Back to practical issues in EV17. Something I did not say yesterday is that a subrelation distinguished itself from the others: La Drôme à Vélo 91 : Le Pouzin - Ancône. This may or may not involve an analysis of how we manage sections that are common with local routes (another possibility being that this is an alternative route that should not be in EV17).
If it’s signed as EuroVelo it would be an alternative part. There’s the need of local knowledge, because it’s not mentioned in the ViaRhôna stages. It’s not included in the GPX files, so I would not include it.
There was a second one, shorter that you seem to have integrated into Tournon-sur-Rhône -Valence (the part on both sides of the Rhône). It was a separate relation before, about 8 km long.
Something I learned from @Idrizza: the charter of EuroVelo discourages branches and alternative routes. It would definitely be an argument for removing.
During years, EV17/ViaRhona between Valence and Avignon has been in a transitory state with interim itineraries on both sides of the Rhone, i.e. one on the right and one on the left side at the same time, and documented so on the ViaRhona website. Today, there is only one route in this section signposted both as ViaRhona and EV17. However, there may still subsist remains of the interim routes in OSM and on various websites.
I rode this section in June 2023 and if I remember well, the EV17 relations correspond to the signposted route except around Charmes where the track from the EV website is correct.
Well there you have it. My only quibble is that stripping out the prefix – in other words, parsing the number out of the ref – shouldn’t be something that data consumers are forced to do, since it leads to so many edge cases. For example, it shouldn’t be necessary to know that “EV” can be stripped from the beginning of a ref, but not the “K” in K2, the “Y” in Y1, the “EW” in EW5, or the “A” on either side of A1A. It would get even more complicated if, seeing the “EV” on EuroVelo routes, mappers decide to prepend network-based abbreviations to these routes too. In any case, it sounds like the “EV” will be omitted from the EuroVelo refs for multiple reasons anyhow. 
I verified and corrected the sections Valence - Le Pouzin and Le Pouzin - Châteauneuf. Both stages are identical to the gpx tracks from ECF except some minor divergences due to recently constructed cycleways. I did not touch tagging and structuring of relations, just removed/added ways.
La Drôme à Vélo is an alternative route for the ViaRhôna route (according to Piste cyclable le long du Rhône en Ardèche : La Voulte / Viviers - ViaRhôna), but not for the EV17. ViaRhôna is only a european route, it doesn’t have a national ref number in our national bike routes scheme. Even though, it still has some freedom to publicize alternate routes on its national website, but they can’t be signed with EuroVelo signs, therefore can’t be part of EV17 relation or EuroVelo website.
I think they should be part of ViaRhôna relation with an alternate role.
On the ref topic, we will have a problem:
EuroVelo 17 : network = icn, ref = 17, cycle_network = EuroVelo
ViaRhôna : network = ncn, ref = ???, cycle_network = ???
According to the french national bike routes scheme (SNV), ViaRhôna ref should be 17, and cycle_network should be EuroVelo. It raises an issue, as it would mean that two different relations would have the same ref and cycle_network values, only being distinguished by their network tag. What can we do about it?
It won’t be an issue for the swiss Route du Rhône as it has a separate numbering in their national scheme.
Interesting. Each operator has a framework with one or more networks/systems, and references within these networks/systems?
If it can’t be signposted with EuroVelo signs, what makes it part of the EuroVelo network? Alternatively, could a more specific cycle_network value or an operator tag help to distinguish this route from the EuroVelo routes that are signposted as such?
The ViaRhôna is signposted with EuroVelo signs, it’s the alternate route La Drôme à Vélo that can’t be.
ViaRhôna could have cycle_network = Schéma National des Véloroutes (or “SNV”), but it would be redundant with network = ncn. I don’t know what would be the best solution.
@StC yes, each NECC has its own system. In France EuroVelo routes are by default part of the national scheme, under their european identifier (cf. https://www.velo-territoires.org/wp-content/uploads/2022/04/JALRIC-IDD.pdf page 16). I don’t know the swiss scheme, but according to swissmobile, it doesn’t seem to have an european category, only national, regional and local.
Don’t tempt us 
We could go for network:name=Schéma National des Véloroutes and network:interest=national (or something similar to represent its importance/popularity)
The latter doesn’t need a ref=.
We have something similar in the UK - although the National Cycle Network is made up of numbered routes, there are also named NCN routes such as the Way of the Roses and the C2C. These don’t need a ref=. (In reality, the “Must Show Up On OpenCycleMap” crowd have added a bogus one: https://www.openstreetmap.org/relation/1761952)
The “ref” used on signs for that is like this:
Surely there must be Unicode for those symbols 
I have removed it from EV17 and left it in ViaRhôna.
I am pondering the concrete application of the same methods to the Swiss part (it’s easy to revert), so as to see if it makes sense at all. I suspect the result will raise the question of branches, because we’ll have two areas with separate branches : the Geneva Lake and the Camargue.
Done. ECF’s EV17 is now a sequence of daily sections that are shared with Veloland Schweiz’s route 1 and Vélo&Territoire’s national/european route 17. Alternative and approaches are only present in the national versions, as they are not recognized under the EuroVelo charter. I have removed ref and name tags from daily sections (but temporarily left equivalent note tags so as to make life easier in JOSM), and defined the ref and operator tags as discussed above. I have not (yet) defined cycle_network tags for the national versions, because I was not sure what to write exactly.
From there, I see four interesting directions for further work:
- decide whether this “flattened” structure is good
- define
cycle_networkfor the national versions, and explore the idea of convertingcycle_networktonetwork:name(or something similar) and maybeoperatortonetwork:operatoras proposed earlier. - discuss and test how to deal with the branches around Geneva Lake and Camargue: roles, segments, other?
- decide about the
superroutetag if we can converge on something in the thread that deals with it
The key change to the relation members can be seen here - the removal of name and refs, and the addition of from, to and note.
About the operator tag, Vélo & Territoires isn’t the maintainer or operator of this route. The operator would be something like Comité d'itinéraire ViaRhôna, or empty and each stage could have its own operator. The latter would be the truest way to fill this field.
Vélo & Territoires could indeed be a value for a network:operator tag.
For stages’ stage tag, what would be the better way to proceed:
- for the first swiss stages, the value would be the same for EuroVelo
Véloroute du Rhôneand swissRoute du Rhône - for the french stages, the number for Genève - Vulbey stage should be 2 according to France Vélo Tourisme cutting, but 8 if we take into consideration the whole EuroVelo route
Yes, sorry. I knew I was missing something when working on this but could not put my finger on it.
I created a topic on the question of how to tag and number daily sections. I perceive several difficulties, including 1) branches and 2) conflicts of tag values when a daily section belongs to two or more routes with different numbers.
@StC , thank you for your work!
For me: too flat
I would prefer at least one intermediate sectioning with relations with EV-tagging, i.e. ref… with sections. My favourite with current knowledge would be:
- Andermatt - Genève (from the Alps to Lake Geneva)
- Saint-Gingolph - Genève (South of the Lake Geneva to Genève)
- Genève - Lyon (Through the Jura Mountains)
- Lyon - Beaucaire (Direction south to the Mediterranean)
- Beaucaire - Port-St-Louis-du-Rhône (The east side of the Rhône Delta)
- Beaucaire - Sète (The west side of the Rhône Delta)
Where branches meet or where the route branches out there should be a section. Lyon would be a rather good spot to divide the big part in the middle.
These relations should be made of your existing relations only.
For EV17 I see no need to do sectioning at the border between Switzerland and France.