An important concept to understand is the difference between mapping ways and relations. The ways are the physical paths, tracks, and roads. Relations are used to group these into named walking routes. So adding a hiking route sometimes requires two steps - if the ways have not been mapped they need to be added first, and then included in a relation. But in many cases the ways are already in the database and only the second step is needed. Possibly for this data a mixture of both situations will apply.
When you say “they have the data on the trails”, in what form do they have the data and where did it come from originally? For example are they GPS traces collected by individuals when walking? Or is it some kind of central database of GPS traces? Or something more descriptive e.g. “the E8 in Ireland is made up of parts of Irish waymarked ways such as the Beara Way, Kerry Way…”
If the idea is to import to OSM from a database this would likely fall under the Import Guidelines: https://wiki.openstreetmap.org/wiki/Import/Guidelines
In particular you would need to be clear that the data is available under a licence that OSM can use. Again this will depend on where the data came from in the first place. I believe that in France in particular the issue of copyrights around hiking trails has been a problem (referred to in the France section of the first link above).
Unfortunately there doesn’t seem to be a specific forum or mailing list for mappers interested in hiking or outdoor activities (I am open to correction on this, if there is something along those lines that I am not aware of I’d also like to know about it). At some point you will probably want to contact local mappers through country-specific forums or mailing lists, but I realise that doesn’t really work as a first step given that these trails cross so many countries.
I think this message needs to be directed at individual country mailing lists / forums (it will depend on the country which is most popular). In my experience there are a large number of active mappers interested in footpaths and long-distance trails right across Europe. However, much trail mapping is done at a local level rather than surveyed as part of the process of walking the trail which can result in inconsistencies in detail and how current the data might be.
In some cases there exist local associations, OSM Chapters. These exist, and are formally affiliated with OSMF, for: Belgium, Switzerland, Germany, UK, Ireland, France and Italy. Poland has an association but I do not believe it is affiliated yet. I would suggest contacting these bodies because they can: a) inform you of current status in their country and any particular initiatives they already have in place; b) disseminate information to their members & via the most widely used communication mechanism for the country; c) put you directly in touch with active knowledgeable mappers; d) possibly organise shared workshops for ERA people and OSMers.
In addition there is a worldwide conference in Heidelberg this September which may be a good point to meet many people. Session proposals are open: perhaps a session on mapping E-paths would work. France has a very well attended conference to be held in June at Montpellier: this is inexpensive to participate and may bring your group in contact with people who mapped some of the Via Alpina 6 years ago: https://wiki.openstreetmap.org/wiki/ViaAlpina#A_looooong_mapping_party.21.
In the UK, and specifically England & Wales (because the legal situation is different in Scotland & NI), we have a well-developed approach to mapping footpaths (public rights of way) which covers practices of how to map the path, mapping stiles, gates, steps etc, mapping the adjacent countryside to assist navigation etc, trail waymarking. SomeoneElse also maintains a map which is specifically designed to provide information on footpaths, local and long distance trails. In the main we are probably more interested in the local path network because of impending legal threats to the existence of some paths.
Yes, I am well aware that most of the trails are mapped to a high percentage and that is good.
And where they are well mapped, there is no issue.
It is only where we need some assistance to map part of the trails in some countries, we need some assistance.
My question can therefore be concretized to: Will it be convenient to establish a project here or elsewhere, where these experts can meet with the OSM’ers within the geografical areas where we need assistance to map parts of a specific trail.
As alan_gr says above: You will probably want to contact local mappers through country-specific forums or mailing lists.
I think that will be the answer to us, if we need assistance to mapping the outstanding parts.
But please do post here as well. There are lots of OSMers who take an international interest in walking and cycling routes. One of our greatest mappers, Malenki, sadly died while on a walking holiday in Spain a couple of years ago. I think he’d be pleased to see the interest you’re taking in having trails mapped in OSM.
Richard (Euro walking route 2 goes directly past my front door )