DIFFERENT DEFINITIONS OF URBAN
The Australian Statistical Geography Standard (ASGS) defines and classifies urban areas in several different ways to make a wide range of statistical data available for this important geographic measure.
Urban Centres and Localities (UCLs) provide the most detailed definition of individual urban areas as small as 200 people. They are defined using Statistical Areas Level 1 (SA1s) that meet objective ‘Urban Character’ criteria, including Census population and dwelling density measures. The low population size of some areas means that only Census data is available for the UCLs.
Section of State (SOS) and Section of State Range (SOSR) group the UCLs into broad classes based on population size within each State and Territory. This enables statistical comparisons of differently sized urban centres and the balancing 'rural areas'. For example, what are the differences between people living in Major Cities, with over 100,000 people, compared to people living in rural areas, defined by the rural balance? By grouping the UCLs into these broad classes it is possible to release a broader range of data on this classification.
The Significant Urban Areas (SUAs) represent significant towns and cities of 10,000 people or more. They are based on the UCLs but are defined by the larger Statistical Areas Level 2 (SA2s) which mean they often include some adjacent rural residential settlement. Using SA2s ensures a wider range of more regularly updated data is available for these areas, compared to UCLs where only Census data is available.
The Greater Capital City Statistical Areas (GCCSA) provide the broadest urban extent and are released as part of the Australian Statistical Geography Standard (ASGS): Volume 1 – Main Structure and Greater Capital City Statistical Areas (cat no. 1270.0.55.001). These are designed to reflect the functional extent of each of the eight State and Territory capital cities. This extends beyond the built up edge of the city to include the people who regularly socialise, shop or work within the city, but live in towns and rural areas surrounding the capital city. They are built from Statistical Areas Level 4 (SA4s), which ensures a wide range of ABS data is available, including labour force data.
ABS Maps can be used to compare these different structures to show the different ways that ‘urban extent’ can be measured depending on your needs and the data available.