[Tagging] exit_to on motorway_junction

Johan C osmned at gmail.com
Wed Nov 21 22:50:42 GMT 2012

Overlooking the discussion so far, I think exit_to cannot be deprecated.
However, there's strong feelings to support both destination and exit_to.
In my opinion, the following things can be done:

1. keep things the way they are now (where exit_to is the preffered choice,
because the text on the motorway_junction page states that it should be
used). The disadvantages of exit_to are not solved:
a. no description of exit_to
b. no solution of the exit_to_left yet to support both branches
c. not clear why other items of a exit ramp are not used in the
motorway_junction tag (like lanes, maxspeed)
d. no support for advanced lanes tagging
to summarize: no support for a lane assistant

2. deprecate destination
disadvantage the same as above, so no support for a lane assistant

3. deprecate exit_to
several U.S. OSM'ers do want to keep on using exit_to

Possible solution in this discussion. The non-U.S. OSM'ers in this
discussion seem to favour destination. The U.S. OSM'ers seem to favour
exit_to. Lets split it in the text of motorway_junction tag. I do have a
text suggestion for that. Please send your thoughts on this. You can see I
also try to adress the realtion discussion, which I think can be handy, but
I don't see the value for motorway exit tagging. Destination can do the
trick there, and a relation is more complex = less KISS

The tags destination <http://wiki.openstreetmap.org/wiki/Key:destination>=*
 , destination:ref <http://wiki.openstreetmap.org/wiki/Key:destination:ref>
=* (according to information on road signs) and *lanes*=* should be used on
the ways directly after the exit. The tag
=* can be used on complex motorway_junctions. These tags are needed to
support a lane assistant in navigation devices.

In the United States exit_to<http://wiki.openstreetmap.org/wiki/Key:exit_to>
=* on the motorway_junction node should be used to detail the destinations
where the junction exits to. The tag
be used in non-motorway situations.

This part of the exit_to will in my text suggestion be moved to the exit_to
Wiki page:

—for example, if signage states a road leads to Anytown on the A1000…
exit_to <http://wiki.openstreetmap.org/wiki/Key:exit_to>=Anytown
if multiple destinations are shown on signage, tag them with semicolons:
for example, exit_to <http://wiki.openstreetmap.org/wiki/Key:exit_to>=Anytown
A1000; Elsewhere A1001;
note that Anyvillage doesn't have a ref number.

2012/11/21 Colin Smale <colin.smale at xs4all.nl>

> Using only exit_to there is no way to handle junction topologies other
> than a straightforward highway exit, where there is one "big" through road
> and one "small" road leaving. What about wrong-side exits? Or where the
> highway splits into two (or more) roads of equal importance?
> Destination tagging is used a lot in the Netherlands, placed on the first
> segment of each way *after* the node where they split. My Garmin warns me
> ahead of time which side to keep to, so there doesn't seem to be a need to
> start the tagging at the first sign (which may be 1km or more before the
> actual junction). I have not yet found a case where adding destination=*
> around a junction felt like the wrong thing to do.
> IMHO destination=* on the ways is the right balance between the
> rudimentary exit_to on the node and using a relation which will have
> problems with support/adoption by both mappers and toolmakers.
> Colin
> > I don't see any reason to deprecate exit_to, it seems to be the simplest
> > method of mapping a destination sign on a motorway junction or similar
> > exit. I use exit_to fairly frequently and it has been a documented tag
> > for a while (although on the motorway junction page rather than it's own
> > page) and is also used in JOSM presets.
> >
> > I feel it is a less ambiguous tag than destination (as a tag on a way)
> > as it shows the specific point where a destination is signed, unlike
> > destination tagged on a way. If you use destination as a tag on a way
> > then I think you'd need to be sure that at every point along that way
> > the destination(s) given is the same throughout and if not or you didn't
> > know you'd need to split the way. The Taginfo stats also seem to show
> > that exit_to is the most popular of the three different ways of mapping
> > destinations: a destination relation, exit_to on a junction node, or
> > destination as a tag on a way.
> >
> > A destination relation is also a clear way of mapping a destination as
> > the intersection and both the 'from' and 'to' ways are part of the
> > relation, and is particularly useful in mapping situations where exit_to
> > wouldn't work (like at a crossroads) so I do also use this method. It is
> > however more complex (and so is unlikely to be a method that a new
> > mapper would be able to use) particularly where there are multiple
> > destinations given on a sign which requires a relation for each
> > destination.
> >
> > Cheers,
> > Paul Williams
> > (Paul The Archivist)
> >
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> >
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