[Tagging] paved=yes/no

Tobias Knerr osm at tobias-knerr.de
Sat Jul 17 17:42:02 BST 2010


On 2010-07-16 at 06:50, Steve Bennett wrote:
> On Fri, Jul 16, 2010 at 8:43 AM, John Smith <deltafoxtrot256 at gmail.com> wrote:
>> That was what I was trying to figure out, is there a good reason for
>> such a tag, or is it going to just confuse people.
> 
> IMHO yes it's useful, because the paved/unpaved distinction is by far
> the most important one for roads. The problem is that surface=* is an
> unbounded list, so renderers potentially have to support surface=dirt,
> gravel, cobblestone, mud, cracked_concrete, rough, and whatever else
> peoples' fertile imaginations come up with.

So what if my application distinguishes between continuous paving
(asphalt, concrete, ...), tiled paving (paving_stones, cobblestone,
grass_paver, ...), and unpaved? Should I invent another tag like
"paving=continuous/tiled/none"?

While the list of surface values is *potentially* unbounded, it is
finite at any given time. For practical purposes, just teach that list
of surface values on the wiki to your renderer, do a quick tagwatch
check to find out whether there is some other really common value and
ignore the rest.

Most mappers tend to stick to well-known values anyway. (That's even
more true for the increasing number of editor preset users.) If you
write an application or rendering style, don't worry too much about
mappers sabotaging your style by inventing a new surface value for every
road. You see, mappers actually want their data to be useful.

Tobias Knerr




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