RFC: hiking_technique key (or a better name!) to describe movement on paths by hikers


Most mapping clients can show the total elevation gain and distance, and some outdoors focused ones will even show details about the grade. These values can also be inferred by looking at the topo map itself, or the incline key if present. To me “difficulty” doesn’t need to include the basic metrics of a hike, but rather the terrain present and the way it is moved over. The former can have many aspects to it, the latter can be broken down into 3-4 major categories that are useful to describe how a hiking path is interacted with.

I feel this is distinct from smoothness as it tries to map meaningful changes for pedestrians in a way that is fairly objective / verifiable. Using a key with 8 values meant for wheeled vehicles isn’t necessarily helpful - those 8 values essentially cover minor variations of only the first two values here, and cover obstacles up to 24cm or up to 9.4" high. Many more challenging hiking trails would just get graded as impassable under that key.

Note that this key will only map to parts of existing systems, and other systems may fall within multiple values here, they aren’t all a pure one to one mapping. There is still value in including existing systems as it helps validate the thought process as well as giving someone familiar with system C but not A a good starting point. By focusing solely on technique / mode of travel, we clarify a lot of ambiguity. A trail doesn’t need to have a “steady ascent’ ala SAC T2 just the “some sure-footedness” aspect (ironically the sole example for SAC T2 on the OSM wiki does not show a path with a steady ascent). We likewise clear up ambiguity if there is a trail with a T1 technique and T3 exposure etc, as a simple smooth single track dirt trail here will not be tagged as use_of_hands because it happens to be near a cliffside and feels exposed.

I’m not sold on the particular wording of either the key or values, :slight_smile: I’ve played with path_locomotion, path_technique, path_traversal, hiking_technique, hiking_mobility etc. mode_of_traversal is probably makes the most sense but is a mouthful… I’ve moved from even_ground to even to simple_walking, uneven_ground to etc. complex_walking doesn’t feel quite right, but “challenging” or “demanding” feel more subjective.

Key Values

Value 1: casual walking


Falls under: Class 1 YDS, NFS Class 2-5, SAC T1 / Yellow, Austria Blue, CAI T, AWTGS Grades 1-2, PWS W1 & W2

Obstacles: The ground may not be entirely smooth and have some irregularities, but it has few obstacles and none over knee height that cannot be avoided. It isn’t uncommon for these trails to use imported materials for their surfaces, but can also be on compacted or naturally even ground.

Slope: Flat to moderate.


  • Be able to casually walk. Casual walking paths that wheelchair accessible should be tagged with wheelchair=yes.
  • Almost all casual footwear will be adequate.
  • Little to no focus needed for traction, people can walk and talk and not pay much attention to the path surface.

Useful related keys:

  • wheelchair=* should be added for even paths that are wheelchair accessible
  • highway=steps should be used if there are constructed steps on a path
  • smoothness=* is currently only for vehicular ways, but IMO should be applicable here. Wheelchair accessible paths should definitely include this.
  • surface=* can help predict footing - a path which is paved or is made of gravel will tend to be more even than one out of dirt.

Value 2: surefooted walking


Falls under: Class 1 YDS, NFS Class 1-3, SAC T2 / White-Red-White, Austria Red, CAI E, AWTGS Grade 3?, PWS T1-T2

Obstacles: The path has around ankle to knee high obstacles (roots, rocks, etc) that need to be stepped on / passed through to proceed forward.

Slope: Flat to moderate.


  • Able to walk with balance, coordination, and sure-footedness.
  • Footwear more consequential but trail runners etc should be fine, flip flops and high heels could get awkward.
  • Attention will need to paid to footing in places to avoid loss of traction / tripping.

Useful related keys:

  • highway=steps should be used if there are constructed steps on a path
  • surface=* can help predict footing, a compacted trail with some roots or rocks is different than a sandy “sloggy” trail etc. this can also be misleading, as obstacles in the path surface are not included here
  • smoothness=* is currently only for vehicular ways, but IMO should be applicable here

Value 3: use of hands required


Falls under: Class 2 YDS, NFS Class 1-2, SAC T3 / White-Red-White, UAII 1, Austria Black, SWW White-red-white, CAI EE, AWTGS 3-4?, PWS T3-T4?, BMC Grade 1

Obstacles: The path consists of obstacles roughly knee to shoulder high that need to crossed. While both feet may be off the ground for a mantle, this is generally just for a few seconds and doesn’t quite fall into “scrambling”. Terrain could include boulders or talus that are crossed, mantling up onto a higher surface level (or dropping onto a lower one), fallen trees that would not be cleared as part of regular maintenance, etc.

Slope: Even flat terrain can have obstacles on it that require use of hands to surmount. Additionally once terrain gets close to or over 30° hands (or trekking poles) are generally used for support and balance occasionally as the slope itself essentially becomes an obstacle. Many highly developed trails are explicitly designed to avoid such steep angles, but there are exceptions.


  • Enough upper body strength to pull up your body, along with being able to move with balance, coordination, and sure-footedness.
  • Supportive or grippy footwear is recommended (boots, approach shoes, etc).
  • The ability to think a few steps ahead and a little bit of confidence when focusing on the path are very helpful. :slight_smile:

Useful related keys:

  • surface=* honestly this is of less use here, as most large obstacles will be rocks or rock of some kind but parts or most of the path surface may be something else entirely.
  • incline=* shows the steepness of the path in degrees or grade %
  • highway=via_ferrata if there is permanent equipment installed to ease risk or traversal along a path. It can be rated with via_ferrata_scale
  • assisted_trail for the same if it is just for a small section of trail

Value 4: Scrambling


Falls under: Class 3-4 YDS, Bouldering VB, NFS Class 1, SAC T4-6, UAII 2, Austria “Alpine Route”, CAI EE, AWTGS 4-6?, PWS T3-R?, BMC Grade 2-3

Obstacles: High angle obstacles that need to be “climbed” for significant lengths of time finding handholds and footholds and pulling oneself up, but are simpler than technical climbing which use of a rope and harness are expected (see grading systems above). Feet are off the ground for more than a few moves, or there are repeated sections of short climbing. This is going to be a slim minority of paths in many regions.

Slope: Generally moderate to high angle.


  • Good grippy footwear, being physically fit,
  • Approach shoes, “high route shoes”, cross trainers, or boots are recommended.
  • While not considered “technical climbing” significant risk is often involved. Previous climbing or mountaineering experience is highly recommended,

Useful related keys:

  • surface=* most likely rock
  • incline=* shows the steepness of the path in degrees or grade %
  • highway=via_ferrata if there is permanent equipment installed to ease risk or traversal along a path. It can be rated with via_ferrata_scale
  • assisted_trail for the same if it is just for a small section of trail

Links to different rating systems

YDS & Bouldering

NFS Trail Classifications (loose and not 100% predictive for higher grades)

SAC & friends






https://www.cai.it/wp-content/uploads/2021/12/allegato-circolare-22_2021-Classificazione-difficoltà.pdf (pdf in Italian)

https://www.bielointothewild.com/hiking-in-italy-understanding-the-difficulty-of-a-hiking-trail/ (good unofficial write up)


Tasmanian PWS

Further thoughts

I was originally not going to have two levels below “use of hands” to help keep things less ambiguous (more like the YDS breakdown than CAI/SAC), but I think there’s value in breaking walking into two levels:

Some AllTrails comments for what I’d consider NFS 3 / easy SAC T2 / YDS 1 terrain on a ~2.5 mile loop with less than 300 feet of low grade elevation gain change:

https://www.alltrails.com/trail/us/washington/little-cranberry-lake-inner-loop “This trail is NOT easy. There are many tree roots and sharp rocks on the trail with barely any sections that are even and easy. Wear good boots and if you’re a beginner (like me)… do NOT go alone. The scenery IS beautiful…”

https://www.alltrails.com/trail/us/washington/little-cranberry-lake-and-trail-100-loop “Not an easy hike, probably moderate. Trails nearest lake are rocky. Trail through forest easier. Beautiful hike.” and “Rated as an easy hike. I would say it’s near moderate due to roots and rocky terrain. Experienced hikers will breeze through it, but novice hikers beware of your footing. You may take an involuntary bath in Cranberry Lake.”

I’m unsure of slope here - I didn’t have it at first, thought perhaps the first tier should be capped at ~20° for the sake of it being either even_ground or simple_walking aimed at tourists, which then means the second one would probably be capped somewhere around 30° (which I’m less happy about), but that’s beginning to feel a bit annoying.

Some related thoughts about separation of concerns here.

One complaint could be the wording of simple_walking and complex_walking for multi-use trails. Going back to even_ground and uneven_ground would solve that, but mix the mental model a bit. My understanding is that once we get to use use_of_hands is that MTB users are in trials technique level terrain, but the two systems can co-exist.

If someone from a country that uses a system I’m referencing feels I am misrepresenting it, please let me know! This is a best faith effort by someone that has never used them. :slight_smile:

There is an existing key for assisted trails, so via ferrata can be ignored I think, and glacier travel is niche and it’s own beast.

Scrambling could include YDS 4, BMC 3, or cut-off below that as indicated here. These are “ropes recommended” ratings, though experienced individuals do without them and they tend to overlap with actual climbing routes (YDS 4 overlaps to around YDS 5.5) and BMC-3 is described by the agency as “Grade 3 scrambles often appear in climbing guides as ‘Moderately’ graded climbing routes […] Use of the rope is to be expected for several sections, which may be up to about Difficult in rock climbing standards.”


If you’re devising a tag solely relevant to hikers, put something about hiking or walking in the key name.

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Indeed if this is about hiking difficulty, then hiking_difficulty=* would make that clear and would be a good name for the key.
I like your proposal so far, esp that it matches with SAC scale so that the present tagging can be easily converted to the new key. For the easiest level, smoothness can be used to give more detail if wanted (smoothness=excellent/good means “no need to watch your step, high heels OK”, smoothness=bad means “high risk of twisting your ankle, hiking boots recommended”, etc.).
Maybe you could give links to background info for the abbreviations you use?

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Changed to hiking_technique based on feedback. I wasn’t happy with anything I came up with honestly.

I don’t like “difficulty” because it beings to mind easy, moderate, hard - which is subjective. A hard trail for an elderly tourist would be easy to an experienced mountaineer. If I had to try and do a 40 mile trail that was the simplest mobility/technique rating here I would find that difficult. I have a hard time thinking of a simple two word key (I originally just chose path_mobility as it is focused on highway=path and some highly developed e.g. paved paths aren’t always considered true hiking).


are probably the best two word solutions.

Those are all different international standards - I would link out to pages referencing them in the final version but they are there more as a guiding principle than the expectation they would all be checked.

It’s not quite a 100% match, use_of_hands maps to SAC 3 but includes mantles and drops which I assume would technically T4, but feel worth pulling out of scrambling since they are short, require a different skillset, and occur on maintained trails far more often.

smoothness isn’t really suited for pedestrian paths as is (it’s explicitly for roads that are made for wheeled traffic). The only value that mentions foot traffic is impassable lol. The smoothness scale is so granular for foot traffic (intermediate and above are considered wheelchair accessible), most variations of bad smoothness and below include differences of 4cm differences in obstacles etc. The worst rating tops off with an unevenness of a bit over 9", which really isn’t that high in terms of what can occur on hiking paths unless we just use impassable for everything above that. Perhaps we have a shadow system for pedestrians that uses its values, but they mean other things? That seems messy.

Bad has a maximum of 5.5" obstacles, that’s not something where I would say someone should wear boots to avoid a sprained ankle though some mention of footwear is appropriate (no high heels or flip flops). My partner regularly backpacks in mixed T1-T4 terrain using the following shoes, though she also carries a pair of La Sportive TX4 Mids for heavy scree/shale or something semi-technical where we’re doing foot jams etc:

If there was a separate sub-section on the smoothness page with a few values called out and described for pedestrian use we could essentially just collapse the first two into one category like I had originally envisioned, and then use smoothness < bad to pull out SAC T1 & T2 and CAI T & E. That distinction IMO has to be mode, but they are the same mode of travel with a complication of obstacles - it’s not as intuitive for a new mapper but that is the more OSM way of doing it I think.

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One issue with doing a flat find and replace with this key (but also helps show why it is useful) is that people are tagging trails that are simple_walking as T2/T3 because they are exposed. Realistically someone looking at T3 that understands what that means would assume it’d be as rough as use_of_hands, which is what it would be changed to in a one to one comparison.

I feel like this key would exist on top of older ratings for a while and be used in an if hiking_technique, else sac_scale kind of way.

update: while not quite as OSMy as this proposal, I basically already had this written already for something else and just had to adapt it. RFC: hiking_exposure key (along with hiking_technique this disambiguates sac_scale)

So now there can be a simple_walking path with R exposure, a use_of_hands path with PG exposure, etc. SAC T2-6 exposure is pretty confusing on the OSM wiki, I feel like these basic buckets make sense

G- not exposed and no real risk of falling
PG - greater risk of falling, but still unexposed
R - indirectly exposed, falls could be serious but somewhat unlikely
X - fatal exposure, you lose traction you dead

renamed the first two values to casual walking and surefooted walking based on some comments I made in another thread. that feels more intuitive than simple and complex.

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As a novice hiker, and new OSM tagger, I appreciate efforts like this to clarify the tagging schemes and harmonize across different scales.

At least one of the classification systems differentiate an “accessible” level (e.g. AWGS 1) which would be a key value “easier” than those proposed. There are paths/trails which would meet this criteria, and as a hiker with a family member who uses a walker or a wheelchair, I would appreciate being able to identify/differentiate those paths we could do together. I think this level would be distinct from Value 1 given potential criteria below. Fewer key values and simplicity in the scale are clearly desirable, but also delineating paths to include the full range of walking ability would also be desirable.

Value 0: Accessible

Obstacles: Flat even surface with no steps or steep sections. No obstacles present (<1”).
Slope: Flat (<8% grade)
Requirements: Suitable for wheelchair users or those using a walker.
surface: Hardened or surfaced (Asphalt, Chipseal, Fine Gravel, Paved, Concrete, paving_stones, Compacted, metal, wood)
smoothness= Excellent, Good, Intermediate (directly applicable IMO as the requirements relate to a wheeled mode)

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I had thought about suggesting making the second word “accessibility”, but I almost feel like that’s a different all together then what these tags are trying to get at. Like you can have a trail that is accessible and still requires some mountaineering experience once you hike it a ways. Maybe there’s some correlation I’m missing there though :man_shrugging:

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I’m a non-novice hiker, but a relatively new OSM tagger. Perhaps that has some direct value because I’m not too used to the old broken way. :slight_smile:

The current thinking is that the existing wheelchair=yes would be applied to a highway=path tagged with hiking_technique=casual_walking. That key is already used by mapping clients to show wheelchair accessible paths, so it seems like the best way to go (whether or not this key makes it or not). Does that seem like a good solution to you?

One other thing to keep in mind is that there is some interest in having NFS trail classifications listed (to be taken with a grain of salt, but it seems like they could be slurped in from a NFS source if there was a key here) and NFS Class 5 tends to be accessible.

Good point. :slight_smile:

From a certain angle the trails would be accessible based on comfort of the mode of transit, or someone having enough fitness and technique, but that does tend to bring formal “accessibility” to mind.

I still don’t have a great grasp on norms of when to split a way into a new segment because something has changed (apparently because there are none). I did it once where a casual_walking path ended up in a technical climb with bolts (sandy wash leading to a slot canyon). I think if the first 80% of a hike is casual_walking, and then it switches to use_of_hands or scrambling it’d be worth splitting a new segment so the first 80% can be stippled more prominently than the last 20%.

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Agree, that applying wheelchair=yes to all paths which are wheelchair accessible is the way to go. :smiley:

My suggestion is that such paths also have other distinct criteria which distinguish them in objective, verifiable ways (requirements, slope, obstacles, surface, smoothness) which could give a clear distinction in level. Having a different level for such paths raises the sensitivity of taggers to that distinction, whereas adding the wheelchair tag is an extra step that those without exposure to the disabled community may not take. Thus, Value 1 paths which are actually wheelchair accessible may not get that additional tag, and may then not be identified by clients.

The additional complexity in the schema (an extra level with unique criteria) could result in more specific tagging and better utilization of the paths by the disabled community, or conversely a more simple schema could result in great adoption and more useful tagging to a majority of trail users, or (many other possible outcomes). I leave it to the experts to assess those tradeoffs, but I will advocate for inclusion of accessibility considerations.

Agree. NFS Class 5 would probably correlate well with a Level 0 : [Handicap] Accessible trails (but Class 5 isn’t explicitly constructed for accessibility).

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I don’t think the majority of trail users that follow use OSM are going to have instruments to grade incline=8% on the fly. There’s also width to take into account as well though that is simpler. I imagine the incline=8% is for unassisted wheelchair use, higher inclines would be possible with assisted wheelchair use, which would be another value.

I will freely admit that in my normal life I don’t pay as much attention to the signage as people directly impacted do, but I feel like a lot of the times accessible hiking paths (in the US) are clearly marked with a blue sign with a white wheelchair on it and wording like “wheelchair accessible”, which would be a great and obvious time to use the wheelchair=yes key. I’d imagine that since such trails are meant to be accessible they will be maintained to higher standards to ensure they remain so. Having someone mark paths with wheelchair=yes when they see a sign seems potentially safer than having people guess unless there are a lot of hiking paths which are wheelchair accessible but not marked as such.

I would imagine the best bet for any accessible hiking paths that aren’t marked or formally intended as accessible would probably be multi-use or road bike trails. Most informal trails that don’t have a land manager probably aren’t going to be developed. I don’t recall if the gravel carriage roads in Acadia were marked as such, many have higher inclines but fit all other criteria.

I think it’d be good to get some feedback from a11y community as a whole, but hiking paths are far less likely to accessible than footpaths or cycleways, and more likely to be required to be built to be accessible (which generally means they aren’t often in formal wilderness in the US at least) rather than end up being accessible like a sidewalk.

Here video on Austrian scales, English subtitles available, the pictures should be telling - Wandern: Wegeschwierigkeiten verstehen | Sicher Bergwandern | Episode #4 - YouTube - They try to be funny: The guy with the cheese is from Vorarlberg where blue is the hard trail, the guy with the pipe is from Tirol, where blue would be the easy trail, which is marked very rarely though.

Mapping Austrian colour to values above:

  1. blue
  2. red
  3. black
  4. Alpine Route icon

I’m surprised how clean that maps. Maybe I did not read thoroughly enough?

Classification saw some shift in recent years. What was red 30 years ago might be black now. I’d say, that comes from growth in public, in order to adapt to changes in abilities and desires. Alpine route was only introduced recently to make black less open-ended and sort out legal issues. Meanwhile this class has spread to other parts of Austria.

Thanks, I’ll go over it and update. It does map pretty well to a number of systems - it deals with clear “real world” impacts related to the level of technique people need to move over terrain and there’s been a lot of similar thinking. There’s a decent chance someone could use this properly without looking at the wiki which can’t be said for most other systems - while the key values are human movement centered I tried to keep things “verifiable” by focusing on the terrain/obstacles that cause different types of movement.

You’ll recognize the bones of this from your scramble thread, it lives on!

It’s interesting how “casual” ratings tend to be easier than the past, while “technical” ratings keep on getting harder and harder. YDS was supposed to stop at 5.10 because it was the hardest thing a human could climb, and now we’re at 5.15d or whatever. I figure if people want more granularity for scramble they can just add whatever local system they want on there. hiking_technique=scrambling + bmc=3 or sac=t6 or whatever. All that is for nerds and doesn’t need to be in a general rating. :stuck_out_tongue:

I’ve updated the main post, but I’ll copy it here too.

Links to different rating systems

YDS & Bouldering


NFS Trail Classifications (loose and not 100% predictive for higher grades)

SAC & friends






https://www.cai.it/wp-content/uploads/2021/12/allegato-circolare-22_2021-Classificazione-difficoltà.pdf (pdf in Italian)

bielointothewild.com - bielointothewild Resources and Information. (good unofficial write up)


Tasmanian PWS

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CAI (unofficial, couldn’t find anything on the CAI website)

there is docu in the wiki:

on the cai website there is (found it with a search engine, not on the website): https://www.cai.it/wp-content/uploads/2021/12/allegato-circolare-22_2021-Classificazione-difficoltà.pdf

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Thanks, the wiki wasn’t loading for me when I was writing this up. I’ll edit the links up top. I guess it’s not surprising I didn’t pull up a PDF in Italian from my own search results. :slight_smile:

I like the idea very much in general of redesigning what we use as “hiking difficulty”. Still this (on the lower end) for me has the same problem that the current sac_scale has.

For the casual hiker SAC T1 and T2 are too broad, there is a lot of detail within it that we could pull from other tags, but which might also warrant splitting up the values 1 and 2 into further values.

My idea would be something like this (for splitting the Value 1 in your proposal):

Value 1: Easy walking:

Description: The ground is mostly smooth. Very small obstacles might exist, but they are very easily visible, and easily circumnavigated. When walking you need to pay pretty much no attention to the terrain. The path is useable by everyone, including people not that sure of walking and strollers. Might require hiking footwear when the weather is bad.

This would mostly be used on track_type=1 or 2 tracks, or paths that are about NFS class 4 or 5. This is very much on the low end of SAC T1

Value 2: Walking

Description: The ground is slightly rough. There might be some smaller obstacles (bigger rocks within the ground, some overgrowth), but they don’t require a serious effort to circumnavigate. Obstacles aren’t higher than shin height. Keeping a bit of attention to the terrain is important, but taking a look around for a couple of seconds while walking isn’t a problem. Likely not useable by people that are unsure of walking (small toddlers, seniors that require a walking aid), using a stroller is probably not possible. Hiking footwear recommended when the weather is bad.

Typical usage would be track_type=3 or 4, maybe some track_type=5, many smaller forest paths. In NFS classification this is a “wilder” class 4 or a class 3. We are about in the middle of SAC T1.

Value 3: Hiking

Description: The ground is fairly rough. Small obstacles (smaller rocks, overgrowth) appear often/continously and need to navigated. Bigger obstacles up to about knee height might be present, but can still be navigated mostly without stopping to check where to take the next step. Continous attention to the terrain required. Certain amount of surefootedness is required, so smaller children and seniors likely shouldn’t take this path. Terrain might get fairly muddy on bad weather, but hiking gear is recommended in general.

This might get used on some heavily overgrown/low usage tracks with track_type=5. In the NFS system this is class 1-2 with some harder class 3 mixed in. We are still within SAC T1, even though this might start to pass into SAC T2.


Today I learned something about the Austrian classification that I’d like to mention here:

Imagine, you are a tour guide. There are two licenses - hiking guide and mountaineering guide.

A hiking guide may only guide tours on paths classified red at most.

If you want to guide tours over routes classified black, you need a mountaineering guide license.

The difference between red and black is specified: If you trip on a red way and stay completely passive, you fall at most 30 m. It will hurt but it likely will not change your life for the rest of it. Otherwise, it is a black route.

Why not just propose a new key austrian_class=*? We generally use a key containing “scale” for difficulty, but if it is called Austrian Classification, perhaps we should stick with a key related to that.

A scale is what is used for classification :wink: BTW, we already had dav_scale (for the blue/red/black system), even though easy to tag – just copy from the guidepost dot – it languished. If it can be made complicated, why go the easy way?