[Tagging] decide on a meaning for what is not documented [way: Expressway=yes/no versus new tags "dual_carriageway=yes/no", "limited_access=", "grade_separated"=?]

[marc marc]

Hello,

Le 20.02.20 à 07:41, Joseph Eisenberg a écrit :
> I've created a page for Key:dual_carriageway based on existing usage
> in the database:
> https://wiki.openstreetmap.org/wiki/Key:dual_carriageway

how did you proceed? is the tag added by only one contributor to whom
you asked the question to create the page based on his answer?
or did several contributors suing this tag answer consistently ?

Because I noticed it with the depreciation of the undocumented tag
camp_site=camp_pitch : when a tag is undocumented, the real meaning of
the objects in the database depends on what was going through the heads
of the different contributors (for this particular tag, we have found 5
meanings each used more than 100x and it took hours and numerous
messages to ).

The great advantage of an undocumented tag is that we know that the
meaning is not documented. the contributors aiming at quality can
therefore avoid it. the users of the data too.
Conversely, a tag documented "by hidden guessing" degrades the quality :
Some people will believe that this is really the meaning of the objects
in the database when it's only a guess. at the very least, it would
require a big banner "a contributor guess that the meaning of the tag"

Regards,
Marc