[Tagging] Structured approach to the multi-value discussion
marc.gemis at gmail.com
Thu Feb 25 09:46:02 UTC 2016
I think Colin Smale already set up such a page, see Examples on 
This was part of a longer discussion earlier this year 
Some examples that were mentioned in the thread are missing I think:
e.g. turn:lanes and opening_hours.
On Thu, Feb 25, 2016 at 10:32 AM, markus schnalke <meillo at marmaro.de> wrote:
> I like to suggest the following structured approach to tackle
> the multi-value (MV) topic:
> Phase 1: Are MV necessary?
> First, collect examples of seemingly necessary MVs in a wiki
> page. Classify them as ordered and unordered MVs. Discuss
> alternative tagging possibilities, which don't need MVs, for
> these examples. Try to figure out if MVs are rare or common.
> Discuss the variants of name=* separatly because they are most
> After the situation is clearly laid out, the community should
> agree if (ordered, unordered, both, no) MVs are necessary.
> If they are considered unnecessary, goto Phase 4.
> If they are considered necessary, goto Phase 2.
> Phase 2: Implement MV in the key- or in the value-domain?
> MVs can be implemented in the key-domain (e.g. _1 suffix) or
> in the value-domain (semicolons), or multiple identical keys
> could be allowed (only for unordered MVs). Discuss these three
> approaches, without discussing concrete implementations (e.g.
> whether _1 or %1 or whatever should be used). This discussion
> will also have to balance between a user burden (value-domain)
> and a programmer burden (key-domain). This might depend on the
> assumption if MVs are a rare thing or if they are common.
> Without wanting to stress the already questioned voting
> procedure even more, but normally, one would want to ask for
> agreement of the community here as well.
> If multiple identical keys should be allowed, goto Phase 4.
> If MV should be implemented in the value-domain, goto Phase 3.
> If MV should be implemented in the key-domain, goto Phase 3.
> Phase 3: Which separator to use?
> Key-domain: Decide how to separate the key's name and the
> unique suffix. Furthermore one should discuss what suffixes
> should be used.
> Value-domain: The semicolon seems to be the accepted separator
> in this case, but the whitespace after the separator might
> A relevant aspect in this discussion seems to be if these
> suffixes or separators are supposed to be presented to the
> user or hidden and automatically handled by the interface
> Goto Phase 4.
> Phase 4: Transition plan
> At this point, all decisions were made and the community
> agrees if and how MVs should be handled. Now, the transition
> from the current situation to the desired situation needs to
> be discussed. Depending on the outcome of the above phases,
> the transition could include changing editor software, but
> as well it could include re-tagging current MVs in a non-MV
> way. In any way, the time frame for such changes will be long.
> I suggest, that these phases are processed one after each
> other, because otherwise we will hardly agree on the ``higher
> levels''. Thus, now we should start to focus on phase 1 only.
> The different opinions that will likely show up there, will
> explain most of the disagreement that makes our current
> discussions, which mix all in one, so difficult, I am sure.
> It is already valuable if we could agree in phase 1 although
> we might not agree in phase 2. Mixing the discussion all in
> one prevents us from having this success in such a situation.
> I am willing to set up and care for a wiki page for phase 1,
> as such a page seems not to exist yet.
> documents the current state, rather than being a tool to
> support discussing the future.)
> As I'm relatively new to OSM (started mapping about a year
> ago, although my account is older), I don't want to force
> my way of thinking onto the community. In my opinion the
> approach I proposed could help, but if the OSM community
> is successful by doing it differently, I rather stay quiet
> and watch things evolve.
> Hope to help.
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