[Poll / Follow-up] How to tag MTB rideability when difficulty is unknown?

[aktiivimallikansalainen]

@Tolstoi21

But notice that we’d have to have similar tags for at least bicycle:scale=*, foot:scale=* and hiking:scale=*. We need all the different modes to be present as none of these passable values for the different modes are immediately and truth-preservingly inferable from each other.

The existing mtb:scale with values between 0-6 is quite succesful, so if someone wants to copy the idea for any other mode of transportation then I guess they can. And I guess that was part of the proposal in the first message, that this would be extendable to any mode of transportation that uses difficulty based tagging.

(As an aside I’ll note that Trailmap has shown that just mtb:scale is usefully descriptive for hikers, geocachers, trailrunners etc. at least in typical Finnish wilderness conditions.)

@Tolstoi21

Like I said, at this point, were simply duplicating a few descriptive tags with a needlessly contrived, somewhat subjective (as @tekim noted) and mode-specific tagging system.

The specific situation where more accurate/objective tags cannot be applied has already been addressed at least a few times in this thread.

This looks like an argument against any :scale like tagset as a whole. You are welcome to the opinion, but I don’t think this is the place. And like I mentioned above, mtb:scale is a very succesful tag, it has renderer support and provides value to end users.

[Tolstoi21]

@aktiivimallikansalainen

This looks like an argument against any :scale like tagset as a whole.

Sorry, my quote above was imprecise. I’m not arguing against a :scale. Indeed I agree with you that the 0--6 gradation in mtb:scale is very useful!

My arguments above were specifically against a catch-all value of passable instead of the informative and specified gradations.

[rhhs (Richard)]

@Tolstoi21

My arguments above were specifically against a catch-all value of passable instead of the informative and specified gradations.

The proposed new “passable” and "impassable values for mtb:scale=* should not be seen as permanent values, but as temporary values to help improve tagging of ways for MTB use. They should function as a stepping stone from no tag at all towards a value from 0-6, and away from bicycle=yes/no. There are many mappers who want to express that they think a way is impassable for bicycles and should not be including in routing for bicycles. We should offer them an alternative for tagging the way with bicycle=no, which is wrong when there is no legal restriction and is likely to not be corrected quickly because it needs local knowledge to be able to do so. If tagged with mtb:scale=impassable (unknown, … TBD), it it tells a mountainbiker map user that the way is probably difficult, but still lacks information on if it is passable by him. More importantly, it tells that the way needs survey by someone with some experience in mtb riding to determine how difficult it really is. It should be highlighted as an issue by OSM quality tools, field survey apps like Vespucci, and hopefully also by map apps used by mountainbikers. I think this would stimulate the mapping of mtb:scale=*

[julcnx]

@rhhs

The proposed new “passable” and "impassable values for mtb:scale=* should not be seen as permanent values, but as temporary values to help improve tagging of ways for MTB use.

Right, but I’d avoid using the term “temporary” — it tends to scare people off, since we’re not supposed to map truly temporary features in OSM. A better way to frame it might be as a provisional “placeholder” — like how we use general =yes and other tag values (e.g. building=yes, surface=unpaved, or highway=road) as placeholders that can be refined later with more accurate data.

@rhhs

If tagged with mtb:scale=impassable (unknown, … TBD), it it tells a mountainbiker map user that the way is probably difficult, but still lacks information on if it is passable by him.

But that means a way tagged like this could be almost anything. At least with mtb:scale=passable, we’re providing some objective information. “Probably impassable” feels more like a subjective interpretation — similar to calling something “impractical” vs. “practical” — which isn’t very helpful anymore in my opinion.

As @aktiivimallikansalainen pointed out, routers could already avoid routing over uncertain paths by using elevation data and other existing tags when mtb:scale is missing.