On 2012-11-22 09:41, Wolfgang Wienke wrote:
Am 22.11.2012 07:50, schrieb Maarten Deen:
On 2012-11-21 20:48, Wolfgang Wienke wrote:
Am 21.11.2012 18:48, schrieb Maarten Deen:
On 11/21/2012 06:45 PM, Maarten Deen wrote:
On 11/21/2012 06:41 PM, Wolfgang Wienke wrote:
> Hi,
> I'm mapping in NL near Aachen. Can someone tell me, why there
is more
> that ONE way in a dutch roundabaout?
There isn't. A roundabout is always one way. If there are two
directions
it is not a roundabout but a circular road.
Just after sending this I realized that I must have misread your
question. You mean why most roundabouts are made up of more than
one
way.
Initially it is because of the AND import. The AND dataset was
such that
between every junction of 3 or more roads there was a sperate way.
What means the AND dataset?
AND donated their dataset in 2007 and was subsequently integraded
into OSM.
<http://wiki.openstreetmap.org/wiki/AND_Data>
I do not find there any special about roundabouts. I think, that it
is important to recognize a roundabout for navys to tell the user
something like "leave the rounabout at the second street".
Is there no discussion in Netherlands to join the automatically
generated part of a roundabout manually?
No, because that is not necessary.
The AND data was structured such that at every point where there is a
juntion of three or more ways, a new way was created. You'll still see
that in lots of parts of the Netherlands:
<http://www.openstreetmap.org/?lat=51.319581&lon=5.996067&zoom=18&layers=M>
It is not necessary that the road "Lindanusstraat" is split up in 5
parts, but that is how the AND dataset came. You'll notice the
AND_nosr_r tags on these ways, so you can see it came from AND that way.
The same with roundabouts. Because every connecting road is a point
where 3 ways connect, it was a different way.
Routing engines have no adverse effects from this. There is no
(sell-respecting) routing engine that will tell you to "continue for 100
metres" a thousand times when the road is spilt up in smaller ways. So
why would it do that on a roundabout?
A roundabout is recognized by its tag: junction=roundabout. Not by its
physical properties (a circular one-way street).
Now it is just convenient if you have different relations (like a
bus
line) over the roundabout. Then you can indicate exactly which
side a
relation takes.
Well, this is really not necessary because you drive the roundabout
alwas in the same direction.
In Germany we only have roundabouts made of ONE way. If you use the
relation-editor of JOSM, than you can easily recgnize a roundabout.
Would it not be easier, to use only ONE way in a roundabaout?
I think this looks much tidier than when roundabouts are always one
way.
<http://www.openstreetmap.org/?lat=51.32506&lon=5.97571&zoom=17&layers=T>
Also, if you make a route over a roundabout, you never use the full
roundabout, so why would you want the full roundabout in the
relation?
Of course this is true, but I think it looks tidier the other way,
look here. You see at once, that there is a roundabout.
http://www.openstreetmap.org/?lat=50.791022&lon=6.059449&zoom=18&layers=T
I don't see the difference there because it has only single ways
connecting to the roundabout.
But let me ask this simple question: if you go from A to B via a
roundabout, do you traverse the whole roundabout or only a part of it?
Why then add the full roundabout to a relation that describes the route
from A to B?
It is also clearer not to add the full roundabout. Take this example:
<http://www.openstreetmap.org/?lat=51.333905&lon=5.995042&zoom=18&layers=T>
It is immediately clear that bus 62 goes from east to west. If you had
the complete roundabout in the relation, the whole roundabout would be
red and you would not know which direction the relation had.
Regards,
Maarten
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