Improve rendering of loops and roundabouts

[Stephen214]

Currently, circular road features are not rendered well, which seems to be contributing to mappers marking features with the wrong tag (primarily mini_roundabout) to affect rendering. Specifically:

1. highway=turning_loop is rendered the same as highway=turning_circle; it is missing the island that distinguishes the two.
2. junction=roundabout on a node is not rendered at all.
3. The symbol for a mini-roundabout is not intuitive.

I propose the following:

1. Add a black* dot in the middle of highway=turning_loop.
2. Render junction=roundabout as highway=turning_loop plus directional arrows.
3. Render highway=mini-roundabout as highway=turning_circle plus directional arrows.

Directional arrows would default to anti-clockwise but reverse if direction=clockwise.

Mockup:
highway=turning_circle (no change)

highway=turning_loop

highway=mini_roundabout

junction=roundabout

• I assume transparent wouldn't work due to rendering of the parent way(s) in the same location, but if it is, that would be preferred.

[pnorman]

highway=mini_roundabout

This implies a default directionality, if we have arrows they should only be if the direction is tagged explicitly.

junction=roundabout

The image is probably too detailed to render cleanly at small size. This might also be an issue with highway=mini_roundabout

[Stephen214]

This implies a default directionality

Per the wiki, the default direction is anti-clockwise.

The image is probably too detailed to render cleanly at small size. This might also be an issue with highway=mini_roundabout

JOSM's roundabout icon is legible at small sizes, and it'd be moreso against the flared background. Or just only show it at zoom levels where it is. However, the most important parts are the flare and (if applicable) the island, which should look fine at any zoom where turning_circle is rendered too.

[boothym]

Since roundabouts have a non-traversable island, shouldn't they be drawn as a circular way rather than be represented by a node? Looking at nodes with junction=roundabout on overpass-turbo, it shows plenty which should either be drawn as a way or tagged as something else. So I don't think we need to change anything.

[polarbearing]

While the wiki allows junction=roundabout on a node, this makes no sense to me, it could always be drawn as a way.

[Stephen214]

Roundabouts SHOULD be drawn as a circular way, but thousands of them aren't, especially smaller ones where it wouldn't be visible except at high zooms anyway.

[BalooUriza]

Not all roundabouts are round, either. I can think of four (in Portland's Ladd's Addition neighborhood) that are diamond shaped...

…

On Wed, Mar 22, 2017 at 11:18 AM, Stephen214 ***@***.***> wrote: Roundabouts SHOULD be drawn as a circular way, but thousands of them aren't, especially smaller ones where it wouldn't be visible except at high zooms anyway. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2535 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACwyhpSeXKEymq9aum4KOXdxQ3TIcOknks5roUm_gaJpZM4LbEVH> .

[Stephen214]

Added some roundabout arrows icons derived from JOSM's at:
https://josm.openstreetmap.de/browser/josm/trunk/images/presets/vehicle/restriction/roundabout_left.svg
https://josm.openstreetmap.de/browser/josm/trunk/images/presets/vehicle/restriction/roundabout_right.svg

These would be useful as-is for mini-roundabouts, and with the addition of an island (svg already available) for full roundabouts. I think they'd work anywhere the current traffic signal icon fits, i.e. even without the road flare.

[Stephen214]

Argh; it ignored my attempt to attach SVG files, and it says it'll take a ZIP of them, but that gets ignored too. How do I share them?