Delimitation of urban centres
The principles and criteria used for the delimitation of urban centres in Australia at the 1966 Census were as follows:
A boundary was defined for all settlements with a population of 1,000 or more and these were named 'urban centres' except for the State capitals and Canberra which were named 'Metropolitan areas'. This boundary is one which, from census to census, as urbanisation proceeds, will be moved outwards to encompass any peripheral urban development.
For urban centres with a population of 30,000 and over and for a few smaller centres, the following criteria were adopted for delimiting the urban centres.
(a) The Metropolitan Area or urban centre was delimited by including all contiguous census collector's districts with a population density of 500 or more persons per square mile.
(b) Certain collector's districts, although not reaching the required population density, were also included by virtue of-
(i) land use (e.g. factory areas),
(ii) being surrounded by urban collector's districts,
(iii) forming a 'bridge' between two urban centres less than two miles apart so that they could be regarded as one single urban centre.
For urban centres of less than 30,000 population, local government area boundaries were adopted, unless they contained a large rural component or urban development was known to extend beyond the local government boundary. In these cases they were delimited by inspection of aerial photographs, by field inspection, or by consideration of any other information available, and the boundaries were set as closely as possible to the periphery of the built-up area without regard to local government boundaries.
In areas with large numbers of holiday homes, many of which are unoccupied at the mid-winter census date, dwelling rather than population criteria were used. These criteria were 250 dwellings (in lieu of the 1 ,000 population mentioned above) and 125 dwellings per square mile (in lieu of the 500 persons per square mile mentioned above). Around each metropolitan area and urban centre with a population of at least 75,000 and a regional population of at least 100,000, a further boundary was defined, designed to circumscribe an area which would contain the urban development of that centre for at least twenty years and which would generally be socially and economically oriented to the centre. These areas were designated 'Statistical Divisions' (for State capital cities) or 'Statistical Districts' (for Canberra, Newcastle, Wollongong and Geelong).
Because the new criteria for the delimitation of urban boundaries were adopted only shortly prior to the 1966 Census a few collector's districts containing urban growth were not split into their rural and (potentially) urban components, with the result that significant urban population remained included in large predominantly rural, collector's districts, which did not meet the density criterion. Such cases occurred mainly around the Sydney Metropolitan Area and Urban Toowoomba. The effect on the Sydney Metropolitan Area is small, probably not more than 5,000 urban population having been omitted. In Toowoomba the effect is proportionately much greater, the urban population probably being understated by up to 3,000 persons.