The Main Structure has five hierarchical levels at Population Census times, comprising in ascending order: CDs-SLAs-SSDs-SDs-S/Ts. In non-census years, CDs are undefined and the Main Structure thus has only four levels of hierarchy.
In this structure, CDs aggregate to form SLAs, SLAs aggregate to form SSDs, and this aggregation principle continues up the remaining hierarchical levels. At each hierarchical level, the component spatial units (e.g. SLAs) collectively cover all of Australia (as defined in Chapter 1) without gaps or overlaps.
Detailed tables of the Main Structure are shown in Chapter 15 - The Classification Structures.
(showing three hierarchical levels: S/T-SD-SSD)
- Main Structure - Detailed
(showing four hierarchical levels: S/T-SD-SSD-SLA)