[OSM-talk] routing across open spaces

[Anthony]

On Tue, Nov 30, 2010 at 6:57 PM, David Murn <davey at incanberra.com.au> wrote:
> On Wed, 2010-12-01 at 12:01 +1300, Robin Paulson wrote:
>
>> > That's nonsense.  A way does not show a right of passage.  A
>> > particularly tagged way shows a right of passage.  And a park is a
>> > particularly tagged way.
>
> No, a park *CAN BE* a particularly tagged way.

Can be?  How can you represent a park in OSM without using a way which
is tagged with leisure=park?

> Just like a road, if it
> isnt tagged properly with oneway/access/barrier/etc, the routing will be
> inaccurate.

Correct.  What are you getting at?

> Actually, the fact that its not tagged correctly is a big part of the
> issue.  The renderer has to make assumptions if its not tagged.  If
> there was a tagging scheme to indicate that an area was traversable,
> then routing engines could start to use it,

There is such a tagging scheme.  It is described at
http://wiki.openstreetmap.org/wiki/Access

> but Id hate for a routing
> engine to try and take a short cut 'as the crow flies' through an area
> which hasnt got ways marked to follow.

I'd love it.  It's a feature I'm quite looking forward to.  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.

> To take that to a further level,
> what if someone marked a national park as an area, should routers simply
> show a route ATCF or should it only route through a national park area
> if there is a way to follow?

Routers shouldn't route through all areas the same, any more than they
should route along all non-areas the same.  An area tagged with
leisure=park wouldn't have the same access defaults as an area tagged
with building=yes.

And an area representing a national park should not be tagged with
leisure=park.  This is explicitly stated at
http://wiki.openstreetmap.org/wiki/Park

"Parks in rural locations (e.g. areas named "National parks") are a
totally different kind of thing. leisure=nature_reserve and
boundary=national_park should be used, and not this leisure=park tag."