[Tagging] Clarification on the role link in route relations

[Minh Nguyen]

Vào lúc 13:40 2022-01-08, Kevin Kenny đã viết:
> On Sat, Jan 8, 2022 at 4:07 PM Minh Nguyen 
> <minh at nguyen.cincinnati.oh.us 
> <mailto:minh at nguyen.cincinnati.oh.us>> wrote:
> 
> On Slack, it came up that there are only a few small regions of the US 
> where route relations have members with the 'link' role, and one of 
> those was the Capital Region surrounding Albany, New York. I was 
> identified as the perpetrator.
> 
> I plead guilty to having started on my journey of creating route 
> relations by a careful reading of the Wiki page describing them.

No worries, this exercise is about clarifying the documentation, not 
arraigning those who adhered to it.

> If the "link" role doesn't mean what it says on the tin, then I haven't 
> that much use for it, although I need to be informed about what to do 
> about slipways that are signed with a route number, but which are 
> joining the route, rather than members of the mainline. I have in mind 
> slipways at surface intersections, rather than motorway link roads, for 
> which proper "destination" tagging at the interchange will probably be a 
> better solution. I don't do all that much motorway mapping in any case, 
> except to repair broken route relations.

I assume you mean the shorter link roads known as "slip lanes" or "turn 
channels" in American English, the ones that are separated by "pork chop 
islands"? They can be tagged with destination:ref and optionally a 
destination_sign relation, just as with a longer ramp if signposted. 
There's no tag to explicitly distinguish slip lanes from ramps, but some 
routers have heuristics based on the way's length or shape.

-- 
minh at nguyen.cincinnati.oh.us