[Tagging] Clarification on the role link in route relations

[Minh Nguyen]

Vào lúc 15:20 2022-01-13, Dave F via Tagging đã viết:
> Those roads are *oneway*. The one heading *away* from the route 
> shouldn't be included because it's *not* a link *towards* the route 
> relation.

Your understanding differs from the definition in question, specifically 
the phrase "from and to the route". So far, no one has stepped forward 
agreeing with the definition as stated on the wiki, while most responses 
have expressed surprise and disapproval of it. The wiki page has already 
been amended to cast doubt on itself regarding the role. [1]

All the more reason to toss out the old definition entirely and replace 
it with one more tightly scoped to piste routes (for which this role was 
approved). We can add a note pointing out intentional usage on cycle 
routes in the UK based on the signage you mentioned, if that is in fact 
how it's used there.

If you think the role should be used more widely in other circumstances, 
I think you'd need to make that case more convincingly. Most of the 
other route relation roles have gone through the wiki's proposal process 
or at least enjoyed more enthusiastic support than this "link" role.

> It appears there's nothing wrong with the OSM database in this case, All 
> that's required is a couple of lines on your code to filter the data you 
> don't require.

Filtering out unexpected or nonsensical data is always an option for 
data consumers. But in principle, a relation type should be consumable 
without having to account for exotic, inessential roles. [2] If the 
on-the-ground reality necessitates the "link" role in some cases, then 
so be it, but we need to be able to provide clear guidance about those 
cases so that a mapper doesn't confuse it for a different situation they 
encounter.

[1] https://wiki.openstreetmap.org/wiki/Special:Diff/2245566
[2] https://wiki.openstreetmap.org/wiki/Trolltag

-- 
minh at nguyen.cincinnati.oh.us