Yet Another Cycling Forum
General Category => The Knowledge => GPS => Topic started by: Panoramix on 10 January, 2010, 11:35:50 pm
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It seems that some German guy has managed to trick Garmin GPS in doing some good routing. It is Mountain bike specific though. Has anybody tried it?
Autorouting « Openmtbmap.org – Mountainbike / Bicycle/ Hiking Maps based on Openstreetmap (http://openmtbmap.org/about/autorouting/)
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That's sneaky! He's taken "avoid toll roads" and reused it to mean "avoid rough stuff". Diabolical cunning!
There is a general preference to route you over trails and cycleways. Streets have lower prioty. However note that the GPS will not take huge detours on trails to avoid a primary or secondary highway – even though they have the lowest priority. Autorouting with my maps is unusable with a motorcar. Use another Openstreetmap implementation instead if you intend to use you car.
Nicely done.
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Interesting. I had not realised that the routing was somehow a property of the maps themselves rather than the software that "reads" them.
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There are a bunch of standard highway types, and they have various routing scores (a fast road scores better than a slow road, for example). Junctions have a similar set of scores.
The software calculates routes to get the best score given its conditions (eg: yes to cycleways, no to footpaths); the highway types are manipulable in OSM because you can make any data tag mean anything in Garmin format.
It's witchcraft!