[Tagging] junction=approach

Joseph Eisenberg joseph.eisenberg at gmail.com
Sat Oct 19 10:06:25 UTC 2019


> 1.	How do I obtain a "ruling" on this, or at least a consensus? Is this the correct forum?

There are no official rulings in OpenStreetMap. Consensus develops
when mappers use and document tags in a consistent way.

This is probably the best forum for this question overall, though you
could also ask the UK community.

> 2.     Is “junction=approach” a useful tag?

As the other mapper @c2r mentioned, it might be somewhat useful to
identify ways that approach a junction without preprocessing.

However, in theory database users can get this information by checking
if the way connects to a roundabout, so it's not necessary to add this
tag in most cases.

> 3.	If not, should it be deleted?

I don't see any need to delete these tags. They are not incorrect. It
would be good to document what it means.

> 4.	Could this be done automatically, or should it be by hand?

You should not mass-edit features unless you adhere to the automated
edits code of conduct. This is relevant whether you do it one junction
at a time or in an automated fashion. See
https://wiki.openstreetmap.org/wiki/Automated_Edits_code_of_conduct

> 5.	Should I amend the Wiki entry for “Key:junction” to deprecate, or warn against this usage?

It might be better to document junction=approach at it's own wiki
page. The page can mention that adding this tag is not usually
necessary.

Since it's fairly rare, it doesn't have to be mentioned specifically
on Key:junction.

- Joseph

On 10/12/19, Peter Neale via Tagging <tagging at openstreetmap.org> wrote:
> Looking around my local area and trying to fix issues flagged by the iD
> editor, I came across a number of road sections on the approach to
> roundabouts, tagged as “junction=approach”.  I can find no documentation in
> the Wiki to support this usage and it seems illogical to me, as “junction=*”
> should specify the type of junction.  The iD editor also objects, stating
> that “junction-=approach” should be a closed way (i.e. an area object).
> An instance of this is https://www.openstreetmap.org/way/205996585.  This
> was created
> in https://www.openstreetmap.org/changeset/15069009#map=14/52.0589/-0.7514,
> so I consulted the original mapper via Changeset comments, saying,
> “....if I have consulted the history and changeset correctly, [this
> changeset] includes a number of instances (e.g.
> https://www.openstreetmap.org/way/205996585) where you have tagged a road
> flare approaching a roundabout with "junction=approach". I can find no
> documentation in the wiki for this tagging and iD raises it as an issue,
> saying that "Junction=approach" should be a closed way (i.e.a 2-D object, or
> area). Could you explain why you tagged it this way? What did you mean by
> the tag? Is it still relevant?”
> Mapper @c2r has responded, ---------------------------“I've always tagged
> roundabout approaches as junction=approach - I must have picked it up from
> somewhere. Looking at taginfo, there's about 1760 ways tagged as such all
> over Europe:
> https://taginfo.openstreetmap.org/tags/junction=approach#map although I
> appreciate that it doesn't appear to be documented - although very little
> was at the beginning when stuff just sort of evolved.
> “The approaches themselves are pretty standard approaches to roundabouts in
> England, i.e. there is typically a raised centre triangular island, for a
> few meters in length where the carriageway flares and separates from the
> centre. It is not an area. I'd always assumed junction=approach was used as
> a shorthand to prevent navigation software deciding that a U turn at the
> gore was acceptable, without needing to actually specify it as such.
> “I'm not really bothered one way or another as to whether it remains as
> being a tag or not; whether it is relevant depends on whether it is useful
> to renderers or to navigation software. However, with the advent of mass
> aerial imagery and critical mass, I'm not as involved in OSM mapping as I
> was years ago when GPS traces were needed, although still add the occasional
> POI/correction so am active in that regard.
> “I'd suggest asking for a ruling from the powers that be. It'd presumably be
> easy to strip the lot from the database programatically if they weren't
> required/of use.”-----------------
> Advice please.
> 1. How do I obtain a "ruling" on this, or at least a consensus? Is this the
> correct forum?2.     Is “junction=approach” a useful tag?3. If not, should
> it be deleted?4. Could this be done automatically, or should it be by
> hand?5. Should I amend the Wiki entry for “Key:junction” to deprecate, or
> warn against this usage?
> Regards,
> Peter
>
>



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