[Tagging] default value for "oneway"

[John Packer]

>
> For a street, there is no practical difference nowadays between "no"
> and "unset", which is a smell for me. Either way means no.
>
For the software? No, there isn't a difference.
For the mapper?  Yes, there is a difference.

Since nowadays NULL for a street means oneway=no a change in the
> semantics would be still be possible as far as the database is
> concerned. If you go today to the database and update all oneway
> attributes for streets which are blank to "no", the meaning of the
>
database is equivalent.
>
Theorically speaking, yes, you could add oneway=no to every street, and get
a functionally equivalent database (from the software's POV).
But, in practice, people most likely wouldn't agree with that (this change
would be reverted).



2014-08-28 12:33 GMT-03:00 Xavier Noria <fxn at hashref.com>:

> On Thu, Aug 28, 2014 at 5:21 PM, Simon Poole <simon at poole.ch> wrote:
>
> > In any case there are roughly 45 million highway segments on which a
> > oneway tag could make sense, vs. roughly 6 million oneway=yes and 1.5
> > million oneway=no. I suspect that it is really -far- too late to change
> > the semantics of this specific attribute.
>
> Since nowadays NULL for a street means oneway=no a change in the
> semantics would be still be possible as far as the database is
> concerned. If you go today to the database and update all oneway
> attributes for streets which are blank to "no", the meaning of the
> database is equivalent.
>
> Same for motorways, replace all NULLs with "yes". Equivalent database.
>
> For a street, there is no practical difference nowadays between "no"
> and "unset", which is a smell for me. Either way means no.
>
> I believe the default is useful for the UI, to preselect a value for
> example so that the user has to do nothing in the majority of street
> creations, less useful as a way to interpret NULLs because then you
> don't know what has been confirmed.
>
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