----- Original Message ----- From: Richard Weait <rich...@weait.com> To: Simon Wood <si...@mungewell.org> Cc: Talk-CA OpenStreetMap <talk-ca@openstreetmap.org> Sent: Mon, 22 Apr 2013 12:14:42 -0600 (MDT) Subject: Re: [Talk-ca] Routing tool for openstreetmap.ca?
On Mon, Apr 22, 2013 at 1:51 PM, <si...@mungewell.org> wrote: > > > > > http://map.project-osrm.org/ > > > > For Canadian data and the rest of the world. Updates the data twice a > > day, as I understand it. > > So is there a way to 'teach' that better routes? > > Blairmore to Calgary was routed through Fort McLeod (257km)... when the > faster/shorted route is via Highway 22 and 533 across to Nanton (217km). > > It might say something about my driving, but that would take a little over > 2hrs rather than suggested 3hr4. Yes, I average more that 70km/hr... > I'm not familiar with either route, or with your driving style. :-) Routers using OSM data will make assumptions where speed limit data in not available so you might be running into issues where the assumptions don't match your driving experience on the ground. In past, I've found that there are connectivity problems in the OSM data, when routers make suggestions taht I wouldn't expect. In fact, that was one of the things we were using the test instance of OSRM for; finding discontinuities, bad one-ways, and other tagging / mapping errors. Richard, Thanks for the link to the OSRM site, but I don't think that was it. I'm familiar with that project and recently have been following the dev list. At least as the demo site stands, it does give crazy routings for the area of South Australia where I am right now. And while it may be related to speed limit tags, it's not for the lack of them, but because they exist. The unpaved roads here have been "correctly" tagged with max_speed=100. While that is the statutory limit for unsigned rural roads in South Australia, it is not reasonable in practice. When OSRM sees that, it coughs up routes that suggest one exit reasonably good motorways and jump onto unpaved roads. Here's a good example: http://osrm.at/2Vl When routing from Adelaide to the Roseworthy Campus, OSRM routes one off the M20 and onto unpaved roads when staying on the M20 for one more exit, then exiting to Redbanks Road is the much more logical choice. The fact that OSRM updates data twice a day is encouraging. I didn't see that anywhere. But I've found that the Gosmore engine, at least as implemented by http://yournavigation.org makes more reasonable assumptions and so comes up with more logical routes. The problem there, however is that yournavigation appears to be using worldwide data over 2 months old. And hence my suggestion for an implementation of a routing feature that uses reasonable assumptions (or as best as we can agree to) and utilizing the latest Canadian data possible. It could be based on either the OSRM engine or the Gosmore engine I would imagine. It seems to me that the OSRM routing could benefit greatly by a 0.6 penalty for unpaved roads as had been suggested a few time before, but they don't seem to want to go that way. Thanks, Sam _______________________________________________ Talk-ca mailing list Talk-ca@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-ca
