Mike N. nice...@att.net writes:
One thing I /haven't/ seen addressed yet is whether single relations are
preferred, or one relation for each way with a super-relation.
Currently both are in use, but I think it would be a lot easier for
future code if we pick one and move towards it from now on.
I don't see any advantage for a relation per way; a single relation
with roles for each direction has all the information needed by a
relation-user, and it's one less thing to keep track of when editing
or updating.
The potential problem I see is when you have a road that alternates
frequently between single- and dual-carriageways (which many state
routes do, and even a lot of US highways). How do you represent this in
a single relation?
1) Put single-carriageways in once, with no role. Or, with
role=north/south. Either way, this is difficult to recognize and
parse automatically. And aren't members of a relation ordered inside
the relation? (I know JOSM shows icons for whether a way is connected
to the ways before and after it in a relation.) The ordering loses any
meaning under this method.
2) Put single-carriageways in twice, once with role=north and once
with role=south. This is allowed, and fixes the problem, but don't
most editors complain when the same object appears more than once in a
relation?
In my view, having separate relations for each direction, and a
super-relation to hold them solves this problem. But maybe there's some
argument against them that I've missed.
Thoughts?
--
Peter Budny \
Georgia Tech \
CS PhD student \
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