[OSM-talk] routing across open spaces

[Anthony]

>> >> One day OSM will be able to route me from Linkwood Avenue to Pine Bay Drive
>> >> through the park
>> >> (http://www.openstreetmap.org/?lat=28.07187&lon=-82.550402&zoom=18&layers=M),
>> >> saving me 50 minutes of walking.
>> >
>> > Imagine if you tried to save 50min by getting routed across Albert
>> > Park[1].  That big thing in the middle of the screen is a lake that
>> > extends almost the entire length of the park, hence you'll notice all
>> > the walking paths have been mapped in, to allow you to be routed through
>> > the park appropriately.
>>
>> You forgot the link, so I'm going to imagine that the lake was mapped.
>>  Obviously a lake is by default foot=no.
>
> My mistake, sorry.  The link I tried to post before, is
> http://www.openstreetmap.org/?lat=-37.84597&lon=144.97075&zoom=16
>
> If you look at aerial imagery, you'll see most of the park is open
> grassland and the lake, however there is a path network in the park,
> which is appropriately mapped and tagged.

Right.  Clearly the lake is not routeable, and any routing engine
would have to route around the lake :).  The fact that the
non-routability of the lake takes precedence over the routability of
the park would be for the same reason that a lake is rendered on top
of a park.

Anyway, I looked around at a few places labelled leisure=park, and the
usage is all over the place.  I'd say based on that very unscientific
sample that it's probably best for routers to use a default of
access=unknown for leisure=park areas, and only use parks for short
cuts if they're explicitly tagged with something like foot=permissive.

Alternatively, I guess it wouldn't be horrible to add something like a
highway=shortcut tag, so mappers could be explicit about it.  If we've
gotta add foot=permissive by hand anyway, it's not that much more work
to add a few extra ways.