[OSM-dev] Proposal: Make relations ordered
richard at systemeD.net
Mon Mar 17 11:02:43 GMT 2008
> OK, fair enough. I hope JOSM and Potlatch get around to implementing it
> sooner rather than later then. It's rather annoying to carefully define
> a route relation, knowing that it can be blown apart by people who
> remerge the parts or split them in other ways. I tested this and it
> gives undesired results at the moment.
To be honest the thought of relations getting ordering fills me with
dread. Potlatch is only just about to get relations support (thanks
entirely to Dave Stubbs) in 0.8; the thought of having to redesign it
and add a load of crap to handle splitting/merging/whatever doesn't
exactly fill me with joy.
Plus there's a more general worry that with this, and with layers, and
whatnot, we're moving away from "simple is good" to "let's have a
super complex data model that covers all eventualities".
AIUI the problem you mention above is nothing at all to do with
ordering. It's because the editors don't make it sufficiently explicit
what is part of a route relation, and what isn't. If the editor
highlights such routes in a different colour (as Dave's excellent code
for Potlatch does) then users will _see_ when they split or merge
wrongly, and modify their behaviour accordingly.
Similarly I don't see why Frederik's initial ribbon-like loop
needs to be solved by ordering. One of the most frequently cited use
cases for relations is turn restrictions. Surely this is nothing more
than a non-mandatory turn restriction?
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