Praxmarerkarspitze over 2.3km from where it splits from the route to Kaskarspitze, changes from alpine_hiking to demanding_mountain_hiking, then back to alpine_hiking, then to simple mountain_hiking to become demanding_alpine_hiking in the last third. That reminds me of so-called Topos from via ferratas. I do not see much sense in such micro-mapping mountaineering routes, and it does not square with the spirit of sac_scale.

As to rendering, special maps of course will show the paths however blunt or unimposing as deemed fit for their purposes. Regarding OSM Carto: In issue 1500 a maintainer proposed to render some dots, like an ellipsis in typography, where the mountaineering route leaves the well trodden hiking trail. It won’t help anybody out there though, where cell network coverage often is poor, but might inspire app developers. It might be useful to map a short path segment, where the start of a mountaineering route is excellent in visibility, to aid hikers to follow verbal directions that count crossings.

Does the “not splitting” approach require a clear definition of what exactly defines a single “route”? I generally walk on relatively easy hiking trails, but sometimes when I come across a difficult section that requires use of hands, I tag that using sac_scale, only on the difficult section. I am not sure how I would apply it to the “whole of the trail” - how do I know where the trail starts and ends?


Same as Alan. Also, when micromapped that way, it is possible to to get the highest or average or whatever metric of the difficulty of an itinerary.

I do not have the intention to make sac_scale tagging exclusive to highway=mountaineering. Down from Praxmarerkarspitz Node: ‪Östliche Praxmarerkarspitze‬ (‪1620258653‬) | OpenStreetMap to the next guidepost Node: 3815459868 | OpenStreetMap one could split a hundred times too. I consider the guidepost a valid point for a split, as any other parting of ways, or intermediate goals. Those also are much easier to reproducibly determine, than changes in difficulty alone. But this is bordering on getting off-topic.

Not really of topic: if sac_scale changes along an itinerary (which is normal in my point of view), then highway could reasonably change from mountaineering to path back and forth.
This a reason why I wouldn’t be found of this new tag, because it is redundant with highway=path and subtags.

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I found something in the data, that may resemble, what I understand from your comment: There are two occurrences of “highway=climbing; climbing=route” in all of OSM data. There are no climbing routes there. If you want to micro-map, “highway=mountaineering” would be just as useful as that indeed.

On the other hand, I am not sure, what to think of mappings like e.g. this one here - Way: 1050234319 | OpenStreetMap - They certainly block routers, while they are quite capable of hiding the abseil from unsuspecting hikers, that look at a rendered map. I’d say, the abseil is much better mapped as a node, after all, a vertical “highway” makes a node. With a base different from “highway=path” that allows for that, consumers can decorate them with nice icons. A welcome consequence of such another base tag will be, to sharpen the meaning of “path”, which is much too broad, to be of use for the majority of consumers.

Speaking of niche tags, I didn’t know this one : https://wiki.openstreetmap.org/wiki/Key:assisted%20trail?uselang=fr

After two years asking questions, I have not found any robust distinction between foot and hiking. Wouldn’t mountaineering just bring the same kind of ambiguous distinction?

I believe there is a notion of scale, as in “zooming to change scale” that is not well captured in current definitions. Even in the steepest of climbing routes we can find extremely small parts that would qualify as “foot path”…

Could things be more clear if we said something like "path difficulty (e.g. sac_scale) must not be translated into a tag (e.g. mountaineering) under a certain length? It seems to me that this kind of principle would bring a series of logical consequences that would help us.

I ventured to start a fresh topic, RfC: Highway=Scramble I tried to address some of the issues brought forward here.

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)

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Please note that I am not against a new highway= value, just I found the limitations on splitting the ways unnecessary and overreaching.

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Another option is ways without tags, but members of a route relation.
See https://wiki.openstreetmap.org/wiki/Tag:route%3Dcanoe

“Canoe routes can include waterways, untagged lines showing the approximate path in a pond or lake,…”

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Especially for short sections of marked trail across rock, passable to typical people, I would still mark it as path/footway.

And would treat marks on rock (smoothened rock, vegetation removed, lichen scrubbed or trail signs) as sufficient to overtake “has no reality on the ground”. See say File:Krywan podejscie.jpg - Wikimedia Commons or another view showing marks on rock (also on top, where solid rock is present).

But note that there is Tag:highway=no - OpenStreetMap Wiki has already over 2000 uses

However, occasionally, there may be ways that one would expect to be highways, but are not. In this case, highway=no can be added to explicitly indicated to other mappers and data users that there is no highway here. This allows us to distinguish between the case of a highway type being unknown and needing to be determined, and the case of the way being known not to be a highway.

For example, in the UK, there are sometimes legal Rights of Way that are inaccessible, resulting in a legal highway that is not physically present or usable on the ground. Due to administrative errors, unauthorised constructions or lack of maintenance, the official line of a legal route may pass through dense woodland, though walls of a building a building or though a lake. highway=no can be used in these cases to explicitly mark the way as not being a highway, while still recording the official line.

This tag should not be used to highways that physically exist but have restricted access. This use of this tag for such cases is deprecated, in favour of highway=* + access=no.


I’d say, the “path” up Mount Everest deserves “highway=mountaineering”. Such a key would be perfect, to fix the note you placed there, wouldn’t it?

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not entirely sure - is there even a strict route there? Or various group using navigation markers (like dead bodies) and route is not constant?