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

[malenki]

Am Tue, 31 Dec 2013 14:10:33 -0200
schrieb Fernando Trebien <fernando.trebien at gmail.com>:

> [rendering unpaved roads]
> The Brazilian community has shown interest on this many times,
> since lack of this feature causes unaware users to classify roads
> incorrectly. 

There are a lot of countries which would have an advantage of such a
style.

> David Bannon proposes (below) that we use the tracktype
> tag for that instead, but I've never seen it being used for anything
> besides roads with highway=track (therefore, not a very common
> practice it seems). 

Some examples have been mentioned in the other replies; I would like to
add the 
* Baltic States (which have big woods with tiny settlements
  sprinkled in them being connected with unpaved roads)
* Poland with some regions alike the above mentioned
* Albania which is still struggling to pave its major roads, not to
  mention the minor ones. An example is the SH4¹ which was unpaved in
  big parts back in 2011 but well travelled. It is a primary highway
  with tendency to motorway
* Australia is already mentioned in the mail you forward and I assume
  that in
* Africa a lot of roads are similar 

> Do you think we should encourage its use in
> conjunction with unclassified, tertiary, secondary and primary
> highways?

yes

> It seems to me that surface=compacted is quite similar in meaning to
> tracktype=grade1 (whereas surface=sand, surface=dirt, and others,
> could be equated with other grades but rarely with grade1,
> particularly because the "compacted" value exists) and so both tags
> could be used for the same rendering purpose. Do you agree?

I wouldn't connect surface=compacted and tracktype=grade1 per default
since compacted roads and and roads with really paved surface (asphalt
or cobblestones) are not unlikely to show a very different driving
experience after some good rain.
Of course this also depends on your definition of "compacted". :)

For rendering a map displaying highway quality beside their
classification I'd consider useful not only the tags
* surface and
* tracktype 
but also
* 4wd_only (maybe mentioned at the Australian Tagging Guidelines)
* ford= 
and some thoughts on roads in dry riverbeds. So far I mapped them with
ford=yes. Iirc there have been discussions about this topic but at
the moment I don't have time to research them.
Once I also used ride_height=[value] because one road I walked would
have required a car with about 40 cm ground clearance to pass it.

looking forward to that enhanced rendering style,
Thomas

¹ http://www.malenki.ch/Touren/11/Galerie/Tag_22/slide_34.html
( contains exif tags with valid geotagging)