[Talk-us] Time to retire ref= on ways?

Paul Johnson baloo at ursamundi.org
Mon Mar 8 10:36:30 GMT 2010


It's time to retire ref=* on highway=* ways to describe attributes
of the overlying route instead of the physical attributes of the way
itself.  Using the ref= tag on ways to describe routes simply
creates more problems than it solves for many reasons.

* The ref=* tag on a way is describing properties of a route that
is using the way, not a property of the way itself.

* Many bridges and tunnels have signed references that would
actually be physical attributes of a way, but with the ref= tag on
ways describing the overlying route instead of the way itself,
makes it impossible to properly describe these attributes if ref= on
a way is describing the route above the way, not the way itself.

* The ref= tag as defined for ways now includes more than the ref,
but also the network.  ncn_ref, int_ref, etc were created as an
attempt to describe network references uniquely, but there aren't
*_ref keys for every possible network already in play.

* The US has two federal highway networks, each state has it's own
highway network, and counties and cities have the option for their
own local networks.  That's at minimum 52+ *_ref keys that would be
needed to describe each network uniquely...for the US alone!  And
we're not even into transit or other routes that might use the way!

* Munging the modifier=, network= and ref= tags provided by
relations into a single do-all ref= tag creates more problems than
it solves, particularly for formatting.  It also creates
hard-to-answer questions for renderers and parsers.

* Multiple routes, particularly when they are involved in multiple
networks, creates unmanageable way ref= tags. It also makes it
more difficult to describe attributes that belong to the route,
not the way itself (such as which direction it's going, whether it's
a bypass, business, toll or other sort of route, etc).

Given that we have route relations, and have had them for some time
now, perhaps now is the time to:

* put ref= information pertaining to the route that travels on the
way to a relation for that route.  Provide facilities to search by
network and ref on relations.

* Actively remove ref= tags describing routes from ways that have
route relations already:  Let's kill this dinosaur.

Thoughts?






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