[Tagging] surface=gravel problems

Robert Skedgell rob at hubris.org.uk
Sat Apr 17 06:24:07 UTC 2021

On 16/04/2021 22:15, Adam Franco wrote:
> On Fri, Apr 16, 2021 at 2:46 AM Volker Schmidt <voschix at gmail.com 
> <mailto:voschix at gmail.com>> wrote:
>     I acknowledge there is a problem. I started out putting "gravel" on
>     many maintained unpaved roads, only to look up the wiki some years
>     later. I know use "fine_gravel" (taginfo 170k uses), which broadly
>     corrisponds to the "gravel" of "gravel bikes".
>     So, yes,  most of my "gravel" roads are really "fine_gravel", but I
>     have no idea how widespread it is, and also how much it depends of
>     the mapper's mother tongue.
>     I would not redefine the value "gravel", rather put a warning on the
>     page, pointing out that we have this wide spread confusion, and
>     invite mappers to consider "fine_gravel".
> I did the same thing -- tagged *many* roads with surface=gravel early on 
> and since then have been using surface=compacted for graded and shaped 
> roads made of fine gravel, surface=fine_gravel for roads where the fine 
> gravel was just dumped and and spread around without a lot of roadbed 
> preparation (many driveways and pedestrian walkways), and 
> surface=unpaved everywhere else.
> *Some larger-gravel examples:*
> Just last week I was exploring some agricultural tracks and encountered 
> some very large gravel that was quite challenging to ride on, not quite 
> 13cm track ballast, but much bigger than most of the gravel used on 
> roads, maybe 5-7cm. (images 
> <https://www.mapillary.com/app/?lat=44.099519799959175&lng=-73.2845288&z=17&pKey=qmTlSH8QhKgJ9NK0u1QuKT&focus=photo>) 
> I tagged this way <https://www.openstreetmap.org/way/19677175> as 
> surface=gravel based on the wiki definition, but would like to 
> characterize it differently from the other roads also tagged 
> surface=gravel that use much finer stone.
> I also recently surveyed this forest track 
> <https://www.openstreetmap.org/way/362871403> that has even larger 
> stones, a mixture from about 10cm-25cm. (images 
> <https://www.mapillary.com/app/?lat=43.24208888888889&lng=-73.01363055555555&z=17&pKey=L1GR6ZtaCiysWNyjEyBVwn&focus=photo>) 
> I tagged this track as surface=gravel.
> *Paths forward:*
> I think surface=gravel alone has far too much mixed-usage to 
> definitively say anything other than the surface is made up of random 
> stones that aren't individually laid.
> (A) More surface values: surface=fine_gravel could be augmented with 
> surface=medium_gravel and surface=large_gravel with guidelines 
> suggesting size ranges.
> (B) Additional tags: Keep using surface=gravel as the general category 
> and supplement with gravel=fine, gravel=medium, or gravel=large or 
> similar tagging scheme with size guidelines. Maybe add compacted=yes/no 
> where appropriate.

For surface=gravel where wheelchairs, bicycles and vehicles are a 
consideration, might it be worth updating the wiki to suggest tagging 
appropriate values of smoothness=* (with examples) to use in conjunction.

It won't solve the problem, but it might in the shorter help routers 
which understand smoothness=*

Robert Skedgell (rskedgell)

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