[Tagging] Narrowing the application range of the smoothness tags

Stefan Tauner stefan.tauner at gmx.at
Wed Jan 27 22:24:09 UTC 2021

On Wed, 27 Jan 2021 09:29:02 +0000 (UTC)
Richard Smits via Tagging <tagging at openstreetmap.org> wrote:

> @Stefan I hope you agree that putting the more detailedexplanations
> in an additional table column makes it clearer?

Yes, good work! Sorry for what again became a quite elaborate email :/

> If necessary,
> evenmore details could be put in a separate page, like this one
> https://wiki.openstreetmap.org/wiki/Berlin/Verkehrswende/smoothness

I think having this matrix with example pics for all kinds of different
surface types would actually improve the uniformity of tagging in
comparison to your table suggestion. I think most mappers would have a
much easier time comparing a situation to a picture than to a
description in prose form. The latter leaves many things to imagination
and interpretation. The matrix relies a lot on finding good photos and
of course is more work though (and there are quite some surface types
that are not covered there yet...).
One thing I don't like about that page is that the vehicle row is
described as "problemlos/ideal for vehicle x" == trouble-free/ideal for
x". This might not fully translate to English but there is a big
bandwidth between being able to use some option on a surface without
severe problems and thinking some surface is ideal for option x. Also,
pretty much every option would gain something from a better category. I
definitely cycle more smoothly on an excellent, good or even
intermediate street than on a very bad one (IMHO that's obvious but
since you gave the example and I noticed it I had to say something :)

> I don’t see why we should have an even higher tier of smoothness
> (“perfect”, maybe?) above that of “excellent”(near-perfect) because
> even for rollers that wouldn’t make much difference inpractice.

Well, one can definitely measure and feel a difference between different
types/smoothness even of *newly* built streets with the right tires,
e.g., roller skates or sufficiently pressurized bicycle tires (>=6 bar).
For example, there is a noticeable gradient of smoothness on a big
boulevard in Vienna[1] that is very seldom used by cars (only in
emergencies and for some events like marathons) and thus in a
relatively good and uniform shape overall. On the outermost ~25cm on
each side there is nevertheless much less wear because people, bicycles
and carriages avoid that part. The difference on a normal trekking big
is very noticeable but optically it does not stand out at all. If you
look hard at the full-resolution 4k picture it is even visible but
probably only because you know where to look :)

There are also some cases of marble stone/tiles that are even a lot
smoother than common new asphalt. There, inline skates might even have a
hard time with the wrong rollers on because they might slip. But that's
rather of limited importance for routers since that's almost
exclusively in very dense places or indoors.

From a practical router implementation standpoint or as rationale to add
something like "perfect" I would argue that it makes sense to give a
router for inline skates/thin_rollers a way to distinguish a route that
is OK/works well and one that has objectively a better surface for the
purpose and thus one might prefer even if it is a bit longer. With a
single category deemed "usable by" thin rollers this option does not
exist - one can only give the less viable options a bigger penalty.

There are some objects with smoothness=perfect, cycleway:smoothness and
cycleway:right:smoothness (and it wasnt me! ;) and even some uses of
surface=perfect which is obviously an error. For smoothness there exist
a lot of other (rarely used) values that are more often used, e.g.,
execellent (sic!).

I also just noticed that some people can't decide and use
good;excellent or excellent;good. We should either define the "correct"
order or discourage that completely IMHO.

1: https://de.wikipedia.org/wiki/Hauptallee_(Wien)#/media/Datei:Hauptallee_printempe.jpg
Kind regards/Mit freundlichen Grüßen, Stefan Tauner

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