[Tagging] surface=gravel problems

Mateusz Konieczny matkoniecz at tutanota.com
Thu Apr 15 07:56:56 UTC 2021

For long time this tag was described at Key:surface page as 
"Broken/crushed rock with sharp edges, known as ballast on railways. Usually loosely arranged.
Typical size for road and surface construction range between 4 and 8 cm".

( https://wiki.openstreetmap.org/wiki/Key:surface )

But it turns out that surface=gravel is primarily used for roads where far smaller 
pieces of rocks are used.


It is result of 
- "gravel roads" term is often used in many countries for something where far smaller pieces
  of rock are used, some of such roads would qualify for surface=compacted.
  See https://wiki.openstreetmap.org/wiki/File:Gravelsign2.jpg
- "gravel" and equivalent terms in other languages is often used by people to refer to pieces
  of rock far smaller than 4cm
- there was not good tag for roads with surface of small loose gravel 
  (surface=fine_gravel at https://wiki.openstreetmap.org/wiki/Key:surface has
  "A multilayer pavement with a stone or gravel basis and a topmost surface of firm, granular grit,
  basalt or quartz," what anyway excluded cases of some gravel thrown on earth/mud/drt )
- surfaces matching old Wiki definitions are existing but really rare 


How one may know that Wiki definition mismatches actual use?

Surfacing roads/paths/etc with track ballast-sized pieces of gravel is extremely rare
(though it happens)

but in actual use surface=gravel is extremely common, far more common that
old Wiki definition.

So actual use clearly mismatches wiki definition.
In addition, many people using surface=gravel were unaware of this definition and unaware
that such surfaces described in Wiki actually exist!

See https://lists.openstreetmap.org/pipermail/talk-au/2021-March/014445.html



It turns out that surface=gravel is for anything from "basically compacted" to
"basically track ballast".

I recommend checking https://wiki.openstreetmap.org/wiki/Key:surface in your language
and updating definition to match actual tag use.

It would be nice to find some good tagging for surfaces like

surface=track_ballast? surface=huge_gravel? surface=ballast?

It would be also nice to find some more specific values for 
cases of small gravel thrown on mud/dirt/grass - as surface=gravel
turns out to be very unspecific ability to tag this in detail would be great
(useful especially for cyclists)

surface=small_gravel? Something else?


PS AAAARAGAGAHHA. Tag used over 1.5 million times had actual use and OSM Wiki
definition completely and utterly mismatched.

And we need new tags and resurvey of 1 500 000 elements to have useful information about surface.

Right now surface=gravel may be both 
that for many purposes are worth distinguishing.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/tagging/attachments/20210415/1cc3e643/attachment.htm>

More information about the Tagging mailing list