Include turning_circle(, turning_loop, mini_roundabout)

[westnordost]

In OSM, there are

• highway=turning_circle
• highway=turning_loop
• highway=mini_roundabout

These features all have in common that they can be represented as a circular slub in the road-way at the node position where it is tagged.

On the default mapnik map, the first two look like this.

In the vector-datasource though, they are not included, so it cannot be rendered. I think it would make sense to include it in one way or another because it is useful to see if one can easily turn at the end of dead end street or not.

[nvkelso]

Sounds good! We already have mini_roundabout in the pois layer:

vector-datasource/yaml/pois.yaml

Lines 1354 to 1358 in 767cc23

	- filter: {highway: mini_roundabout}
	min_zoom: 15
	output:
	<<: *output_properties
	kind: mini_roundabout

Can you submit a PR for the other two? Probably a min_zoom of 16 since they are terminal and not in normal traffic flow? Since they don't have names you'd need to also extend the list of highway PONI's in:

vector-datasource/yaml/pois.yaml

Lines 191 to 192 in 767cc23

	- highway: [ bus_stop, elevator, ford, mini_roundabout, motorway_junction, platform,
	rest_area, street_lamp, traffic_signals, trailhead ]

[westnordost]

I do not fully understand the configuration file, but I'll try. Not sure if I have to do more than this:
#1697

[nvkelso]

PR looks great! We can continue work thru the test part more in that PR together.

We're working on the v1.6 milestone and this change would go out in the next Nextzen prod build once that finalizes (but may be a month or two).

[nvkelso]

This all should probably be at zoom 17 not 16 or (and mini_roundabouts at 17 not 15, to match OSM style). They'd still be overstuffed into tiles at zoom 16, though.

18/37.75586/-122.47092

19/37.77639/-122.44749

19/37.90619/-122.55390

[nvkelso]

Well, https://github.com/tilezen/vector-datasource/blob/master/SEMANTIC-VERSIONING.md#major-version-increments says +2 min_zoom change would be major version change so making mini_roundabouts to be 16 instead of 15 (and not 17).

[nvkelso]

Verified.