The sequence of the component ways in a walking/hiking route relation is irrelevant for a hiker who use a navigation device to walk along the route. Why? How do you walk a walking route with a navigation device? Basically you have two options: A) you have prepared beforehand a GPX track, typically by using a routing/planning tool on a web site. That site does off-line routing for you. During the walk you follow the GPX track on the display of your GPS device (you keep you position on the track on that you see on the screen) B) you use an equivalent navigation process as in (A) but you execute it in real time on the map that you have loaded on your navigation device.
In both cases you use some kind of algorithm that finds for you a (nearly) optimal route from waypoint to waypoint. What does the routing algorithm do? It assigns, from a table that defines your means of transportation, "cost" (or "penalty") per meter to each way on the map and basically finds the "cheapest" connection between consecutive waypoints (in the simplest case there are two waypoints: start and destination for the off-line navigation, and actual position and final destination for the on-line version). The cost for each way type is dependent on your means of transport. In the case of walking the cost for a motorway will be near infinity, with the effect that a hiker will not be routed via a motorway. A perfectly smooth footway will have a very low cost, a bumpy footway will have a bumpiness penalty (you are forced to walk slower) and so on. How are hiking route relations handled? The fact that a specific way is part of a hiking route relation means that it gets a cost benefit with respect to an equivalent way that is not part of it. In this way the algorithm gives preference to those ways that are part of a walking route relation. I's up to designer of the routing cost table, how much advantage she will give to a given type of route; she may want to give a national hiking route a bigger cost advantage in comparison to a local hiking route. This is the basics why the routing algorithm does not "care" at all about the sequence of the ways in the hiking route relation. On Sat, 17 Aug 2019 at 13:08, Peter Elderson <pelder...@gmail.com> wrote: > > > Op za 17 aug. 2019 om 12:31 schreef Andy Townsend <ajt1...@gmail.com>: > >> > but I would like to see one make a plausible navigation route out of >> the E2 Yorkshire relation as it is now. >> >> Where are you going from and where are you going to? Without that >> information "make a plausible navigation route out of the E2 Yorkshire >> relation" makes no sense. >> >> That's exactly the point why you can't use a walking route relation as a > navigational route, unless it has been carefully prepared to be an ordered, > uninterrupted single-chained A2B route. > _______________________________________________ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging >
_______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
