[Tagging] surface=ground/dirt/earth

Thu Mar 20 03:03:42 UTC 2014

I just read (almost) the entire thread about smoothness Fernando mentioned
here
http://wiki.openstreetmap.org/wiki/Talk:Accepted_features/Smoothness#Renaming_current_valuesand
I must say, it looks like an uphill battle to make substantial changes
in any definition of a road's usability for routing purposes. I reckon we
all agree that several tags are necessary to fully characterize a highway.
Furthermore, the choice of any of those tags will require some degree of
subjective assessment by the mapper — that's because people are different,
road conditions vary by country, even to the point of saying a primary
highway paved with asphalt in the U.S. is generally superior to the same
sort of road here in Thailand. Can smoothness be "excellent" in both cases
when the best highways in the U.S. are "smooth as glass" while the Thai
counterparts are slightly less than that? (More entirely subjective
wanderings can follow here...) It all depends on who's talking and what
their experiences are in their own locality.

IMO, we must use all the tags we've been discussing to describe a given
highway whenever possible. The definitions for tracktype grades might be
fine tuned to include the concept of durability, especially as regards
weather resistance, and it should be somehow said up front that the various
grades represent a scale of usability by wheeled vehicles with grade1 at
the top. Maybe that's obvious but it should be said nevertheless. All these
(subjectively determined) characteristics occupy positions on a continuum —
there is no "right" choice.

It might also simplify things if we were to somehow rate
their usability for bicycles and roller blades separately or at least with
additional tags. Although I like the smoothness
<http://wiki.openstreetmap.org/wiki/Key:smoothness#Smoothness>definitions
using wheels as a guide trying to define usability for such a wide range of
purposes with the same set of tags is perhaps expecting too much. Using an
mtb_scale or sac_scale tag could extend the characterization when needed as
the examples indicate.

Getting back to your question. I would say, it all depends. When I first
read it, I thought of a stone road, sort of like a walkway, that is, flat,
smooth stones set in a sand base. Such a "track" might be very smooth. But
if you're referring to "crushed stone" (like railroad ballast) the
situation could be quite different. We need more detailed information so we
can employ more tags in such situations. That said, I would not know how to
tag a stone road like I just described. While surface=stone and
smoothness=good would work, none of the tracktypes fit well. If you're
describing a road that runs over a stretch of natural stone, say in a
mountain pass, then tracktype comes into play again.

I assume what we're looking for is a way to assign an overall value to the
highway so a routing engine can make correct decisions. In looking at our
"standard" surface tags for highways, I'm thinking now that they don't
actually tell us much. The tags surface=asphalt, surface=concrete,
surface=paved all bring certain characteristics to my mind, different ones
to yours possibly, but they are actually useless for making routing
decisions.

It appears to me then that we should be looking for is a way to standardize
the smoothness and tracktype tags so a combined numerical value can be
manipulated within a routing algorithm. Let's forget about surface
composition and concentrate on those other tags...

I don't know where to go from here. Anyone else?

Cheers,
AlaskaDave

On Thu, Mar 20, 2014 at 6:16 AM, Fernando Trebien <
fernando.trebien at gmail.com> wrote:

> I think that adding the idea of "risk of degradation" is very
> enriching to the article.
>
> Just to test the concept: if tracktype means durability/endurance more
> than firmness, what tracktype would you (and others) expect to see
> alongside with surface=stone?
>
> On Tue, Mar 18, 2014 at 2:14 AM, Dave Swarthout <daveswarthout at gmail.com>
> wrote:
> > Yes, I agree firmness works better than stiffness for describing a
> surface.
> > I still would prefer a term that better characterizes what Fernando said
> > above: "To me, the idea [of] a firm/soft mixture seems closely related to
> > "how well maintained" the track/road is, as mixtures that are not so
> > durable/steady/firm quickly wear down and look 'poorly maintained'."
> >
> > A poorly maintained road, or one that is not well engineered, or one
> > composed of loose, uncompacted materials will be much less durable than
> one
> > that has those characteristics. Consequently, I still think durability
> fits
> > the bill. I hesitate to bring this up but the discussion about
> > trafficability tried to rationalize the relationship between a highway's
> > surface, hardness, composition and smoothness and ran into similar
> problems
> > (David Bannon?)
> >
> > FWIW, borrowing again from Fernando above I would reword the definitions
> as
> > so:
> >
> > grade1: "heavily compacted hardcore"
> > grade1: [Usually paved. If unpaved then a heavily compacted mixture of
> > materials (gravel, sand, earth, clay) that provide a fairly smooth,
> durable
> > and relatively weather-resistant surface.]
> >
> > grade2: "unpaved (...) surface of gravel [a hard material] mixed with
> > varying amount of [soft materials] sand, silt and clay"
> > grade2: [Unpaved (...) surface of gravel mixed with a varying amount of
> > other materials and lightly compacted or rolled to provide a good
> surface.
> > Less durable or weather resistant than a grade1 track.]
> >
> > grade3: "even mixture of hard and soft materials"
> > grade3" [Almost always an unpaved dirt road. A mixture of uncompacted
> hard
> > and soft materials providing a reasonable surface. Subject to moderate
> > degradation in bad weather. ]
> > grade4: "prominently with soil/sand/grass [soft materials], but with some
> > hard materials"
> > grade4: [A rougher unpaved dirt road with a mostly soft surface, poorly
> > maintained and not very durable. Rain and other bad weather degrade this
> > type of track rapidly.]
> > grade5: "lacking hard materials"
> > grade5: [A very rough unpaved track composed of loose, uncompacted, soft
> > materials often having a surface of grass and dirt, or, in wet weather,
> mud.
> > Not very durable -- easily eroded.]
> >
> > Other OSMers have amended this list to include grade6 and even grade7 for
> > tracks passable by 4WD or ATV only. What about those?
> >
> >
> >
> > On Tue, Mar 18, 2014 at 8:57 AM, Fernando Trebien
> > <fernando.trebien at gmail.com> wrote:
> >>
> >> "Firmness" sounds good to me:
> >> http://www.merriam-webster.com/dictionary/firmness
> >>
> >> I know that "soundness" means the same but has some additional
> >> meanings (http://www.merriam-webster.com/dictionary/soundness),
> >> "firmness" is more specific.
> >>
> >> On Mon, Mar 17, 2014 at 9:09 PM, johnw <johnw at mac.com> wrote:
> >> >
> >> >
> >> >
> >> > On Mar 18, 2014, at 1:35 AM, Fernando Trebien
> >> > <fernando.trebien at gmail.com>
> >> > wrote:
> >> >
> >> >  Replacing 'stiffness'
> >> > with something else is absolutely fine with me.
> >> >
> >> >
> >> >
> >> > What about firmness? soundness?
> >> >
> >> >
> >> > Javbw
> >> >
> >> > _______________________________________________
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> >> >
> >>
> >>
> >>
> >> --
> >> Fernando Trebien
> >> +55 (51) 9962-5409
> >>
> >> "The speed of computer chips doubles every 18 months." (Moore's law)
> >> "The speed of software halves every 18 months." (Gates' law)
> >>
> >> _______________________________________________
> >> Tagging mailing list
> >> Tagging at openstreetmap.org
> >> https://lists.openstreetmap.org/listinfo/tagging
> >
> >
> >
> >
> > --
> > Dave Swarthout
> > Homer, Alaska
> > Chiang Mai, Thailand
> > Travel Blog at http://dswarthout.blogspot.com
> >
> > _______________________________________________
> > Tagging mailing list
> > Tagging at openstreetmap.org
> > https://lists.openstreetmap.org/listinfo/tagging
> >
>
>
>
> --
> Fernando Trebien
> +55 (51) 9962-5409
>
> "The speed of computer chips doubles every 18 months." (Moore's law)
> "The speed of software halves every 18 months." (Gates' law)
>

-- 
Dave Swarthout
Homer, Alaska
Chiang Mai, Thailand
Travel Blog at http://dswarthout.blogspot.com
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