Dermot McNally wrote:
2009/2/28 Mark Burton <markb@ordern.com>:
Yes, I think that is the key to getting good routes. Somehow, you need to make the GPS want to use the motorways rather than the trunk roads.
As long as we're on the topic of speed profiles of road types - I've seen a case where my Nuvi needs to route from one motorway to another. It's basically the route as shown here:
http://data.giub.uni-bonn.de/openrouteservice/index.php?start=-6.2430356,53....
You can see here that OpenRouteService chooses a sub-optimal route, in favouring a short spell on the roundabout over a longer stretch (leading to an overall shorter route) on a motorway_link.
In any case, the Nuvi makes the same mistake. Do roundabouts need to be de-prioritised somehow?
Dermot
I have to say that I've not seen this before. Whenever I encounter a similar situation there's no problem. See below for an example. http://data.giub.uni-bonn.de/openrouteservice/index.php?start=-6.2430356,53.... Your example clearly behaves differently but I can see no reason for it. If I had to guess I'd say that it's due to the very shallow angle between the start of the link road and the main carriageway as I can't see any reason for it in the data Additionally the following shows that for the same roundabout approaching from the South then the behaviour is as expected http://data.giub.uni-bonn.de/openrouteservice/index.php?start=-6.2430356,53.... Cheers Paul