[OSM-talk] [tagging] RFC :left/:right (asymmetrical roadside features)

Ed Loach ed at loach.me.uk
Tue Feb 17 12:45:00 GMT 2009

> Editor support is less
> important
> - and far easier to fix - than explaining to all the people who
> don't
> even realise that all roads have a direction in openstreetmap -
> and
> except for oneway roads, I have no idea which ways are pointing
> in
> which directions, and it shouldn't be important unless it *has*
> to be
> important.

I don't think people are going to arbitrarily use the :left/:right
tagging, except for cases where they feel it is necessary. It's
certainly not something people new to the project will do as a first
thing, and will only ever need it if they come up against something
they want to map which is more complicated. Hopefully then they'd
ask either here, on OSM-newbies or read the wiki to find a solution.

So left and right relative to the direction of the way in the
database (as displayed bottom left in Potlatch or with arrow heads
in JOSM), is a logical solution for where you have things on only
one side of the road (perhaps something like pavement:left=yes,
pavement:right = no or something). Similarly the :forward/:backward
proposal for where speed limits differ in opposite directions and
other such cases. 

Oneway is strange in that as well as yes/no you can have oneway=-1
for one way in the opposite direction of the way, and I still can't
work out why that is necessary.


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