[OSM-talk] [Tagging] - RFC -Motorway_linkimpliesoneway=??

[Matthias Julius]

Philip Homburg <pch-osm-talk at u-1.phicoh.com> writes:

> In your letter dated Wed, 8 Oct 2008 10:07:40 +0200 you wrote:
>>On Wed, Oct 8, 2008 at 9:29 AM, Philip Homburg
>><pch-osm-talk at u-1.phicoh.com> wrote:
>>> [...]
>>> I don't think that a relation should be used to imply oneway=yes. It's just
>>> too risky.
>>> In a country where just all trunk roads are dual-carriage ways, defaulting
>>> to oneway=no is just too risky.
>>
>>having different defaults for different countries is going to be a
>>problem anyway, since not every developer is going to know every
>>country default
>
> Most developers don't speak Italian either :-)
>
> But seriously, what I expect is a set of rules of the form "if in-germany
> then highway=trunk implies oneway=yes".

This leads to a nightmare.  Those rules would need to be implemented
in every tool that works with OSM data (and cares about oneway
properties).

I am for the simple aproach: If it is oneway - tag it as oneway.

If we really must have implied values for certain properties, keep
that simple as well and don't make in dependant on too many tags
(like: it's oneway if it is in Germany, but not in Saxony or on an
island and only if the speed limit is above 80 km/h, or, if it is in
France and ...) [I know I am exaggerating.]

And implied values should be clearly indicated on Map Features not
only on the individual tag pages.

Matthias