[talk-au] *Round*abouts

Darrin Smith beldin at beldin.org
Thu Dec 11 22:00:16 GMT 2008


On Fri, 12 Dec 2008 06:53:44 +1100
Liz <edodd at billiau.net> wrote:

> 
> 
> Starting again about *round*abouts
> 
> The renderers accept two methods of drawing a *round*about.
> 
> There is a quick and easy method ideal for where two simple ways
> cross. Somebody has decided that this is called a mini-roundabout,
> and honestly I don't think that this item actually exists in
> Australian road design.
> 
> There is another method which needs someone to draw in four points 
> *square*about if we are lucky; *quad*about otherwise; and can extend
> to *dodeca*about if someone insists on creation of a beautiful form.
> With a way indicating one way drawn around the nodes, we can have a
> roundabout junction for the renderer.
> The renderers note a collection of straight lines and we don't get
> anything *round* at all.
> 
> JOSM makes awful circles if you request it to make a circle.
> Merkaator is a bit better but still makes deformed shapes.
> 
> So the maligned mini-roundabout is the only one where current
> renderers make a circle on the map.

This doesn't hold much water I'm afraid. Following this line of
reasoning all the curves on ways are invalid since they don't follow
the exact shape of the road. Besides as I said in another post this is
completely a rendering issue, they could be adjusted to turn the 4+
points into a circle/ellipse anyway. 

You are still equating mini_roundabouts and roundabouts as exactly the
same thing. Minis were defined as a very specific subset of roundabout
which all the pages YOU provided say are small roundabouts that can be
completely driven over. I notice you have failed to address this very
specific argument completely.

> Darrin, where does this *core* idea come from?
> I had not seen it until you mentioned it.

Ok, what's the very first line on the osm wiki about
junction=roundabout:

"A roundabout is a road junction where the traffic goes around an island
in the middle."

*Around* an *island* in the middle.

From the English wiki page about roundabouts also:

"Pedestrians are (usually) prohibited from the central island"
"All vehicles circulate around the central island in the same direction"

The island is a no-go no-mans land. 

-- 

=b




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