[OSRM-talk] U-turns in Map-Matching Algorithm

Matthias Schwamborn schwamborn at informatik.uos.de
Thu Jul 23 13:47:03 UTC 2015


Hi Patrick,

thanks for the clarification. So this check is for the input
coordinates, only, right? What if some candidates introduce a U-turn
(e.g., due to some outliers in the input data)? Thanks.

Best, Matthias

On 22/07/15 12:17, Patrick Niklaus wrote:
> Hey Matthias,
> 
> What the algorithm at that point does is check if the original trace
> might contain a U-Turn at that point. If so it does not add separate
> candidates for each direction (but bidirectional edge based nodes),
> resulting in the possibility of U-Turns at that position.
> 
> Hope this helps.
> 
> Best,
> Patrick
> 
> On Wed, Jul 22, 2015 at 11:28 AM, Matthias Schwamborn
> <schwamborn at informatik.uos.de> wrote:
>> Hi all,
>>
>> looking at the code in plugins/match.hpp [1], I noticed that candidates
>> resulting in a U-turn are allowed but wouldn't you say that these
>> candidates are actually pretty unlikely compared to candidates that
>> don't result in a U-turn? Am I missing something here? Thanks.
>>
>>
>> Best, Matthias
>>
>> [1]
>> https://github.com/Project-OSRM/osrm-backend/blob/master/plugins/match.hpp#L104
>> --
>> Matthias Schwamborn
>>
>> University of Osnabrück         Tel.:   +49-541-969-7167
>> Institute of Computer Science   Fax:    +49-541-969-2799
>> Albrechtstr. 28                 E-mail: schwamborn at informatik.uos.de
>> D-49076 Osnabrück, Germany      http://cs.uos.de/schwamborn/
>>
>>
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> 
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-- 
Matthias Schwamborn

University of Osnabrück         Tel.:   +49-541-969-7167
Institute of Computer Science   Fax:    +49-541-969-2799
Albrechtstr. 28                 E-mail: schwamborn at informatik.uos.de
D-49076 Osnabrück, Germany      http://cs.uos.de/schwamborn/

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