My goal is to generate a routable cycle map. The idea is that if I generate map dedicated to cycling, I can also generate the routing information only for cycling. I can then tweak the road classes and the speed settings such that I get a route optimized for cycling.
Some questions arise though:
How does the Garmin deal with the road class and the road speed attributes? In the cGpsmapper manual it says that it first looks at the road class and then at the road speed. Somewhere else I found that the routing algorithm will try not to go to a lower road class than the current one while routing. Does anybody know more about this?
Then, what is the difference between car and bicycle routing besides the obvious one that certain roads are not accessible for bicycles or cars? Does it change the EST calculation? Does the Garmin take the road speed into account for the bicycle routing?
This may even depend on the firmware version of the Garmin unit :/.
I tried a “normal” (not specially produced for bikes) routable map on my Legend HCx. What I’ve seen is that the estimated time seems to approximately match the speed of a cyclist on any class of roads, and not at all a car speed.
What I’ve also seen, is that when a street has a “paralell” cycleway, probably because the cycleway has makes some small bends (it is thus a bit longer than the straight street), the routing selects the street and not the cycleway
(I someone has produced a bike-routable map for France, I’d be glad to test if it gives better routing on this case).
What I’ve also seen, is that the routing correctly takes into account if the flag bicycle=yes has been added to a footway or not. It it thus important to add this flag when appropriate, especially when a such way enables significantly shorter routes.
Thanks for that link. I started testing openmtbmap. For the case where cycleway and street are close each other, the algorithm does not seems to prefer teh cycleway, it still routes on the street.
Nevertheless, I found openmtbmap very interesting.
One remarkable thing is that it displays arrows for one way streets, which is usefull cyclists as well for non-cyclist.