Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Built Environment (hierarchy name)
4. Open Spaces and Site Elements (hierarchy name )
5. open spaces
6. [open spaces by form]
7. gardens (open spaces)
8. [gardens by location or context]

Anotations

Scope note:

Gardens, situated on rooftops, typically in urban areas above private houses or commercial buildings. The depth of soil is limited to keep the weight low and the plants are usually set in tubs or similar containers, but elaborate roof gardens have been constructed with small pools and beds.