It may appropriate to consider several metrics, but I also think it important to get a first version running. Another way of saying this is iterate and add refinements over time.
Metrics to consider (pre vs post redaction) in roughly order of complexity: 1. Distance of route (using segment lengths, not end point to end point) 2. Number of ways/way segments traversed (rough but perhaps useful) 3. Actual route. For example, in the case of NY to LA, it is reasonable to expect that once the route enters a motorway at one end, it will stay on motorways or motorway_links until near the endpoint. It might be appropriate to run both directions and use the first entry into a motorway at either end as the "near the endpoint" locations. This might be computed using pre-redaction data. 4. Over time, as fixes are applied, tighten difference checks to finer precision results. On Fri, Jul 20, 2012 at 12:24 PM, Toby Murray <toby.mur...@gmail.com> wrote: > I think this topic deserves its own thread. > > On Fri, Jul 20, 2012 at 11:20 AM, Kai Krueger <kakrue...@gmail.com> wrote: > > > > OK, I have had a first stab at it. > > > > http://apmon.dev.openstreetmap.org/us_routing_grid.html > > > > It is only 25 cities so far, but if it turns out to be useful it can > easily > > be extended to more cities. > > > > The big problem though is automatically figuring out if routes are > broken or > > not and then colour them red or green accordingly. At the moment it > doesn't > > do this at all. > > > > Anyone have some good ideas for this? > > > > The routing information is obtained from "Open Source Routing Machine", > > which is amazingly fast at calculating all of these long distance routes. > > OSRM updates its data daily, so I think the routing data is based on OSM > > data from yesterday. I.e. post redaction. If there is interest I could > > regenerate this routing grid daily too. > > > According to the wiki page, the old system used the as-the-crow-flies > distance between two cities as a basis. If it was more than 50% > longer, something is wrong. Not sure if that would still give > appropriate results or not though... There may be enough connectedness > now on secondary roads that the distance isn't off by quite that much > any more even with routing problems. I just did a route on OSRM from > NY to LA and it came out to just under 3,000 miles which seems about > right but there are some obvious routing errors. For example it gets > off of I-70 and goes through town in Saint Clairsville, Ohio but it is > about the same distance so things like this won't show up in the grid. > Hmmmm > > Toby > > _______________________________________________ > Talk-us mailing list > Talk-us@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-us > -- John Novak 585-OLD-TOPOS (585-653-8676)
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