[Tagging] Proposed definition for surface=cobblestone/sett/paving_stones

[Fernando Trebien]

On Mon, Jan 22, 2018 at 4:14 PM, Martin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> 2018-01-22 17:25 GMT+01:00 Fernando Trebien <fernando.trebien at gmail.com>:
>> - sett: hewn stones with flat top, wide filled gaps, comfortable to
>> cycle and walk on, uncomfortable on high heels [today's image and also
>> [2] used previously for sett]
>
> ok, although it remains unclear what "filled" gaps means. Is this
> purposefully filled (e.g. with sand, or bitumen), or is it about them being
> old? You'll hardly find open gaps in older pavements, because they will fill
> themselves.

I would make no distinction between the two cases. The filling makes
the difference in height between the stones and the gaps less
pronounced, so it produces a smoother surface, especially it is nearly
at the same height as the stones.

>> - cobblestone: hewn stones with slightly arched top, wide filled gaps,
>> uncomfortable to cycle on, difficult on high heels [images [3] and [4]
>> used previously for cobblestone:flattened and cobblestone]
>
> difficult to distinguish from your previous example (sett)

>From the opinions I've found from British and German mappers, I think
the distinction is perhaps almost irrelevant for large vehicles such
as cars, but significant for smaller vehicles such as bicycles, and
also for pedestrians (both those wearing shoes and those wearing high
heels). We can use the images that have already been used as examples
(I think the threshold lies between images 4 and 5):
https://i.imgur.com/HYmjeO6.jpg

We can also try to define it more technically (what does it mean to be
"slightly" arched). Right now, or as a future refinement of the
difference.

But I think we can't escape the issue of borderline cases (that happen
also with other values of surface=*) and this hasn't prevented mappers
from making sensible choices.

>> - cobblestone:raised: natural or hewn stones with very round/irregular
>> top, wide empty gaps, fixed to a bedding, difficult to cycle and walk
>> on, uncomfortable to drive on [images [5] and [6] used previously for
>> cobblestone but rejected]
>
> again "empty gaps", same comment as for filled gaps.
> "uncomfortable" for driving in a car? Depends on the suspension of the car
> I'd say.
> I agree that these seem to occur more rarely than the cobblestone:flattened,
> although around here it is full of them (in old villages / towns).

I'm proposing this because I think, looking at the wiki edit history,
that cobblestone:flattened has caused some confusion depending on what
definition of "cobblestone" a mapper has in mind - the vernacular,
arched, cuboid type [3] or the technical, fully roundish type [4][6].
So, if its usage is low, maybe it's a good idea to get rid of it to
improve clarity overall. It would be a much smaller effort than trying
to make sett and cobblestone adhere to their exact technical
definitions.

-- 
Fernando Trebien
+55 (51) 9962-5409

"Nullius in verba."