[OSM-talk] Should Bridges be independent of their ways?

[Lester Caine]

Martin Koppenhoefer wrote:
> 2009/9/19 John Smith <deltafoxtrot256 at gmail.com>:
>> 2009/9/19 Martin Koppenhoefer <dieterdreist at gmail.com>:
>>> don't get you. Isn't "mapping lanes" just the same like what I
>>> suggested? I'm in favour of mapping all lanes and ways as well, but
>>> you DO need relations to combine them into streets (indicating kind of
>>> separation and / or possibility to change lanes). I was in this case
>>> just talking about the bridge, but for streets I can imagine the same
>>> procedure (and add green, dividers, walls, curbs, etc. as well)
>> Why do we need relations to combine "lanes" into "ways".
>>
>> Wouldn't it make more sense to tag lanes of ways?
>>
> 
> what do you mean? We are already doing this: lanes=3
> In simple cases you don't need it, and when it get's complex, IMHO
> explicit mapping is the only transparent and easy way to solve the
> issue.
> One of my favourite example is this situation:
> http://maps.google.it/maps?hl=de&ie=UTF8&ll=41.866627,12.49679&spn=0.000684,0.001206&t=h&z=20
> 
> you will get just confusion when you start to count lanes and tag
> things like lane:11=oneway, no_right_turn
> Usually at crossings you will have different turnrestrictions for
> parallel lanes. Lanes are starting and ending (even small ones as for
> busses, to turn, etc.).

The same problem has come up in other recent threads.
lanes=6 answers the mapping problem, but does not provide enough 
information when 100mts before it was lanes=5 ....
Which side has the extra lane appeared? ARE there 3 lanes each way? or 2 
lanes one side with 3 opening to 4 on the other side as one becomes a 
slip road off the side, and the lanes=5 actually has a single lane side 
route.

When creating routing information how do you pick up things like this 
and handle the move into xxx slip road (left or right depending on which 
side of the road you drive ;) )

We do not need to replace long tracks of simple lanes=2 where there is 
no doubt, and road junctions where several differing routes through are 
allowed will remain a problem, but detailing the lanes of a way where a 
complex junction is involved seems an essential area to come to some 
agreement? With micromapping the lanes being the only obvious way to 
handle it.

-- 
Lester Caine - G8HFL
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