[Tagging] Another reset on roundabouts

Andrew Errington erringtona at gmail.com
Fri May 18 02:59:31 BST 2012

On Fri, May 18, 2012 at 7:21 AM, Toby Murray <toby.murray at gmail.com> wrote:
> Otherwise we can pontificate all we want on the mailing list but
> people who are not familiar with the concept of a "real"
> mini-roundabout WILL still use this tag for "small roundabouts" with
> non-traversable centers. That's just reality. Maybe change the display
> label to "traversable roundabout" or something?

If the definition is clear in the wiki then there should be no
problem.  Anyone discovering something in the database that does not
match the definition is free to correct it.

In real life the definition is quite clear.

We have two distinct nouns, 'roundabout' and 'mini-roundabout'.
Although 'mini-roundabout' is made from two words which have a
well-understood meaning, the compound word has its own specific
meaning.  Adding a further definition (such as 'traversable
roundabout') is not necessary, since, by definition, a mini-roundabout
is traversable, and a roundabout is not.  Furthermore, it is very
clear to me what these two tags would mean on a node.
'Mini-roundabout' on a node means this this a mini-roundabout.  It is
small, and it is traversable.  'Roundabout' on a node means this is a
small roundabout, but it was too much effort (or too tedious) to draw
a circular way.  It is not traversable, and traffic must 'go around'
it based on the local rules for direction and giving way.  Anyone who
discovers 'roundabout' on a node is free to re-draw it as a small
circular way.  The net effect to routing should be negligible.

I think the problem is that we use 'mini-roundabout' with highway=*
and 'roundabout' with junction=*.  In my opinion they should both be
junction=*, with 'mini-roundabout' restricted to nodes, and
'roundabout' applicable to nodes or circular ways.  Furthermore, when
applied to a node we should probably encourage the tag direction=*
although some software can probably figure that out.

Best wishes,


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