Statistics Canada uses a very accurate and detailed geographic structure that makes it possible to obtain information for many different geographical units, known as geographic areas. Data from the 1991 Census are available for numerous standard geographic areas, as well as for non-standard or user-defined areas. Standard areas are of two types:
(a) Legislative/administrative areas are defined, with a few exceptions, by Canadian federal and provincial statutes. These include:
(b) Statistical areas are defined by Statistics Canada as part of the spatial frame used to collect and disseminate census data. These include:
The main difference between the two is that the administrative regions are areas defined by other authorities and are adopted for purposes of the census whereas the statistical areas are defined by Statistics Canada for the purposes of producing census data and of complementing the structure of administrative regions. The main links between the two types of geographic areas are examined in Subsection 1.3 .
The enumeration area is the smallest unit and the building block underlying all other standard geographic areas. For example, the 45,995 EAs can be aggregated into 295 federal electoral districts or into 6,006 census subdivisions.
As well, two new types of geographic regions have been added to the hierarchy of standard administrative areas: the subprovincial region and the agricultural region.
1.3 Overview of the Standard Geographic Areas
The following standard geographic areas are used in the dissemination of census data:
|Geographic area||Total number|
|Enumeration areas (EAs)||45,995|
|Census tracts (CTs)||4,068|
|Provincial census tracts (PCTs)||1,815|
|Urban areas/rural areas||893|
|Primary census metropolitan areas (PCMAs)||12|
|Primary census agglomerations (PCAs)||21|
|Census metropolitan areas (CMAs)||25|
|and census agglomerations (CAs)||115|
|Federal electoral districts (FEDs)||295|
|Census subdivisions (CSDs)||6,006|
|Census consolidated subdivisions (CCSs)||2,630|
|Census divisions (CDs)||290|
|Subprovincial regions (SPRs)||68|
Definitions, historical boundary changes and descriptions of
available maps are covered more thoroughly in the other
census reference products, including the 1991 Census
Dictionary (Statistics Canada, Catalogue No. 92-301 E or D),
the 1991 Census Catalogue (Statistics Canada, Catalogue No.
92-302 E) and the 1991 Census Geography: A Historical Comparison
(Catalogue No. 93-311 E).
1.3.1 Enumeration area (EA)
An enumeration area is the area canvassed by one census
representative. It is the basic building block of all standard
geographic areas. EAs are defined by the number of
households they contain and by physical boundaries
such as bodies of water and streets. An EA never cuts
across any boundary recognized by the census.
The enumeration area is normally the smallest geographical
unit for which census data are available. Therefore, it is
defined in accordance with the following criteria:
(a) Dwellings: the number of dwellings in an EA may vary from 375 (maximum) in large urban areas to 125 (minimum) in rural areas.The EAs are primarily census collection units; they are not designed as dissemination areas. For reasons of confidentiality, only some information is available.
(b) Limits: since the EA is the basic unit for all geographic areas, it must never overlap an area recognized by the census (federal electoral districts, census divisions, census subdivisions, census tracts, etc.) Moreover, the borders are defined in such a way that the Census Representative can locate them without difficulty (for example, using streets, roads, railways and rivers).
All CMAs and CAs containing a CSD with a population of 50,000 or more at the previous census are eligible for a census tract program. For example, the central area of the Sherbrooke CMA is divided into CTs. Once an urban centre is added to the program, it is retained even if its population subsequently declines.
An example of the kind of social research done using census tract boundaries is "Changes in Mortality by Income in Urban Canada from 1971 to 1986". The findings of this study were a joint effort undertaken by the Policy, Planning and Information Branch, Health and Welfare Canada, and the Canadian Centre for Health Information, Statistics Canada. In this study, postal codes were matched to census data for particular census tracts by using the Postal Code Conversion File (PCCF). The purpose of such a study is to enable communities to analyse community health, prepare plans for the future and monitor and evaluate local health programs.
(a) urbanized core: a large urban area around which a CMA or CA is delineated;
(b) urban fringe: an urban area within a CMA or CA, but outside of the urbanized core;
(c) rural fringe: all territory within a CMA or CA lying outside of urban areas.
Every CMA, CA, PCMA and PCA has an urbanized core, but may or may not have urban or rural fringe areas. The total urbanized core of a consolidated CMA or CA is the sum of the constituent cores. Similarly, the totals for urban and rural fringes of a consolidated CMA or CA are the sums of the constituent fringes.
This consolidated CMA is divided into a primary census metropolitan area (PCMA) and one or more primary census agglomerations (PCAs). Thus, a PCMA or a PCA is a labour market subregion within the larger consolidated CMA or CA. All PCMAs or PCAs, like regular CMAs contain one or more census subdivisions.
A CA is the main labour market area of an urbanized core with a population of at least 10,000 based on the previous census. The 1991 Census recognizes 25 CMAs and 115 CAs.
Once a CA attains an urbanized core population of 100,000, it becomes a CMA and continues to be one even if its population subsequently declines below 100,000. However, if the population of a CA in an urbanized core drops below 10,000, the CA is removed from the CA program.
The 1991 CMAs and CAs were delineated using data derived from the place of work and place of residence questions in the 1981 Census (see Section 5 of this chapter for a description of these two questions). For a census subdivision (CSD) to be included in a CMA, at least one of the following criteria must be satisfied:
the CSD falls completely or partly inside the urbanized core;
at least 50% of the employed labour force living in the CSD works in the urbanized core;
at least 25% of the employed labour force working in the CSD lives in the urbanized core;
if a CSD meets the criteria for inclusion, but is not contiguous to a CMA, the place of work commuting flow data are aggregated for all CSDs within the census consolidated subdivision (CCS) - inclusion or exclusion of the entire CCS within a CMA is then determined;
if the commuting flow is less than 100 persons, CSDs are excluded from the CMA, even if the second or third criteria apply;
even if the second, third, fourth or fifth criteria apply, CSDs may be included or excluded to maintain the contiguity of the CMA.
Adjacent CMAs and CAs which are socially and economically integrated are grouped to form a single consolidated CMA or CA. Regular CMAs and CAs, on the other hand, are independent. For such areas to be eligible for consolidation, the total commuting interchange between the particular CMAs and CAs must be equal to at least 35% of the labour force living in the smaller CMA or CA. If consolidation takes place, the original CMAs or CAs become subregions (called primary CMAs or CAs) within the consolidated CMA or CA.
The implications for residents occupying areas subject to consolidation could include, for instance, additional taxes to support metropolitan services. Increased taxes in support of city public transportation systems is an example of the possible effects of consolidation. On the other hand, the residents of such areas could be eligible to apply for special programs and benefits.
FEDs are defined according to the following criteria:
. the legal limits and descriptions are the responsibility of the Chief Electoral Officer and are published in the Canada Gazette;
. FED limits are usually revised every I 0 years after the results of the decennial census
Census consolidated subdivisions are delineated according to these rules:
*all CSDs smaller than 25 square kilometres are grouped with a larger CSD;
*a CSD larger than 25 square kilometres forms a CCS of its own unless it is surrounded on more than half its perimeter by another CSD; then it is included as part of the CCS formed by the other CSD;
*a CSD with a population greater than 100,000 persons forms a CCS on its own if it is surrounded by rural CSDs;
*the CCS name usually coincides with its largest CSD components in terms of land area.
There has been a complete restructuring of census divisions in Quebec between 1986 and 1991. CDs in Quebec will now respect the same legal limits as the municipalites regionales de comtes (MRCs) or their equivalents (e.g. "communautes urbaines" and territoires conventionnes"). The implementation of MRCs (or their equivalents) has led to an increase in the number of CDs in Quebec, from 76 in 1986 to 99 in 1991.
In Ontario, the CDs correspond to the counties, districts, district municipalities, metropolitan municipalities, regional municipalities and united counties.
Before we had postal codes, counties were used for identification purposes when sending by mail. They have been retained for the census so that data obtained over the years may be compared.