jim at jimavery.me.uk
Wed Aug 25 12:36:56 BST 2010
On 25 August 2010 09:07, Ian Spencer <ianmspencer at gmail.com> wrote:
> I came across a problem with Velomap, which I find is a good autorouting
> version of OSM for my purposes for cycling and still works fine for walking
> Velomap has made an assessment of the various tags to guess how best to
> route for bicycles on roads, tracks and paths. Being an international model
> there is a point where the definitions don't seem to work for the needs of
> the map. Most countries have a definition of trunk which can be paraphrased
> as "nearly motorway" whereas the UK has adopted a stance of "if it gets a
> green sign, it is a trunk road'. Velomap determines that highway=trunk means
> not suitable for cycling.
> I came across the A511 which goes through a little village and the detour is
> some 9 miles and there are clearly many roads like the A441 around Redditch
> where they are not true national routes, though they do link major(ish)
> centres which are acceptable cycling routes. It does of course mean that OSM
> matches commercial maps in displaying these routes and the decision to go
> with this tagging is well embedded in OSM.
> This can be resolved with a bicycle=yes tag.
> So my question is: should we be encouraging the tagging of bicycle
> accessible highway=trunk roads explicitly? My instinct is that all roads are
> accessible to bikes aside from M roads and those sections that are
> explicitly signposted as such. So the other workaround would be to produce a
> script to tag all UK trunk roads as bicycle=yes where not already tagged and
> then explicitly set the tag to bicycle=no where it is restricted.
> I recognise that Velomap is just one guy's interpretation, however, it is a
> reasonable interpretation from an international tagging perspective.
Personally I think that explicitly tagging roads which are already by
definition cycle-legal as bicycle=yes would be too onerous and not
entirely helpful. There are quite a few roads which are legal but
lethal for cyclists. I think the current advice under the heading
"Bicycle Restrictions" on http://wiki.openstreetmap.org/wiki/Bicycle
is the most pragmatic approach.
I don't know anything about how OSM maps get translated to GPS
routable maps - I would guess that the most important thing is to be
consistent in our tagging and let the lovely people who make the
routable GPS maps translate them as they feel appropriate.
Anecdotally I'm finding that the better I tag the official cycle
routes and lanes around where I live, the more likely it is that my
GPS will route me on a reasonably pleasant way (not using Velomap here
- thanks for the tip though, I'll take a look at that one too).
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