[OSRM-talk] Ferries dot gone?

J├╝rgen Barthel osrm at checkin.com
Sat Aug 13 20:13:30 UTC 2016


Hello Patrick and others, thanks for the response.

Being still new to this, it triggers a question that is related to OSRM 
as well.

On 12. Aug. 2016 18:58, osrm-talk-request at openstreetmap.org wrote:
> Combine that with the fact that most ferries don't have
> a `duration` tag (hence defaulting to a speed of 5 km/h), you will
> only see them used if there is absolutely no way.

A "dumb user" question: Anyone knows where the 5 km/h come from? And can 
I "see" easily, where ferry time is set and where those 5km/h are 
applied? Preferably from the OSRM feedback. We already check if a ferry 
is involved. But I could not find any "trigger" in the data examples I 
looked at. Or should I look for a "missing" value? Is there a "manual" 
beyond https://github.com/Project-OSRM/osrm-backend/blob/master/docs/ ?

We thought it might be wise to compare, but some tests we did with 
Google show major discrepancies.
I checked i.e. on the Ancona-Zadar ferry, showing 9 hour duration. 
Google shows 7 hours. Bing 5:46h. Our Logistics software Zero, as it has 
no ferry duration and is not as smart as OSM ;-)
http://www.jadrolinija.hr says it's a six hour trip. Plus you should be 
there 2-3 hours prior embarkation. So OSRM timing is correct, Google is 
min. one hour short, Bing is short net ferry time by 14 minutes...

Hmmm ... from a "dumb user" point of view it would likely be more 
accurate to have the ferry with six hours and the access road having a 
three hour "delay" in it? I saw a "lift gate", but did not see if that 
could be used to add that time.
So is the way it is the "correct" (pragmatic) way to set a ferry? Or is 
there a better one?

I added web, phone and a note explaining the 9 hours ferry time. Good? 
Can someone have a look? I especially don't want to compromise the OSRM 
results. :-]
And just to make sure: I assume that automatically works "both ways". Right?

> However in the case above, I think you are hitting a different
> problem: The island is not reachable because the paths on the ferry
> are not accessible by cars:
>
> http://map.project-osrm.org/?z=18&center=38.013485%2C12.512650&loc=38.013535%2C12.513288&loc=38.012737%2C12.511910&hl=en&alt=0
>
> http://map.project-osrm.org/?z=18&center=37.933299%2C12.325405&loc=37.933282%2C12.325196&loc=37.933227%2C12.325501&hl=en&alt=0
>
> I'm not sure if these ferries are generally accessible by car, but the
> tagging would need to be fixed for that.
Okay, I can add notes in OSM. But maybe someone here on the list has an 
idea where I could find a "HowTo" (RTFM) on how we can address those 
cases ourselves? It seems to be a common problem for OSRM and we can 
identify those cases as we calculate mass routes across Europe (and soon 
North America). We could "return" some of the benefit we take from using 
OSM/OSRM by improving the data?

Thanks your feedback, help and assistance!
Juergen



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