Foot=no - prohibited / impossible

Continuing the discussion from Passable vs impassable scrub (or heath):

Well… Key:foot - OpenStreetMap Wiki also has " prohibited or impossible" by another person… Path examples - OpenStreetMap Wiki also gives examples where foot=no is used to mean impassable on foot, etc. Conflicting wiki edits aside, I also seem to recall more than a few discussions from the times pasts on the subject, which all seems to indicate that there seem to different opinions, understandings, and practices.

I’d agree that in vast majority of the cases one would use them to mark legality of such mode of transport.

However, I myself (and I suspect many others) have been known to mark bicycle=no or motorcar=no to mark barriers/passages which are physically impassable by bicycles/motorcars, even if the law did not say anything about that (or at least there were no signs - it is quite possible that some law prohibits citizens from doing physically impossible things, but I haven’t done a deep research on that). IMHO, in such cases, benefits gained by marking them as impassable for such transport mode far outweigh potential slight inaccuracy in definition likely preferred by majority.

Perhaps those were not the best tags (can you suggest better ones which work? I’d love to give more precision!), but it gets the job done - if you are using bicycle/motorcar/... you should not go there. Whether it’s illegal and you’ll get shot by SWAT by attempting to cross there, or it is merely physically impossible to do and you’d fall to your death by trying to venture there, the final message to data consumer is very similar: if your_transport_mode=no, just don’t do it.

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Legal access tags (foot/bicycle/motorcar) are only meant to describe the legal/signposted aspect of the trail/road.

To describe the physical aspect or difficulty of the trail on foot, use instead the official sac_scale tag which is supported by most outdoor end-user applications.

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I wonder, what could that be, a way that is impossible to follow on foot. Why would anybody even map a way there? Pictures available?

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Maybe a footway that was previously passable but is now obstructed in some way? It could make sense to tag it as foot=no rather than delete it completely if it still exists in imagery, especially if the mapper thinks it might be restored in the future.

Using lifecycle tagging along the line of disused:highway=path|footway or abandoned:highway=path|footway would be better if the trail has become impassable.

If still visible on the ground and passible then trail_visibility and/or sac_scale are appropriate tags.

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Thanks, sac_scale does make sense four mountain paths. I’m not sure what sac_scale to use for overgrown vegetation, as Familiarity with the handling of technical mountaineering equipment wouldn’t really help (but machette or chainsaw might). See original post this thread was forked from, and where I did suggest sac_scale for parts that are passable on foot.

I’m also not sure sac_scale would even make sense at all e.g. for a heavy traffic multilane highway=primary where (while legally undefined or even allowed in specific country) it is still certainly suicidal to try to enter on foot?

foot=no may be mapped on an area too, see original thread this discussion was forked off.

For explicit ways, it makes sense mostly only in combination with Conditional restrictions - OpenStreetMap Wiki (e.g. seasonal overgrowth, or mountain snow, or melted lake which has way over it, making a way intermittently impassable) - if it’s become permanently impassable (e.g. due to landslide), it would better for the path to be cut with noexit=yes put on both sides to discourage armchair mappers from reconnecting it from aerial pictures.

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Yes, to be clear I was aiming more at saying “this is why mappers might use this” rather than “this is the best solution”.

There are places (Scotland, Scandinavia and others) where there is a presumed right of access on foot. In other places (England and Wales, and probably others) “whether foot or bicycle access is legally allowed” is entirely separate to “whether foot or bicycle access is actually possible”. For example, there are lots of places in England and Wales where bicycle access is legally allowed but physically impossible, and also lots of places where bicycle access is physically possible and permitted at the consent of the landowner but not a legal right. It’s important to distinguish between those tags in OSM.

Access tags record the legal access rights. Lots of other tags (smoothness, trail_visibility, informal, hazard, etc.) record whether something is suitable for a particular person using a particular mode of transport. I might be happy forcing my way through a hedge or overgrown scrub; other people may not be. There is no “one tag fits all” - setting any tag to say “yes” or “no” would be extremely misleading.

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obstacle=vegetation is handy for this:

“Movement on route is hard due to the vegetation (shubs, dense grass, nettle, lianas etc.), movement is significantly slowed down or you have to move carefully.”

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I was informed by an employee that the Ordnance Survey (British national mapping agency) deliberately do not show some public footpaths because the legal route crosses very dangerous terrain, such as a cliff.

In the course of mapping paths on OSM I’ve have come across impassable paths: normally I report these to the local highway authority who then send someone out to clear vegetation or other obstacles.

I think that’d be an example where there might be a legal right of way but there isn’t actually a path - in that circumstance I’d just not use a highway tag (or if appropriate, use one with a lifecycle prefix). There are a couple of examples here, which you can see by turning on the “LA PRoW” layer. There’s no actual path from the middle of that map to the southeast, or extending from the stub in the northeast to the southwest, but there is (legally) a public right of way. You’d need to climb a couple of cliffs into and out of a river valley and through some bracken in one case, and across a substantial fence in the other!

Interestingly, the OS do show (on both Landranger and Explorer scales, it seems), the path across Morecambe Bay that is visible on the LA PRoW layer here, as can be seen here (turn on the “Ordnance Survey” layer to see it). The OS use a specific written caveat at both ends; OSM doesn’t show it.

Long highway=trunk tunnel without sidewalk or shoulder where legal status of pedestrian access is unclear but if you go inside then it will definitely end with dead pedestrian

trickier case is where you may be legally allowed to go somewhere but you are very likely to die if you actually try (high speed highway=trunk tunnel without sidewalk or shoulder)

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But aren’t they distinguishable? Former is (in my mind) bicycle=no (because Physics law trumps England law, i.e. it is irrelevant what England law allows if it is physically impossible, as nobody will be able to do it in either case), and latter is bicycle=permissive. Do you think they need some extra distinguishing?

It is mapped in OSM (Way: ‪Cross Bay Walk‬ (‪858076462‬) | OpenStreetMap) but isn’t shown because a lifecycle tag (disused:highway) has been added to the way. I’m not really sure it’s technically correct to use this tag in such a way, but it is such a dangerous route, that it seems sensible.

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In my mind, that does not make it impossible. It makes doing so dangerous. I strongly advocate to not mix these terms and make a conundrum out of simple tags with a concise meaning.

I thought you Britons have highway=no to map such?

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I agree with that. Giving a single tag two different definitions makes it useless imho.

If foot=no is defined as “legal access by foot is prohibited” the meaning is clear to everyone.

If foot=no gets the additional definition “impossible to pass here by foot” no one can be sure about the situation OTG, especially because “impossible to pass” may be very difficult to evaluate and may change from season to season to add some more complexity. A path or area which one person might evaluate as “impossible to pass” may be seen by another person as “difficult, but not a real problem to pass”.

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When I started mapping sidewalks, I did so mostly to map, when there was no sidewalk, where one would be expected. Until, when I noticed, that routers shied from highway=primary in their pedestrian profile, when no sidewalk was mapped. Then I began to map the presence of sidewalks too :slight_smile:

Note that it is not about adding additional definition: that particular cat has been out of the bag for more than a year and a half now even if we look just at latest wiki change (and even much before that, people seem to have been using it ambiguously).

I’m more about documenting the current situation. It makes no sense to pretend that this tag is not being used in a way that some people dislike. IMHO such behaviour should be documented (and perhaps discouraged, if that is the consensus), but not swiped under the rug - so data consumers can take that peculiarity into the account.