[OSM-talk-ie] Multi-part roundabouts (Colm Moore)

[Tony Furnell]

Multi-part roundabouts are a bit of a pet hate of mine too Colm.

I tend to only use a "construction line" temporarily and then delete it
afterwards, to avoid cluttering the mapping data. My personal preference,
if it is indeed an option, would be if the roundabouts were not actually
split - and in the instance of a relation joining and leaving a roundabout,
the whole roundabout is then tagged with that relation.

It's not outside the realm of reality that say a person following a road
route by car actually drives around the whole roundabout once anyway, due
to traffic issues or due to missing the turnoff, but I wouldn't necessarily
see that as meaning that the driver has left the route - the roundabout is
after all just a junction, which they join, and then leave. Doing this
would avoid many instances of relation mistakes wherever edits are made,
but I don't know what other side effects this may have.

PS: I agree on the administrative boundaries; ideally they should stay
wherever they were before the roundabout was mapped, usually through the
centre.

--
Tony Furnell




> Date: Sun, 24 Apr 2022 07:03:09 +0000
> From: Colm Moore <colmmoore72 at hotmail.com>
> To: "talk-ie at openstreetmap.org" <talk-ie at openstreetmap.org>
> Subject: [OSM-talk-ie] Multi-part roundabouts
> Message-ID:
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>
> Hi,
>
> Normally a roundabout is drawn with a single way. However, when relations
> for say, bus routes or boundaries are added, the way can be split into
> several parts, as the bus usually will not use the whole roundabout. As
> there are several parts, using the 'round' tool to make sure the roundabout
> is circular (if it actually is circular on the ground) is not possible. My
> previous solution was to add a circle (a 'construction line') to the
> roundabout nodes, use the round tool and add the following tags:
>
> area=yes
> note=Circle for maintaining shape of multi-part roundabout
>
> As there is a certain amount of effort in drawing the circle and making
> sure it includes all nodes, I have saved the construction lines so that if
> the roundabout has additional ways added (e.g. for the triangular traffic
> islands that are common on most roundabouts) or is inadvertently twisted
> out of shape, the round tool can be used again. Example here:
> https://www.openstreetmap.org/way/448599590 - this is currently very
> slightly off circular.
>
> An issue arises in that iD thinks that the above tagging is insufficient
> and now refuses to allow any changes to be saved. JOSM still allows
> insufficiently tagged objects to be saved.
>
> Would anyone have a better solution? There are currently ~102 roundabouts
> tagged in this way, although there may be others that are still irregularly
> shaped. As in the recent discussion about attaching landuse to roads, I am
> not sure that adding a landuse or similar tagging would be appropriate.
>
> Thank you
>
> Colm
>
> PS It is probably best that boundaries go straight through the centre of
> roundabouts and not follow the roadway - most boundaries were laid out
> before roundabouts existed.
>
>
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