CHAPTER 1 INTRODUCTION
PURPOSE
The main purpose of the Australian Standard Geographical Classification (ASGC) and the Census Geographic Area Classifications is to provide a framework for the collection and dissemination of geographically classified statistics. This publication briefly describes all of these classifications but provides details only on the Census Geographic Areas.
Full details of the ASGC structures are provided in Statistical Geography Volume 1 Australian Standard Geographical Classification (ASGC) (cat. no. 1216.0) and Statistical Geography Volume 3 Australian Standard Geographical Classification (ASGC) Urban Centres/Localities (cat. no. 2909.0).
ASGC
The ASGC is the primary geographical classification used by the ABS. It provides a common framework of statistical geography in both census and non-census years thereby enabling the production of statistics which are comparable and can be spatially integrated. It is a hierarchical classification system consisting of seven interrelated structures each designed to serve a specific purpose. The spatial units of some structures (the Main, Statistical Region, Section of State and Remoteness) aggregate to cover the whole of Australia, while the remaining structures (the Local Government Area, Statistical District and Urban Centre and Locality) cover only a part of Australia.
SPATIAL UNITS OF THE ASGC
The spatial units of the ASGC are as follows:
- Census Collection District (CD);
- Statistical Local Area (SLA);
- Statistical Subdivision (SSD);
- Statistical Division (SD);
- State and Territory (S/T);
- Australia;
- Statistical District (S Dist);
- Local Government Area (LGA);
- Statistical Region Sector (SRS);
- Statistical Region (SR);
- Major Statistical Region (MSR);
- Urban Centre/Locality (UC/L);
- Section(s) of State (SOS); and
- Remoteness Area (RA).
CENSUS GEOGRAPHIC AREAS
The Census Geographic Areas described in this publication have been created so that census data may be made available for commonly used geographic areas other than those found in the ASGC. Census Geographic Areas are defined only in a census year. All Census Geographic Areas, with the exception of the Place of Work areas, are formed by an aggregation of whole CDs. The CD is the smallest spatial unit of the ASGC and is also only defined in a census year.
For the 2006 Census, the Census Geographic Areas are comprised of six separate classifications and spatial units as follows:
- Commonwealth Electoral Division (CED);
- State Electoral Division (SED);
- Postal Area (POA);
- State Suburb (SSC);
- Australian Indigenous Geographical Classification (AIGC); and
- Place of Work (POWP)
SUMMARY TABLES
The following table summarises the various ASGC structures and their component spatial units.
TABLE 1, SUMMARY OF ASGC STRUCTURES |
|  |
| ASGC Structure | Hierarchical Levels | Component Spatial Units | Covers whole of Australia? | |
| |
| Local Government Area | 4 | CD,SLA,LGA,S/T(a) | No | |
| Statistical District | 4 | CD,SLA,SSD,S Dist(b) | No | |
| Main | 5 | CD,SLA,SSD,SD,S/T | Yes | |
| Statistical Region | 6 | CD,SLA,SRS,SR,MSR,S/T | Yes | |
| Section of State | 3 | CD,SOS,S/T | Yes | |
| Remoteness | 3 | CD,RA,S/T | Yes | |
| Urban Centre/Locality | 2 | CD,UC/L(c) | No | |
| |
| (a) Only that part of the S/T which comes under the responsibility of an incorporated Local Government Council. (See Chapter 3 p. 19). |
| (b) Areas covered by S Dist only |
| (c) Areas covered by UC/L only |
The following table summarises the number of ASGC spatial units and Census Geographic Areas.
TABLE 2, COUNTS FOR AUSTRALIAN STANDARD GEOGRAPHICAL CLASSIFICATION AND CENSUS SPECIFIC GEOGRAPHIC AREAS |
| |
| Spatial Unit | NSW | Vic. | Qld. | SA | WA | Tas. | NT | ACT | OT(a) | Aust. | |
Australian Standard Geographical Classification (effective 1 July 2006) | |
| |
| S/T | State/Territory | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 | |
| SD | Statistical Division(b) | 13 | 12 | 14 | 8 | 10 | 5 | 3 | 2 | 2 | 69 | |
| SSD | Statistical Subdivision(b) | 51 | 46 | 39 | 21 | 29 | 9 | 12 | 8 | 2 | 217 | |
| SLA | Statistical Local Area(b) | 200 | 210 | 479 | 128 | 156 | 44 | 96 | 109 | 4 | 1 426 | |
| No. SLAs in Capital City SD | 64 | 79 | 220 | 55 | 37 | 8 | 41 | 108 | - | 612 | |
| LGA | Local Government Area(c) | 153 | 80 | 159 | 71 | 143 | 30 | 38 | 1 | 1 | 676 | |
| S Dist | Statistical District(d) | 14 | 8 | 10 | - | 4 | 2 | - | 1 | - | 36 | |
| MSR | Major Statistical Region | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 14 | |
| SR | Statistical Region | 22 | 14 | 13 | 6 | 7 | 1 | 1 | 1 | 1 | 66 | |
| SRS | Statistical Region Sector | 25 | 14 | 29 | 6 | 7 | 3 | 2 | 1 | 2 | 89 | |
| CD | Collection District (Above CD counts include all Miscellaneous CDs)(b) | 11 966 | 9 310 | 7 672 | 3 246 | 4 370 | 1 068 | 510 | 547 | 15 | 38 704 | |
| No. CDs in Capital City SD (Capital City CD counts include Miscellaneous CDs where applicable) | 6 746 | 6 325 | 3 075 | 2 193 | 2 911 | 389 | 195 | 533 | - | 22 367 | |
| RA | Remoteness Area(b) | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. | n.a. | |
| SOS | Section of State(b) | 5 | 5 | 5 | 5 | 5 | 5 | 4 | 3 | 4 | 41 | |
| UC/L | Urban Centre/Locality | 524 | 350 | 364 | 162 | 179 | 105 | 66 | 2 | 3 | 1 755 | |
Census Specific Geographic Areas (effective 8 August 2006) | |
| |
| CED | Commonwealth Electoral Division(b)(e)(f) | 51 | 38 | 29 | 12 | 16 | 6 | 3 | 3 | 3 | 159 | |
| SED | State Electoral Division(b)(e) | 94 | 89 | 90 | 48 | 58 | 25 | 26 | 3 | 2 | 435 | |
| SSC | State Suburb(e)(g) | 2 593 | 1 498 | 1 965 | 877 | 953 | 404 | 69 | 103 | 2 | 8 464 | |
| POA | Postal Area(e)(h) | 610 | 654 | 432 | 325 | 339 | 108 | 29 | 26 | 4 | 2 515 | |
| IREG | Indigenous Region(i)(j) | 8 | 3 | 9 | 4 | 9 | 2 | 8 | 1 | 2 | 45 | |
| IARE | Indigenous Area(j)(k) | 146 | 46 | 128 | 34 | 92 | 17 | 73 | 3 | 4 | 542 | |
| ILOC | Indigenous Location(j)(k) | 236 | 61 | 161 | 62 | 145 | 29 | 146 | 3 | 4 | 846 | |
Miscellaneous CDs (effective 1 July 2006) | |
| |
| Water CDs | 54 | 5 | 3 | 3 | 7 | 1 | 11 | 11 | - | 95 | |
| Nil CDs | 5 | 62 | 62 | 17 | 194 | 2 | 34 | 7 | - | 383 | |
| Off-Shore CDs | 1 | 1 | 1 | 1 | 1 | 1 | 1 | - | - | 7 | |
| Migratory CDs | 1 | 1 | 1 | 1 | 1 | 1 | 1 | - | - | 7 | |
| Shipping CDs | 10 | 8 | 15 | 10 | 16 | 10 | 5 | - | 3 | 77 | |
| |
| - nil or rounded to zero (including null cells) |
| (a) Other Territories (OT) includes the territories of Cocos (Keeling) Islands, Christmas Island and Jervis Bay. |
| (b) For each state and the NT and OT, a code for Off-Shore, Shipping and Migratory CDs have been included. |
| (c) Includes the LGA 9399 Unincorporated State/Territory for each State/Territory. |
| (d) Statistical Districts can cross State/Territory borders. For the purposes of the above table, Statistical Districts that cross State/Territory borders are counted in each State/Territory (NSW 3, Vic 1, Qld 1, ACT 1), but are counted only once in the Australia total. |
| (e) These Geographic Areas are derived on a 'best fit' basis of CDs to externally determined boundaries. They are often referred to as CD Derived Areas. |
| (f) The ACT Electoral Division of Fraser includes Jervis Bay and is counted in ACT and OT. The NT Electoral Division of Lingiari includes Christmas Island and Cocos (Keeling) Islands and is counted in NT and OT. Each is counted only once in the Australia total. |
| (g) State Suburb counts include an 'unclassified' suburb that occurs in each State/Territory where suburb boundaries do not cover the whole state. It also includes Off-shore, Shipping and Migratory CDs. |
| (h) Includes the ABS assigned 'dump' postal area for each state (x999), 2699 for the ACT, and 0899 for the NT. Postal Area boundaries may cross State/Territory borders and can be counted more than once in individual State/Territory figures but only once in the Australia total. |
| (i) The Indigenous Region, 01 'Queanbeyan', crosses State/Territory borders and as such is counted in NSW and OT. It is counted once only in the Australia total. |
| (j) For each State, the NT and the OT a code for Off-Shore, Shipping and Migratory CDs has been included. |
| (k) Jervis Bay Territory is incorporated in a NSW Indigenous Area and Indigenous Location. This Indigenous Area and Indigenous Location are counted in OT as well as in NSW. They are counted only once in the Australia total. |
| 2006 Census fact sheet |
| n.a. Counts not available at time of release. |
CENSUS GEOGRAPHIC AREAS STRUCTURAL CHART
The diagram below shows how the Census Geographic Areas relate to each other and to the ASGC.
PRINCIPLES OF THE CENSUS GEOGRAPHIC AREA CLASSIFICATIONS
Census Geographic Areas are constructed so that they fulfil practical user needs for spatial statistics while also conforming to general classification principles.
Classification principles
Census Geographic Areas are constructed according to the basic classification principles that members within one class are of the same type, classes are uniquely defined so as to be mutually exclusive and, in total, the members in each class cover the entire class.
As a result, the geographical spatial units of each of the Census Geographic Areas are:
- of the same type, delimited by well-defined criteria;
- defined by aggregation of whole CDs (except for Place of Work);
- uniquely identified by codes and referenced by names (except Postal Areas);
- mutually exclusive; and
- in aggregate cover the whole area to which that hierarchy applies.
Boundary formation
The Census Geographic Areas are designed for the provision of Census data for areas which are not appropriate for inclusion in the ASGC but which have particular significance for some groups of data users. Place of Work and the AIGC are defined to facilitate the use of work-related transport data and Indigenous statistics respectively. The remaining Census Geographic Areas are approximations of administrative areas defined by an organisation other than the ABS. For example, CEDs are an approximation of the Electoral Divisions defined by the Australian Electoral Commission and POAs are an approximation of the postcodes defined by Australia Post. The Census Geographic Area is an approximation for use with census data but the original area as defined by AEC or Australia Post, etc, remains the official definition.
The CD is the smallest building block which serves the classification structures of both the ASGC and the Census Geographic Areas (see diagram 1, Chapter 1). Thus, Census Geographic Areas which approximate official administrative areas are created by allocating whole CDs to a particular official administrative area. A CD can only be assigned to one area in each Census Geographic Area classification. Thus, when CDs are completely contained within an official administrative area, they are allocated to the corresponding Census Geographic Area. However, when a CD shares area with more than one official administrative area, a decision must be made as to which area the CD should be allocated. This allocation is made on the basis of the administrative area which contains the majority of the CD's population. This means the ABS representation of the official administrative area will not match the exact size and shape of the official unit. The term used to describe the resulting ABS defined area is 'CD derived'. Once the spatial units have been derived, it is possible to provide census data for them by aggregating data for their component CDs.
User needs
The official administrative areas which are approximated in the Census Geographic Areas are chosen on the basis of demonstrated demand for statistics for these areas. However, other geographic areas not included in the Census Geographic Areas or the ASGC may be accommodated through customised services available for census data.
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