[Openstreetmap] key values to represent restricted turns

[Andy Robinson]

There are going to be a ton of examples where the actual street layout is
complicated resulting is complications for navigational use. So I was
looking at my navigation software in closer detail at the weekend and found
it less than ideal at dealing with complicated junctions and as a result
sometimes gives out erroneous navigation messages.

For example, there are many locations here in the UK where a bus lane gets
priority on the approach into a roundabout, this is mapped as a separate
lane (on the left here in the UK) as it is properly divided. However the
software does not realise it has a restriction and gives the instruction to
"keep left" as this represents the shortest (or perhaps even quickest) route
when in fact you should keep right.

>From what I can see, all of the navigational mapping products use maps which
are based upon real conditions on the ground. It's just that perhaps not all
of the restrictions etc are properly picked up when the mapping is made or
they are not sufficiently up to date. It's quite daunting to think that
Teleatlas have as many as 160 attributes they can tag an entry with.

Andy

Andy Robinson
Andy_J_Robinson at blueyonder.co.uk 

>-----Original Message-----
>From: openstreetmap-bounces at vr.ucl.ac.uk [mailto:openstreetmap-
>bounces at vr.ucl.ac.uk] On Behalf Of Frank Mohr
>Sent: 24 January 2006 01:42
>To: openstreetmap at vr.ucl.ac.uk
>Subject: Re: [Openstreetmap] key values to represent restricted turns
>
>Tom Carden wrote:
>> On 1/23/06, Simon Hewison <simon at zymurgy.org> wrote:
>>
>>>If anyone can think of any better way of representing such constructs,
>>>please discuss it here.
>>>
>>
>>
>> How about something like a property on a node like
>> no-turn=a.b,c.e,e.d; where a/b/c/d/e are segment ids for segments
>> connected to that node, and order matters?  All other combinations are
>> fair game for routing.
>
>this would also solve the problem in situations like this
>
>                <-
>   <->      /------------------
>-----------*
>            \------------------
>                ->
>
>but in my opinion, the oneway tag should belog to the line
>
>Another problem I found are traffic lights
>Each day I see two junctions like this
>I'd collapse that junction to a single point
>as it just looks bigger in ascii art as on the map
>
>
>--------------------+---+---------------<- (1)
>------------+-------+---+------+-------->-
>             \      |   |     /
>               A    B   C    D
>                \   |   |   /
>                  \ |   | /
>                    +   +
>                     \ /
>                      |
>                     (2)
>                      |
>
>(remember we are driving on the wrong side here in Germany ;-)
>
>(1) -> (2) from the left  side goes over A without traffic light
>(1) -> (2) from the right side goes over B with traffic light
>
>(2) -> (1) to the left side goes over C with traffic light
>(2) -> (1) to the right side goes over D without traffic light
>
>
>
>
>
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