[Tagging] Roundtrip and closed loop in relations

[Peter Elderson]

For PT, roundtrip is not an attribute of the route, it's a type of ticket or it's what you use the transport for. You can do a roundtrip on a circular line, but also on non-circular lines or mostly non-circular with a loop at the end, whatever. To express that a PT route is circular, I think the term circular would be better than roundtrip. 

For hiking|foot routes, exception is the rule when it comes to branches, alternatives, excursions, approaches and shortcuts. For me roundtrip on a walking route relation means: when you keep following the main route markings, it takes you back to where you begun. This does not exclude any alternatives, such as optional extra loops or a common approach/exit route at a starting point. Only roundtrip=yes is needed here, if not present assume it's not a roundtrip. Note that many trails consist of a number of linear routes, together making for a roundtrip. I tag roundtrip=yes only on the parent route relation. Loop or circular would also be just fine, but I see no reason to change existing tagging here.

Question: who wants to know if a route is a circular route/loop/roundtrip? Is it the map user? No, (s)he can see it on the map. Is it important for routing and navigation? I can't see how, but there are experts on this list who know more about this. So far I know of only one application: categorisation/filtering of trips in order to present the user a choice between roundtrip walks or linear walks. The roundtrips were actually meant to be daytrips, and linear walks were to be presented as " long distance walks", but a separate category long distance roundtrips could be deducted from the data, I guess.

Question: who wants to know if a route is actually a closed loop without any branches?
What do you need this information for? So far, I know one application: if a route is tagged as a closed loop, e.g. with closed_loop=yes, and it's not complete or interrupted somewhere, you can detect that with a checking tool. It would be a sort of fixme, then. Most routes I maintain would not profit from that. 


FrGr Peter Elderson

> Op 21 dec. 2019 om 15:31 heeft marc marc <marc_marc_irc at hotmail.com> het volgende geschreven:
> 
> I always thought that routrip=yes was an alternative when there is no
> start and end point to enter in from=* to=* key.
> Otherwise circular routes with a known start/end point can enter
> as from=A via=B to=A.
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