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

[Andy Townsend]

On 03/01/14 19:56, Fernando Trebien wrote:
> Well, when proposing this, I'm trying to avoid these problems:
> - the set of paved and the set of unpaved surfaces is not closed, and
> so it would require us to continuously update Carto with new surface
> types

I'm a bit confused by what you mean by "carto" here.  The tool itself 
just converts from a CartoCSS stylesheet (such as you can create/edit 
relatively easily with TileMill):

http://wiki.openstreetmap.org/wiki/CartoCSS

The stylesheet used for the OSM standard map is:

https://github.com/gravitystorm/openstreetmap-carto

and for the HOT map is:

https://github.com/hotosm/HDM-CartoCSS

So there isn't just one "Carto" rendering.  Also, there's not likely 
ever going to be "an agreement between everyone" about what sort of 
"suitability for X sort of traffic" is represented on the "standard" 
map.  Personally I'd argue that the whole tracktype / path / footway / 
bridleway rendering area is "too complicated" now for lay users, rather 
than "not complicated enough".  We've already had help questions on the 
lines of "what's that brown stain on the map":

https://help.openstreetmap.org/questions/13521/icon-explanation

So the answer surely has to be different rendered maps for different 
purposes - someone who's creating an MTB map can render the MTB tags, 
someone who's mapping an area where "smoothness" is used in a sane 
manner can map that, etc.  If someone wants to come up with a big 
x-dimensional matrix that combines various tracktype / smoothness / mtb 
/ whatever tags into a numeric value, they can do that too.

The good news is that it's actually easier than ever to do that now as 
osm2pgsql now supports external tag transformations using a lua script:

https://help.openstreetmap.org/questions/28465/osm2pqsql-and-lua

https://github.com/openstreetmap/osm2pgsql/blob/master/README_lua.md

It's so easy that even someone like me (with less design expertise than 
the average three-year-old with a crayon) can do it to render other 
values instead of tracktype without changing the openstreetmap-carto 
stylesheet at all:

https://github.com/SomeoneElseOSM/designation-style

So if you think an extra tag makes sense ("trafficability" or something 
else), start using it locally, create a map using it, and ask people 
what they think.

Similarly, if you think that some numerical combination of existing or 
new tags to create a "new tracktype" would work, create a map using that.

Cheers,

Andy