Dictionary, Census of Population, 2021
Figure 1.1
Hierarchy of standard geographic areas for dissemination, 2021 Census

Figure 1.1 is a graphical representation of the hierarchical relationship between the standard geographical areas used for the dissemination of the 2021 Census of Canada. Each geographic area is represented in the hierarchy by a box, which is appropriately labelled with the area name, as well as its related acronym. Where applicable, the labels are formatted in two rows. The top row contains the acronym of the geographic area in bold font, and the second row contains the full name of the geographic area in regular font.

In total, there are 21 boxes stacked both horizontally and vertically. Boxes that represent administrative areas are shaded. Boxes that represent statistical areas are white.

The position of each geographic area in the hierarchy shows how it is related to other areas. Most geographic areas can be subdivided or aggregated to form other geographic areas. The lines joining the boxes in the hierarchy show that there are relationships between the geographic areas. When two boxes are not joined together by a line, then no relationship exists between those geographic areas. A solid line indicates a direct relationship between two areas. A dashed line indicates that two areas are connected using a point-in-polygon process. A dashed and dotted line (dash dot dash dot, etc.) indicates a best fit relationship between two geographic areas.

In general, there is a "one-to-many" relationship of geographic areas from the top to the bottom of the hierarchy diagram and a "many-to-one" relationship from the bottom to the top.

The box centered at the top of the hierarchy represents the highest level of geography, Canada, which is shaded blue to indicate that it is an administrative area. Directly below the Canada box is the geographical regions of Canada box, which is white. A solid line joins the Canada box to the geographical regions of Canada box (6).

Directly below the geographical regions of Canada box is the province or territory box (13). The province or territory box is connected to three other administrative areas on the left: federal electoral district (FED) (338), designated place (DPL) (1,685) and forward sortation area (1,669). It is also connected to two statistical areas on the left: census agricultural region (CAR) (72) and economic region (ER) (76).

Each of these boxes, with the exception of the forward sortation area, is connected to one box or another that rolls down to be ultimately linked to the lowest level of dissemination geography, the dissemination block (DB) (498,786) box, which is a statistical area. The forward sortation area is connected only to the postal code (OM: postal code is an official mark of the Canada Post Corporation) (880,864), an administrative area that has no further connections.

The DPL and the FED are connected directly to the DB, indicating that no other level of geography exists between them. The CAR and the ER are directly linked to the census division (CD) (293), which is connected first to the statistical area of the census consolidated subdivision (CCS) (1,757), which is further connected to the administrative area of the census subdivision (CSD) (5,161). The CSD is linked directly to the dissemination area (DA) (57,936), which is another statistical area. The DA is connected directly above to the census tract (CT) (6,247), which is another statistical area. The DA is also linked directly below to the DB.

The CD is also directly connected to the aggregate dissemination area (ADA) (5,433). The ADA is linked directly to the DA.

The Canada box is linked to one large statistical area box on the right, called the Statistical Area Classification (SAC). The SAC box is the most complicated box in the hierarchy since it encompasses four other statistical areas that make up all of Canada. These are categorized under two larger subcategories that indicate whether the area is part of a census metropolitan area or census agglomeration (CMA/CA) or is outside a CMA/CA (non-CMA/CA).

The CMA/CA category is divided into two boxes, the CMA (41) and the CA (111). The CA box is further subdivided into two other categories to indicate that CAs can be broken down into areas with census tracts (CTs) (9) and areas without CTs (102).

The non-CMA/CA category is also divided into two boxes, the census metropolitan influenced zone (MIZ) and the territories.

The SAC box is linked directly to the CSD. The CMA and the CA with CTs are linked directly to the CT.

Below the SAC is a box that is subdivided into four stacked boxes that list the categories of population centres (POPCTRs) in Canada. These include, from top to bottom, large urban population centre (34), medium population centre (58), small population centre (934) and rural area. The CMA/CA boxes are directly linked to all categories of POPCTRs, while the non-CMA/CA category is directly linked only to the small population centre and rural area boxes. This complete set is linked directly to the DB.

Below the DB, there are three other geographic areas that are not used for disseminating data. Instead, they are linked to the DB to provide reference or geocoding information of census data. The place name (PN) (40,526), which is a representative point, is linked to the DB by a dashed line, indicating linkage using a point-in-polygon process. The blockface (4,486,530) also a representative point, is linked directly to the DB. The CSD from the previous census (5,162) is linked to the DB by a dashed and dotted line, which indicates a best-fit linkage.

Source: Statistics Canada, 2021 Census of Population.