[Talk-us] Ferries

[stevea]

>Martijn van Exel <martijnv at telenav.com> writes:
>
>>  It turns out that this happens because some of the access roads to
>>  these ferries are tagged as highway=service, sometimes
>>  service=driveway. For various reasons we don't want to route folks
>>  through service roads, so this poses a challenge. Here's an example:
>>  http://www.openstreetmap.org/#map=19/48.42169/-123.37231
>
>Greg Troxel <gdt at ir.bbn.com> writes:  It seems wrong to adjust 
>tagging because of a particular router.
>
>I would say that you should fix your routing.  If they are service
>roads, but you don't want to use them, then you get the route your
>policy led to.
>
>I'm guessing you are trying to prevent routes that shortcut through
>service roads when such usage would be frowned on.  But at the same
>time, if you need to get someplace accessible only via a service road,
>that's what you have to do.
>
>Perhaps your router should just have a higher cost for service roads
>(somewhat fair, given lower speeds?), or a prohibition on
>regular->service->regular, such that regular->service->ferry is ok.

A very big +1 to this.  "Posing a challenge" to the construction of 
an accurate routing algorithm is a poor excuse to propose rippling 
through data changes for what would essentially be a one-off 
convenience.  Greg Troxel's suggestion about 
regular->service->regular and regular->service->ferry sounds 
perfectly reasonable and can certainly be made to work for this 
particular case.  Inside of a routing algorithm is exactly where this 
sort of decision-making belongs, not by making data changes that are 
more convenient for it.

SteveA
California