[Tagging] Best practices regarding implied tags
Matthew Woehlke
mwoehlke.floss at gmail.com
Thu Sep 17 12:55:25 UTC 2020
On 16/09/2020 18.32, Paul Johnson wrote:
> No, it's not wrong to add implied tags explicitly. It's actually
> encouraged in some cases where the implicit tag is not consumable by
> automated system (such as the "none" default for turn:lanes tends to be
> ambiguous between "you can't turn from this lane" and "you can't use this
> lane" and "there's an implicit but unspecified implication that isn't
> painted on the ground")
Pedantic: wouldn't "you can't turn from this lane" be correctly
specified as turn:lanes=through? As I understand turn:lanes, "none"
would be "you can't use this lane". (Also pedantically speaking, a blank
value would mean there are no specific markings. I think the only
ambiguity here is that it's unclear if the tag is simply missing — in
which case the truth on the ground could be *anything* — or if there are
no markings. Sort of like how a missing oneway could mean oneway=no, or
could mean oneway but not tagged.)
(Incidentally, I tend to add oneway=no whenever possible... or at least
I did in iD, which made it easy. I can't recall now how well I've been
keeping that up with JOSM.)
--
Matthew
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