[Tagging] Status of oneway=cw oneway=ccw

osm at hjart.dk osm at hjart.dk
Fri May 3 14:07:18 UTC 2019


>>> For a non-roundtrip route consiting of two consecutive ways the route
>>> direction can be deduced from the order of the ways in the relation.
>> 
>> That's assuming the ways are ordered at all. I've cleaned up hundreds 
>> of routes (most created by Potlatch users though) and my advice is: do 
>> not rely on routes being ordered.
> 
> In OSM a relation is by definition an ordered list, see
> https://wiki.openstreetmap.org/wiki/Relation :
> "A relation is a group of elements. To be more exact it is one of the
> core data elements that consists of one or more tags and also an
> ordered list of one or more nodes, ways and/or relations as members
> ..."
> 
> Also the elevation profiles for the routes (e.g. in
> waymarkedtrails.org) only work if the routes are ordered and they
> usually look ok, see also
> https://wiki.openstreetmap.org/wiki/Relation:route#Order_matters .
> 
> If some editors damage the order in the relations this is a bug that
> should be fixed anyway.

In order to sort the members of a relation in JOSM, you need to download 
all of them. The majority of edits to relations involve downloading only 
2-3 members. If only 1 member is added or removed, that's how they 
become unordered.
Personally I'd prefer it stays like that, because I've seen complete 
newbies make some really weird edits to cycleroutes, because they 
obviously didn't understand what it was.
> 
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