[Routing] Fixing routing with tags

[Dave F]

HI
Could you clarify why you  "don't want to use this this road as a 
through road, even though it's legally allowed "

DaveF


On 11/12/2023 11:53, Florian Lohoff wrote:
> Hi,
>
> Prolog:
> Discuss a generic tag for reducing/increasing route-weights/costs regardless
> of other tags.
>
>
> For 10 years i am running Routing Quality Assurance by calculating
> routes every 30 minutes and watching their changes over time.
>
> When i add regions to that monitoring i typically go through
> and fix "static errors" where road taggings cause small side roads
> to be used as shortcuts.
>
> Most of the time fixing tagging on the roads and the shortcut fixes
> the issue. I typically tag maxspeed, lanes, surface, lane_markings etc.
>
> But sometimes i have cases where these tags are not sufficient and i
> dont get the relative weight of the routes to the higher class
> road network.
>
> I am missing a generic tag to influence routing in ways like "dont use
> this road as a through road although legally allowed" e.g. make it
> more expensive in routing.
>
> Examples:
>
> The route uses "Im Kracht" where it should stay on K22 and L775:
> https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=52.2340%2C8.5138%3B52.2381%2C8.4837#map=15/52.2354/8.4993&layers=N
>
> The route uses "Westerweg" but it should stay on K27, L876, L803:
> https://www.openstreetmap.org/directions?engine=graphhopper_car&route=52.2803%2C8.6965%3B52.2890%2C8.7094#map=15/52.2825/8.7106&layers=N
>
>
> Dont get into discussions why one engine gets it and the other doesnt.
> We are not talking about routing engine/profile comparisons. I can
> create such a problem in ANY engine and profile just depending on the
> geometries and tags understood in one or the other engine/profile.
>
>
> So my idea would be to create a tag like **relative_route_cost=** or
> the like which is a float between 0 and 2 where "1" is "use the route
> weight calculated from your route engines physical tag analysis".
>
> So
>
> 0 -> decrease cost of this road to "0%"
> 1 -> Let the cost be the cost of the engines tag analysis
> 2 -> double the cost of the engines tag analysis
>
> This would allow us to directly influence the usage of "shortcuts" or
> through roads used "accidentally".
>
> I would like to not create "routing engine specific" tags like
> **osrm:relative_weight=** or something.
>
> Thoughts?
>
> Flo
>
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