Table 3 Additional metadata elements for 3D city models we include in our ADE

Levels of Detail (LoDs)

This includes the LoDs present in the city model and each thematic module with unique and aggregate counts for each. We support the improved specifications of buildings as developed by Biljecki et al. [3].

Biljecki et al. [3]; Dietze et al. [8]

Semantic Surfaces

The presence or absence of semantic surfaces in objects, e.g. roofs, walls, etc.

Dietze et al. [8]

Textures/Materials

The presence or absence of textures and/or materials in a city model which are representation of object surface characteristics

XLinks

The presence or absence of XLinks in a city model, these are used to share geometry elements between features.

External References

The presence or absence of external references, these are a reference of a 3D object to its corresponding object in an external data set

Thematic Modules

A list of all thematic modules present in a city model, e.g. Building, Transportation, etc.

ADEs

A list of the ADEs utilised in the city model and their corresponding metadata as described in “Implementation” section