[Tagging] Tags useful for rendering of roads in poor conditions

Thu Jan 2 01:25:06 UTC 2014

I want to add my opinion on this topic before you make a decision. Where I
do most of my mapping, the United States and Thailand, most roads are
paved. The assumption therefore is that in the absence of a surface tag,
the road is considered paved and rendered according to one of several
schemes (which shouldn't concern us here, correct?). From the discussion
I'm afraid you will want to make unpaved the default which I think would be
a mistake.

Furthermore, the majority of my mapping in Thailand is done from Bing
imagery. One cannot state for certain whether a road is paved or not that
way but in the general case the assumption of paved would be correct. All
this discussion and opinions about track types is relevant if you're
working on the ground in an area with which you're familiar but the game
changes when you're trying to add highways in distant rural areas where the
only information available is from aerial photographs.

This discussion has merit and is interesting -- I will continue to follow
it to see where it all leads.

Regards,

Dave Swarthout (AlaskaDave)

On Thu, Jan 2, 2014 at 7:57 AM, Fernando Trebien <fernando.trebien at gmail.com
> wrote:

> Welcome, David. If you've just been advised about this discussion, you
> may wish to read it from the start:
>
> http://gis.19327.n5.nabble.com/Tags-useful-for-rendering-of-roads-in-poor-conditions-td5791303.html
>
> Like you, I'm concerned about road safety. I'm concerned about making
> the visual map better for visual routing. And I'm also concerned about
> unaware users who have been classifying roads as highway=track simply
> because they are unpaved (managing that in Brazil has been a bit
> problematic). The latter has given us some headaches here in Brazil.
>
> I'll try to summarise: I'm pretty much open to using either the
> surface or the tracktype tag, I'm just trying to figure out which
> approach is most popular for this purpose. Different people have
> advertised either approach, and both have problems of their own. The
> surface tag may range from very specific (say, paving_stones:30) to
> very imprecise (simply unpaved), and there are many values to be
> handled (but I just provided a reasonably comprehensive list). The
> tracktype tag has fewer values but (as Matthijs pointed out) some less
> obvious semantics that requires checking the wiki frequently. To make
> tracktype popular with highways that are not highway=track, I believe
> we'd need to request JOSM's developers to add a tracktype field to
> many presets, so it's extra trouble.
>
> Like Matthijs, I've been leaning towards a combined approach that
> would take both tags into account, so that different OSM communities
> can choose what they prefer. It's no doubt that tracktype=grade1 can
> be considered "paved" (for rendering) and any other tracktypes can't.
> But in the absence of that tag, we can then use the surface tag to
> decide.
>
> From other discussions, I've learned that the tracktype tag appeared
> originally in the German community and it was originally intended only
> for combined use with highway=track. Then, in Anglophone countries it
> was understood that "track" in tracktype could refer to many highway
> types, as they are all types of "tracks" (in actual English, not in
> OSM tag lingo).
>
> Rendering details is not the purpose of this list, I believe we're
> discussing which tags are more meaningful to end users for
> establishing a clear separation between paved-like and unpaved-like
> ways. Briefly mentioning: Malenki has suggested grainy rendering for
> "unpaved" ways, and Matthijs, a dashed outline. I think Matthijs'
> suggestion may display more clearly. Malenki has also suggested a red
> outline for 4wd_only ways and a blue outline for ways that go through
> water (ford=yes). The latter two make a lot of sense to me. I'm not
> sure we're gonna push them along with the "unpaved" style, but I
> wouldn't oppose them either. But again, visual style is not to be
> discussed here; perhaps the "design" list is a better place for that.
>
> On Wed, Jan 1, 2014 at 10:07 PM, David Bannon <dbannon at internode.on.net>
> wrote:
> > Hello Fernando, I was just advised about this mailing list so have
> > joined yet another ! (sigh...)
> >
> > Thanks for pushing this issue, my concern is that people's lives are
> > potentially at risk here.
> >
> > While I am not really committed to using tracktype= as the trigger, on
> > the Austrialian mailing list we had a long discussion about it and, more
> > or less, concluded it was the best option from a poor set.
> >
> > The options were summarised on
> > http://wiki.openstreetmap.org/wiki/User:Davo
> >
> > and in the Discussion section, you will see that I quoted some numbers,
> > dating back to late 2012 showing that there are twice as many tracktype=
> > tags used as surface=unpaved.  I think the biggest problem with surface=
> > is that it has so many possible values.
> >
> > The original approved definition of tracktype made it clear it could be
> > used where highway= other than 'track' and it is widely so used but I'd
> > have to download all the data again to get fresh numbers on that.
> >
> > I wanted to extend tracktype= to three further values representing 4x4
> > only roads. But could not get a committment from enough people to get a
> > vote going.
> >
> > But, all that aside, the real need is to see unsealed roads rendered in
> > such a way that people are warned and not put in danger. I would be
> > happy to support and sensible trigger tag. Except, perhaps, smoothness=,
> > I will not describe the pretty little road I live on as "horrible" !
> >
> > David
> >
>
>
>
> --
> 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)
>
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-- 
Dave Swarthout
Homer, Alaska
Chiang Mai, Thailand
Travel Blog at http://dswarthout.blogspot.com
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