User:Pelagic/Incubator/Article idea – Australian Statistical Geography Standard

The Australian Statistical Geography Standard (ASGS) is a geospatial division of Australia into statistical areas. It is defined by the Australian Bureau of Statistics (ABS) to report data from the Australian Census and other sources. Succeeding the Australian Standard Geographical Classification in 2011, there have been three editions: 2011, 2016, and Edition 3.

History
ASGS's predecessor the ASGC (Australian Standard Geographical Classification) was first formalised in 1984, based on geographical classifications already in use at the Australian Bureau of Statistics. Twenty-four editions of its specification were issued from 1984 to 2006. Reviews were conducted in 1988 and in 1996–1997, with resulting changes implemented in 1991 and 2001.

Series 1 (1984–1990) and Series 2 (1991–1995) were each updated by issuing replacement pages. The first series was numbered from Edition 1 to 9, and the second from 2.1 to 2.5. From 1996 to 2006, the editions were republished in whole annually, either as stand-alone volumes or as part of three-volume Census sets, and were numbered for the year of issue.

A review of the ASGC and consultation were conducted during the mid 2000s, with a summary of the new proposed standards published in 2007. Mesh Blocks were introduced for the 2006 census, and the first volume of the new ASGS specification was released in 2010. Subsequent volumes were released in following years, with volume 4 in 2012.

Statistical areas
The primary hierarchy consists of mesh blocks (MBs) and four levels of statistical areas, from SA1 to SA4.

Mesh Blocks are the smallest units of aggregation for census data, usually comprised of 30 to 60 dwellings. Their boundaries are designed so that they can be composed together to approximate other spatial divisions such as suburbs, postcode areas, local government administration areas, and electoral divisions.

SA1s (Statistical Areas Level 1) provide fine-grained detail, but with enough people to maintain confidentiality, having populations of around 200–800. SA2s "represent communities that interact together socially and economically", SA3s are regional, and SA4s "represent labour markets and the functional area of Australian capital cities".

Prior to 2011, in the Australian Standard Geographical Classification (ASGC), the five levels in the main structure were: Census Collection District (CD), Statistical Local Area (SLA), Statistical Subdivision (SSD), Statistical Division (SD), and State and Territory (S/T). There was a close relationship between local government areas (LGAs) and SLAs: in 2006, 484 of 667 LGAs (73%) consisted of single SLAs each, with the remainder of the LGAs having two or more SLAs.

Urban areas
Urban centres and localities (UCLs) are formed from SA1s, and are categorised into Sections of State (SOSs) and Section of State Ranges (SOSRs). Rural areas are not assigned to UCLs, thus UCLs implicitly define "urban" versus "rural". Additional structures are defined for Significant Urban Areas (SUAs) and Greater Capital City Statistical Areas (GCCSAs).

Urban centres and localities
An SA1 is classified as "urban" if it exceeds certain population and dwelling density thresholds, or if it is surrounded by urban SA1s. Clusters of urban SA1s (adjacent or having close road connectivity) form localities (population 200–999) and urban centres (population 1000 or more). Adjacent SA1s with defined land-use types "of urban character" are also included. Urban centres having populations of 20,000 or more are combined with connected urban centres within 3km. There are additional definitions for localities with populations over 200 that don't contain any urban SA1s.

These statistically-defined UCLs may cross local administrative boundaries, but are split on State/Territory boundaries. They are distinct from gazetted towns and suburbs, which are covered by a separate State Suburbs definition.

SOS and SOSR
Sections of state (SOSs) are four broad categories of settlement types: 0) major urban, UCs with over 100k population; 1) other urban, UCs with 1000 to 99,999 people; 2) bounded locality; 3) rural balance. Codes 0–3 fully cover the land area of each Australian state; two special codes group data that cannot be assigned to fixed locations: 7 is "Migratory – Offshore – Shipping", and 9 is "No usual address".

Section of state ranges (SOSRs) subdivide SOSs into finer categories based on population. For example SOSR 15 "1,000 to 4,999" is one of five subsets of SOS 1 "other urban". These groupings allow comparisons like all large versus small population centres, or small population centres in the states of Tasmania versus Victoria.

When combined with 1-digit state codes, SOS and SOSR codes form unique 2- and 3-digit identifiers. For example: 21 is Victoria other urban; 215 is Victoria other urban 1,000 to 4,999; 431 is South Australia remainder of state; and 899 is ACT no fixed address. Urban centres and localities are assigned 6-digit codes, of which the first three digits are State+SOS+SOSR. For example, 922002 "Jervis Bay (L)" is in other territories (9) bounded locality (2) 200 to 499 (2). Special UCL codes exist for rural areas that are not part of an Urban Centre or a Locality, such as "631777 Remainder of State/Territory (Tas.)".

Significant urban areas
Significant urban areas (SUAs) have boundaries defined by SA2s, and populations of at least 10,000. They contain at least one Urban Centre (note that UC boundaries are based on SA1s) having a population of 7,000 or more.

For example the 2016 SUA 1005 Bathurst is comprised of two SA2s 103011058 Bathurst and 103011059 Bathurst - East. It contains the urban centre 112002 Bathurst, but not the nearby locality 122119 Perthville (L). The populated centre of Bathurst has over 70 SA1s, whilst the remaining less-populated parts of the SUA have only 4 SA1s. SUA 1018 Lithgow consists of a single SA2 103031070 Lithgow, containing the smaller urban centre 103911 Lithgow and the locality 122092 Marrangaroo (L), corresponding to the city Lithgow and town Marrangaroo.

Indigenous areas
Indigenous localities (ILOCs), areas (IAREs), and regions (IREGs) are intended to facilitate statistical analysis for aboriginal and Torres Strait islander populations.

Remoteness areas
Remoteness Areas reflect "5 classes of remoteness ... based on the Accessibility and Remoteness Index of Australia (ARIA+)". The five classes are: major cities, inner regional, outer regional, remote, and very remote.

Non ABS structures
Non-ABS structures are collections of mesh blocks or statistical areas which approximate boundaries defined by non-ABS bodies.

The following non-ABS structures are based on mesh blocks (MBs):
 * Local Government Areas (before 2016, these were based on Statistical Areas level 1, SA1s; from 2016 they are based on MBs)
 * State Electoral Divisions
 * Commonwealth Electoral Divisions
 * Postal Areas
 * Australian Drainage Divisions
 * Suburbs and Localities (formerly State Suburbs)

In addition:
 * Tourism Regions are based on SA2s (Statistical Areas level 2)
 * Destination Zones are designed to show travel patterns, it is not stated what level of MBS or SAS these are based on.

Local government areas are updated annually, and electoral divisions in years where there has been a boundary distribution. Other structures are updated 5-yearly to coincide with a Census and a new edition of the ASGS.