[talk-au] Tagging dirt and 4x4 roads - new approach

Matt White mattwhite at iinet.com.au
Sun Nov 25 02:39:35 GMT 2012

I missed most of this discussion - been away on holidays - so I'm 
getting in a bit late

Anyway, some thoughts:

* Firstly, David, I appreciate the effort in trying to unify the 
4wd/surface/tracktype tag set to make it a little more coherent

* The track type and smoothness tags are in my opinion useless tags. 
What kind of surface do I expect if the smoothness is "very bad" and the 
tracktype of "grade4"? Both are very subjective, and the smoothness tag 
in particular is a terrible set of options. The track type page even 
says it is really only for rough classification.

* The surface tag I can, in principle, get behind, although I think it 
is missing a few values that would be useful in Australia. However...

* Unpaved roads are difficult to really classify the surface in terms of 
anything other than dirt/sand/rock. The surface state changes over time 
from smooth immediately after grading, to possibly deep 
ruts/corrugations/mud after rain and wear. In this case, my personal 
opinion would be to use some sort of tag like surface condition (options 
being something like: maintained | uneven | degraded | corrugated | 
rocky | rutted | deep_rutted, but even those change immediately after 
track maintenance), with perhaps a best/worst case tag or similar

* One area of 4WD/dirt road tagging not discussed (unless I missed it) 
was inclines. Some sections of the bush tracks in AU are very steep, and 
the only way up then is in low range. Knowing that there are 
particularly steep sections of a road visually on a map is also pretty 

* Seasonal closures still don't seem to be cleanly supported (there's a 
dry weather only tag, but that is both subjective, and different to 
gated public roads that are closed between June and October)

* Overall, it seems like Australia has both the special conditions 
requiring some extensions to the current 4WD/dirt road mapping data and 
the active mapping community to back it up. I don't see why we shouldn' 
agree on a handful of tagging rules for the AU conditions on this list 
and use them (assuming that they are well thought out etc). Document 
them nicely so the rest of the world can take them up, and make the 
rendering changes etc ourselves (how hard can a casing change be in the 
renderer? If we can do it an submit it to the trac system...)

On a slightly tangential note, I've even managed to find a paved road 
with a legal access restriction to 4WD only vehicles... in Italy of all 
places. Access to the lower part of the town of Torno on Lake Como (just 
north of Como itself) is restricted to residents with a specific permit, 
and to 4WD vehicles only. The reason for this is that about 120 metres 
of the road (which ordinarily is pedestrian only) is steps (not huge 
steps, but about 150 steps nevertheless). There were also width 
restrictions - a Fiat Panda 4x4 would just squeeze between some of the 
buildings provided you folded in the wing mirrors... (here's the road 
- there's no street view, but there's a panoramio photo)


On 24/11/2012 3:59 PM, David Bannon wrote:
> OK, time I decided we don't really have any prospect of changing
> approved tags to address the dirt road situation.
> So I will push a model, sort of supported by the three votes recorded (!
> ). It will use existing tags (approved and unapproved) and accept that
> maps such as OSM's are unlikely to ever show the results. On the other
> hand, perhaps external projects will make better use of the data ?
> Li Xia, I believe you have plans to use this sort of data, might be good
> idea to confirm this works for you. (I have answered your two off list
> messages but wonder if you got my answers ?)
> I will push the idea that -
> * All unsealed roads should have a tracktype tag and a surface=unpaved
> tag.
> * 4wd roads should have a 4wd_only tag and a tracktype tag. Maybe even a
> smoothness tag if you like.
> * We will ask the mainstream renderers to observe the above tags.
> * Routers will be advised to note above.
> I have update the Australian Tagging Guidelines page and add some data
> to discussion tab. Particularly some numbers about current usage. And
> why tags starting with a digit are a bad idea.
> David

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