Is an empty boundaries array allowed?

[balazsdukai]

Geometries are not obligatory for CityObjects, so we have three valid options:

• { "type": "Building" }
• { "type": "Building", "geometries": [ ] }
• { "type": "Building", "geometries": [ ... ] }

Then, a Geometry object must have a "boundaries" member with an array of vertex indices. But the specs does not explicitly allow or forbid empty arrays, such as "boundaries": [ ].

In my opinion, it does not make much sense to have a Geometry object with empty boundaries, but it can happen. For instance due to a failed procedure that creates the geometry.

Should we consider an empty boundaries a valid or invalid CityJSON?

[hugoledoux]

Good point, I had never thought of this!

I think this can be fixed easily with adding a minItems, see that snippet: https://www.jsonschemavalidator.net/s/6GxMeDl8

[balazsdukai]

👍 this looks good to me, validation works indeed.