OpenStreetMap

Few details around Semily

Closed 5 months ago by supsup

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• Comment from cehceh 4 months ago

  Hallo supsup,
  making sub-realtions on an via ferrata relation is not an good idea.
  The main relation and also the starting points are broken now; see e.g.
  https://www.xctrails.org/map/map.html?type=allferrata&trail=10588521
  So I would strongly prefer to move the tags in the lines and to remove the sub-relations.
  Greetings
  Matthias

• Comment from supsup 4 months ago

  I see. As for starting point, it is not documented https://wiki.openstreetmap.org/wiki/Tag:via_ferrata%3Dstart . Does it work by description value matching the names of the via ferrata relation? I think I changed that to a name, which made more sense to me.

  Is it common practice to map all via ferratas in a given spot as one relation when they are more theme-park like instead of mainly serving to securely get from A to B? The wiki says route=via_ferrata is still a proposal and "https://wiki.openstreetmap.org/wiki/Proposal:Via_ferrata#Tagging_as_route=via_ferrata_relation" does not specify this (it says all ways should be added to it, but I think that referes to OSM-way's, not real life ways) . To me in this particular case, there are three via ferratas of different difficulty that can be climbed independently (so red, blue and purple - they also have different names [by colour], and different difficulty). Hence there should be three relations?

  I can change it accordingly, I am just not sure what the best practice is.

• Comment from cehceh 4 months ago

  Hi supsup,

  Yes, I know, the tagging of via ferratas is a long-discussed but never conclusively clarified topic.
  At least the mentioned proposal has been accepted in many cases.
  I'm looking at and tagging via ferratas in eastern Germany, France and also the Czech Republic for many years and I am in discussion with other via ferrata mappers (e.g. Arminus, sannorra).

  We use the following approach for routes and relations:
  - Dividing route sections into a relation as soon as different difficulties, elements or variants occur
  - Naming of variants in all sections of this variant
  - always "highway=via_ferrata", if only accessible with equipment
  - always "via_ferrata_scale" at each individual element (variants, emergency exits, bridges, ...) and for the relation (we have mostly considered the more difficult variant, but not bypassable short extreme variants); this tag is evaluated in XCTrails and displayed in color
  - "route=via_ferrata" + "climbing=route" + "type=route" for relations
  - "name=..." for relations and, if known, for the individual sections and variants (also displayed individually in XCTrails)
  - optional "fee=...", "access=..." and "access:conditional=..." for fee obligation, blocking or access only as a customer, seasonal blocking (the latter is displayed in XCTrails with a cross through it depending on the time).

  No standards or best practices are officially available for the starting points. Starting points are also only displayed on maps that actually evaluate this tag.
  The approach is as follows:
  - Only one starting point for the entire relation (i.e. the point at which you decide on one of the variants). This is the point that can then be displayed on overview maps, e.g. as "Via Ferrata Vodní Brána" with a symbol (in such a view, several start symbols very close to each other make no sense)
  - After many tests, I now use the following tags for the starting point, which are not criticized by the quality assurance (Osmose, OSMI, ...) only in this combination:
  description=Via Ferrata... (name)
  via_ferrata=start
  natural=cliff
  sport=via_ferrata
  - in XCTrails the tag "via_ferrata=start" is used as a marker where the symbol goes (otherwise the route direction or altitude).

  In this case I would suggest
  - a single relation with named sections and different difficulties (via_ferrata_scale)
  - Names and also colors (but as far as I know no one displays these on a map) for each section.

  Hope this helps!
  Matthias

• Comment from supsup 4 months ago

  Hm, so if I get it right, when you use "variant", you mean "way" in OSM. "Section" does not map to any concept in OSM - all the ways in a section need to have name (and colour) applied to each of them. I was trying to break down the sections into individual segments according to their difficulty as the in-place map suggests (i only properly did the purple one, note that the map is no all up to date to reality)the : https://imgur.com/a/STGasQY

  I think the current way is a bit of mapping for a renderer (xtrails) and the way I used subrelation makes sense as it maps better to real world than the usage you suggest.

  I have a suspicion the breakage might be due to me moving what is in description to name, I am correcting that now and let's see what it does on xtrails. If it does not help, I can go back to one relation.

  Also, I think all this should be documented in the wiki even if it is still a proposal.

• Comment from supsup 4 months ago

  So the starting point is changed back: https://www.openstreetmap.org/changeset/154452452#map=19/50.61555/15.30877

  does that help (not sure how fast xtrails updates)?

• Comment from cehceh 4 months ago

  XCTrails is updated every 2-3 days; at time I don't see any change.
  Ragardless of XCTrails I see a big problem in that the main relation is no longer shown completely if I call https://www.openstreetmap.org/relation/10588521 (only one sub-relation is now shown). But such links I and others use for reference to the complete via ferrata which is no longer possible in the case of so called "super relation".
  As far as I know, these are actually only used for very long and complex routes (traffic connections, long-distance cycle paths, ...).
  As far as I can see, your enhancement mainly concerns the color coding of the routes. Why not define the color as a property of the individual segments?
  In this respect, I would very much welcome a return to a simple relationship :-)

• Comment from supsup 4 months ago

  Ok, I put the individual ways into the parent relations and kept the subrelations for the three individual sections.

  frankly, I still think this is https://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer

  and xctrails (and also openstreetmap.org) should be fixed to support superrelations. There is a segment that the purple and red section share, so colour cannot be applied correctly to that way. The main change was actually breaking the purple way into its constituents accroding to the schematic map on-site (picture is linked above) plus aligning everything in the area to a more proper spot.

• Comment from supsup 4 months ago

  Ok, I documented https://wiki.openstreetmap.org/wiki/Tag:via_ferrata%3Dstart

• Comment from supsup 4 months ago

  And also the relation: https://wiki.openstreetmap.org/wiki/Tag:route%3Dvia_ferrata

  feel free to edit both. But as there seems to be some form of consensus, it should be in the wiki in my opinion.

• Comment from cehceh 4 months ago

  Thank you very much!
  I'll check it out when we get back from the Alps in a couple of weeks :-)

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