Hi, I do not yet believe that the service roads are causing this. I saw +1000<tel:+1000>km detours when reverting a much shorter route. I cannot test it during the next weeks Ciao Gerd ---- Samuel Longiaru schrieb ---- Hi Andrzej, I like the simplicity of the tag idea, but implementation I'm sure would be rather spotty. Adding the logic to mkgmap would make more sense I think as it would be immediately and universally applicable. As you say, there may be even more cases beyond the ferry setting where such logic could be applied, and if not accommodated by mkgmap, would need to be re-tagged in OSM. On 17-06-14 05:17 AM, Andrzej Popowski wrote:
Hi Sam,
ferries get class 3 for routing, which is high. They should be easily used in routing when allowed in GPS.
If the problem really is low routing class of service roads, then I see 2 solutions:
Convince OSM mappers to add more tags for "highway=service". This could be for example "service=ferry". Or add any other indication, that these roads carry important traffic, for example include roads in a relation. Then this could be processed by mkgmap.
Second solution would be to try to catch the problem by mkgmap. I think there are more similar cases, where 2 important roads are connected by a link or roundabout with significantly lower routing class. Mkgmap could include following algorithm:
Find all suspicious objects, like highway links, roundabouts, service roads connected to a ferry and analyze other roads connected to this object. If any of these other roads get road_class 3 or 4, then increase road_class of processed object accordingly to 3 or 4.
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