ARIA is a geographic accessibility index that aims to reflect the ease or difficulty people face accessing services in non–metropolitan Australia. ARIA measures remoteness in terms of access along the road network from over 11,000 localities to five categories of service centres. Areas that are more remote have less access to service centres; areas that are less remote have greater access to service centres. Accessibility and Remoteness can be seen as two ends of a continuum (Figure 5) which describe the ease or difficulty with which one can access a range of services, some of which are available in smaller and others in larger centres. ARIA is a continuous and comparable index of remoteness that covers the whole of Australia, with variable values ranging from 0 (high accessibility) to 15 (high remoteness).
ARIA measures remoteness, in terms of a composite of road distance from each Australian populated locality to the nearest service centres in five size categories. The population sizes of service centres are taken to reflect the types and choices of services that are located within them.
Service centres were grouped into 5 categories (Table 1). For each category, GIS network analysis was used to calculate the distance travelled by road from each of the populated localities, to the edge of the nearest service centre. An ARIA+ value was then calculated for each of the populated localities.
Table 1 ARIA+ Service Centres
|A||250,000 persons or more|
|B||48,000 – 249,999 persons|
|C||18,000 – 47,999 persons|
|D||5,000 – 17,999 persons|
|E||1,000 – 4,999 persons|
Once the distance measures had been calculated, three additional steps were necessary to produce the final ARIA+ values for each locality. The steps are described below and summarised in Figure 6.
Figure 6 Diagram of the ARIA+ Value Calculation Process
The ABS remoteness structure in the 2001 and 2006 ASGC uses a five class classification scheme for ARIA at the CCD
level. The five ABS remoteness classes, defined at CCD level, are termed Remoteness Areas (RAs). The numeric ARIA
break points and the class descriptions used by the ABS are shown in Table 2. Figure 7 shows the spatial distribution
of the 5 classes of remoteness for Australia.
Table 2 Australian Bureau of Statistics ARIA+ Remoteness Areas (RA) Classification
|ARIA+ Score||ABS Remoteness Areas|
|0 - 0.2||Major Cities of Australia|
|>0.2 - 2.4||Inner Regional Australia|
|>2.4 - 5.92||Outer Regional Australia|
|>5.92 - 10.53||Remote Australia|
|>10.53||Very Remote Australia|
Figure 7 Remoteness Areas of Australia