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"bicycle=no" is meant to indicate that bikes are forbidden. So how do you tag a walking track that is technically not forbidden to bikes, but it's just completely impractical: narrow, steps, tree roots, rocks, gaps etc. I'm tempted to just tag it bicycle=no anyway, but thought I'd check.

The reason I want to tag this is for a state park where there's lots of great firetrail and singletrack for mountain biking, but some paths will just end in misery if you attempt them.

asked 09 Jul '11, 08:41

Stevage's gravatar image

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The tag mtb_scale might be of some value for this purpose.

This is based on the Single Trail Scale system. Scales like this ,and the SAC Scale for walking, have been developed to maximise use of objective criteria, but use within OSM is often still subjective and inconsistent.

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answered 09 Jul '11, 09:52

SK53's gravatar image

SK53 ♦
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edited 09 Jul '11, 10:09

Jonathan%20Bennett's gravatar image

Jonathan Ben...


Thanks - I did consider that, but there are some downsides. For starters, the mere fact of setting a MTB difficulty level implies that it's suitable for MTB. Secondly, because of the precision of the system, if I set a tag like mtb:scale=6 for the whole path, the tag is inaccurate for the rideable (but dead-end) singletrack sections. I almost want a tag that just says "mtb: don't bother". Maybe mtb=no?

(09 Jul '11, 10:13) Stevage

re: "if I set a tag like mtb:scale=6 for the whole path, the tag is inaccurate for the rideable (but dead-end) singletrack sections"

Isn't that just a special case of needing different tagging for different parts of a way - i.e. split the way at the point the way changes, tag the non-rideable sections with mtb:scale=6, and the rideable sections with the appropriate tags?

(09 Jul '11, 15:46) banoffee

Yeah, but I'll rarely (if ever) have information that detailed. All I want to do is mark an entire path (eg 5km) as either "yes, take your mountain bike down this" or "no, steer clear". Telling people that there are 8 sections of approximately 50m each that are rideable out of a 5km long path isn't especially helpful :) Also, I don't think there's any software that could make use of such information.

(11 Jul '11, 14:31) Stevage

@Stevage: If you don't feel like tagging every section separately, it's perfectly acceptable to mark the entire path as mtb:scale=5 or 6. It's up to you how much effort you feel makes sense (and want to expend). mtb:scale=5/6 is the equivalent of saying "steer clear" - the Wiki explicitly says (about 5):"Very few Mountainbikers can actually ride at this level. Most will have to push." As to software: that's not your problem :-). At any rate, mtb:scale is documented, so software support can be added.

(13 Jul '11, 01:36) sleske

Ok, it sounds like that's the best atm - but it's not great, IMHO. For starters, I think there's a big difference between a real "extreme mountain bike trials" path, and simply a walking track that's not suitable for mountain biking. If I was into mountain bike trials, I'd be pretty disappointed if I made an excursion to visit a track marked mtb:scale=6, only to find that it was just a set of stairs, or unsuitable in some other way (ie, dangerous, unpleasant, discouraged...)

I might see if people are interested in a mtb=walk or mtb=unsuitable tag or something a bit more explicit.

(13 Jul '11, 02:56) Stevage

I've seen the this suggested before, setting a high level of difficulty for trails that are just no fun to bike. I think it is a poor suggestion, as there is a big difference between something that is just not designed for bikes, and is unridable, and something that is designed to be extremely challenging for bikes, like a World Cup downhill race. Setting the MTB:scale to a high value for the former is just inaccurate.

I like both the mtb=walk or mtb=unsuitable tags. There is also the bicycle=dismount access tag, which is not entirely accurate here, as it should be used to represent places where it is riding the bike is forbidden, not just impractical, but it seems to be more accurate than using the mtb:scale tag.

(13 Apr '17, 19:34) keithonearth
showing 5 of 6 show 1 more comments

I guess I should also mention the existence of smoothness=impassable, but that's a pretty flawed tagging scheme.

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answered 13 Jul '11, 03:07

Stevage's gravatar image

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Trawling through related links, I see there's also a set of documented keys like class:bicycle:... that appears to allow for documenting of the kind of subjective opinion of the suitability of the trail that you appear to be seeking?

Edit [after first comments]: On further reflection, I see that you mentioned "steps" as being one reason that it's unsuitable for bikes. tagging those properly (highway=steps) if they're not already would surely act as a strong enough discouragement on its own for anyone thinking of riding a bike there... especially if the smoothness, surface, etc. of the other sections of that path aren't that great.

In terms of detail of which secondary keys to use before resorting to class:bicycle, I really have to defer to more experienced mappers. However, there seems to be a good list of keys that routing software for bikes should take into account at a later section of the class:bicycle page, which should allow for ample scope for describing differences between the surface, etc. of the "nice" paths compared to the "nasty" ones.

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answered 13 Jul '11, 03:25

banoffee's gravatar image

accept rate: 23%

edited 13 Jul '11, 11:21

Yeah, that has the same issue, that even -3 is presumed to be perfectly cyclable - just very undesirable. I've taken my bike through some pretty bike-hostile environments and I can tell you it goes much worse than -3 :) What would you call having to dismantle your bike and scramble uphill through thick scrub with pieces of bike over your shoulder, in multiple trips?

Also note, class:bicycle applies to "Any way or relation suitable for cycling"

(13 Jul '11, 03:38) Stevage

Looking at how class:bicycle is described, I think you may be misunderstanding the scale. AIUI -1 is already something that is unusually undesirable (to be worth tagging with this subjective tag even despite any hints from the other tags), -2 is pretty much telling the router to only use the path if it's the only usable route, and -3 to avoid it completely.

If there are nice +1 or +2 tracks in the area, only a masochist would choose to go along a -1, and certainly not a -2.

Also the class:bicycle:mtb assumes you've already done mtb:scale, so they already know it's not "perfectly cyclable".

(13 Jul '11, 04:02) banoffee

Cough: highway=steps ; ramp:bicycle=yes ; ramp:wheelchair=no does exist. Map the way and the granularity of the survey I'm not sure of granularity measures but smoothness=(nasty enough) and smoothness:granularity=[4800/5000 m ] or a note would explain to humans who really investigate horribleness routes.

(22 Jun '18, 08:17) samuelrussell

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question asked: 09 Jul '11, 08:41

question was seen: 7,928 times

last updated: 22 Jun '18, 08:21

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum