Added linestring geom to curb zone

[InrixParking]

Explain pull request

Curb Zones geometry should be able to be represented as linestrings as well (currently it is restricted to polygon) -- often we know the length of a curb zone but not the "width". Allow type linestring for geometry field under curb zone

Is this a breaking change

• No, not breaking

Impacted Spec

• Curbs

Additional context

Discussed here https://github.com/openmobilityfoundation/curb-data-specification/issues/119

[CLAassistant]

All committers have signed the CLA.

[jacobmalleau]

Adding that CurbIQ currently stores all curb zones in line strings by default, and many cities prefer this visually, so this is a welcome addition.

[mplsmitch]

We will be discussing this at the Feb 25th CDS Working Group meeting. Please review and leave your comments and questions ahead of time.

[schnuerle]

Need to determine if this is a breaking change by not requiring polygons any more. I believe it would be breaking.

So that would mean

1. Add linestring as new field that is optional for 1.1. A linestring option could still be useful, even when you define a polygon shape.
2. Make polygons optional for 2.0 (but still require either a polygon or linestring)

Many people have worked around the issue of not knowing a curb zone width by easily extrapolating geometrically from the line to a rectangle, either of typical width (like 10 feet) or just a small area (like half a foot). The polygon doesn't have to be exact, just representing the zone in some way. An actual detailed width value is an optional field.

[schnuerle]

We will be discussing this at next week's Curb Working Group meeting.

Make sure to look at the lengthy discussion on this topic in the original source issue #119

[schnuerle]

Current suggestion:

Name	Type	Required/Optional	Description
curb_zone_id	UUID	Required	The ID of this Curb Zone.
geometry	Polygon, Linestring	Required	The spatial extent of this curb zone. A new curb_zone_id is required if this geometry changes.

To keep it non breaking:

Name	Type	Required/Optional	Description
curb_zone_id	UUID	Required	The ID of this Curb Zone.
geometry	Polygon	Required	The spatial extent of this curb zone. A new curb_zone_id is required if this geometry changes.
geometry_line	Linestring	Optional	A polyline that defines the curb zone edge in one dimension.