The SLA is a general purpose spatial unit. It is the base spatial unit used to collect and disseminate statistics other than those collected from the Population Censuses. In non-census years, the SLA is the smallest unit defined in the ASGC. In census years, an SLA consists of one or more whole CDs. In aggregate, SLAs cover the whole of Australia (as defined in Chapter 1) without gaps or overlaps.
SLAs aggregate directly to form the larger spatial units of SSDs in the Main Structure, SRSs in the SR Structure and LGAs in the LGA Structure (see diagram 3, Chapter 1). SSDs in turn aggregate to form the larger spatial units of S Dists in the S Dist Structure (see diagram 3, Chapter 1). Therefore, the SLA is the common denominator which integrates the four classification structures in use in both census and non-census years.
In this edition of the ASGC, there are 1,353 SLAs in Australia including one SLA for each of the three Territories of Jervis Bay, Christmas Island and Cocos (Keeling) Islands.
SLAs are listed in the table - Alphabetic List of LGAs and SLAs within States/Territories - in Chapter 13.
Delimitation of SLAs
SLAs are based on the boundaries of incorporated bodies of local government where these exist. These bodies are the Local Government Councils and the geographical areas which they administer are known as Local Government Areas (LGAs). In the Northern Territory, an incorporated administrative body gazetted under the Northern Territory Local Government Act can take the form of a Community Government Council (CGC). Where there is no incorporated body of local government, SLAs are defined to cover the unincorporated areas.
The delimitation criteria for SLAs are as follows:
the SLA Albury (C) corresponds to the whole LGA of Albury City in New South Wales. In the 2001 Edition of the ASGC, 454 of the total 1,353 SLAs, approximately 34%, equate with a whole LGA while approximately 73% of LGAs equate with one SLA.
- An LGA is an SLA if:
- the LGA fits entirely within an SSD; and
- the LGA is broadly similar in size, economic significance and user needs for statistics to other LGAs in Australia.
the LGA of Calliope Shire in Queensland is split into two SLAs: Calliope (S) - Pt A and Calliope (S) - Pt B because it is split by an SSD boundary. The LGA of the City of Brisbane is split into 163 SLAs generally based on suburbs.
- An LGA forms two or more SLAs when the two conditions above are not met. This can occur when:
- an LGA is divided by the boundary of one or more SSDs. The LGA is split into two or more SLAs each of which falls within the relevant SSD; or
- an LGA is substantially different in size, economic significance and user needs for statistics to other LGAs. The LGA is split into two or more SLAs which generally correspond to one or more suburbs (as occurs in the predominantly urban LGA of the City of Brisbane) or other areas of interest.
Example: currently, only the SLA of Coomalie (CGC) is defined on this basis.
- In the Northern Territory, an SLA can be the administrative area of a CGC if:
- the CGC is broadly similar in size and statistical significance to the other SLAs in the Northern Territory; and
- there is a significant user need for separate statistics.
- For those parts of Australia which are not administered by incorporated local government bodies, an SLA is an unincorporated area. Unincorporated SLAs cover the following areas:
- unincorporated on-shore area(s) and/or off-shore island(s) in an SSD;
Petermann and Tanami in Central NT SSD in the Northern Territory.
Unincorp. Pirie is an unincorporated SLA in the Pirie SSD in South Australia;
Unincorp. Islands is an unincorporated SLA in North West SSD in Queensland.
- that part of an unincorporated area which is considered of sufficient economic significance as to warrant the formation of a separate SLA;
The naming conventions for SLAs are as follows:
- Off-Shore Areas & Migratory SLAs, formed for census purposes for all S/Ts except the Australian Capital Territory and Other Territories to encompass off-shore, shipping and migratory CDs (off-shore, shipping and migratory CDs are explained in Chapter 2);
- the entire area of the Australian Capital Territory. Each SLA is either a suburb, a locality or the non-urban area of an SSD; and the unincorporated part of the Northern Territory. In some SSDs (e.g. Daly, Bathurst-Melville) the entire area is covered by one unincorporated SLA. In other SSDs (e.g. East Arnhem), the unincorporated area is split into several SLAs to distinguish an economically significant town (e.g. Nhulunbuy), island (e.g. Groote Eylandt) or administrative region.
Ballina (A) - New South Wales Area
Queenscliffe (B) - Borough
Liverpool (C) - City
Coomalie (CGC) - Community Government Council
Mid Murray (DC) - District Council
Roxby Downs (M) - Municipality
Murray Bridge (RC) - Rural City
Broome (S) - Shire
Roma (T) - Town
- An SLA which is a whole LGA adopts the name of the LGA including its LGA status as a suffix. Thus, Northam (S) and Northam (T) in Western Australia are separate SLAs. The various LGA types currently in use by States and the Northern Territory are specified in Chapter 3.
the LGA of Stirling (C) in Western Australia is split into three SLAs:
Stirling (C) - Central
Stirling (C) - Coastal
Stirling (C) - South-Eastern
- An SLA which is part of an LGA may adopt a hyphenated name the first part of which is the name of the LGA.
the LGA of the Municipality of Latrobe in Tasmania is split into two SLAs:
Latrobe (M) - Pt A
Latrobe (M) - Pt B
- If the name includes - Pt A, - Pt B, or - Pt C, this indicates the SLAs were formed by splitting an LGA between two or more SSDs (see example below). In this case, - Pt A usually denotes the more urban part of the split LGA.
the LGA of the City of Brisbane in Queensland is split into 163 SLAs, including:
- An SLA which is part of an LGA may adopt a locality or suburb name.
West Arnhem (in Northern Territory)
Bruce (in Australian Capital Territory)
Unincorp. Far West (in New South Wales)
- An SLA which covers an unincorporated area does not contain LGA type. In New South Wales, Queensland and South Australia the SLA name may include Unincorp.
City (Queensland and Australian Capital Territory)
City - Inner (Queensland and Northern Territory)
City - Remainder (Queensland and Northern Territory)
Kingston (Queensland and Australian Capital Territory)
Oxley (Queensland and Australian Capital Territory)
Red Hill (Queensland and Australian Capital Territory)
West End (Townsville (C) and Brisbane (C))
The coding conventions for SLAs are as follows:
- A small number of SLA names are duplicated across S/Ts and one SLA name is duplicated within an S/T. These names become unique when used in conjunction with SLA codes.
Barraba (A) 0400 (in New South Wales) (S/T code 1)
Barcaldine (S) 0400 (in Queensland) (S/T code 3)
- SLAs are identified by four-digit codes. These codes are unique only within an S/T. For unique Australia-wide identification the four-digit SLA code must be preceded by the unique one-digit S/T code.
Ashburton (S) 0250 (in Western Australia)
- The fourth (last) digit of the SLA code indicates the following:
- 0 means the SLA is a whole LGA.
Sorell (M) - Pt A 4811 (in Tasmania)
Sorell (M) - Pt B 4812 (in Tasmania)
- 1–8 means the SLA is part of an LGA.
Bruce 0729 (in Australian Capital Territory)
Off-Shore Areas & Migratory 9779
Within each S/T, SLA codes are in the range of 0001–9990; codes ending with 99 and those within the range of 9991-9999 have been reserved for special purposes (see Chapter 9).
- 9 means the SLA is either an unincorporated area, an Off-Shore Areas & Migratory SLA or an undefined category (see Chapter 3, Chapter 2 or Chapter 9, respectively).
- In the Main Structure, SLA codes are arranged in ascending numerical order within an SSD. Gaps have been provided between the codes for future expansion or change.