[OSM-talk-nl] junction= roundabaout

Robert Elsenaar robert at elsenaar.info
Thu Nov 22 11:23:17 UTC 2012


At the other way,  as we do it in Holland every roundabout should be tags in a forward and backward way in relations when the roundabout is split up. One of the reasons relation get polluted. 

But your drawing argument is a illegal one.  We do not map for the renderers. And all relations are two sided so always the whole roundabout is used. 

When you draw a route from a to be the routing software has to be smart enough to colour only the part of the roundabout from way a to be into the right direction. 

Met vriendelijke groeten 
Robert Elsenaar

Maarten Deen <mdeen at xs4all.nl> schreef:

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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