Dictionary, Census of Population, 2021
Figure 1.16
Manual adjustment rule

Figure 1.16 is a graphical representation of the manual adjustment rule (rule 6^{Note 1}) for delineating a census metropolitan area (CMA). A fictional grouping of 12 census subdivisions (CSDs), shown as polygons labelled 'A' through 'L,' represent the group of CSDs that could form a CMA.

All of CSD A and a small portion of the adjacent CSDs B and J are shaded to represent a population centre. This population centre also makes up the core of the CMA. Census subdivision D has a small, shaded polygon within it that identifies a population centre that is not part of the core and is therefore referred to as fringe.

Given that CMAs are an aggregation of CSDs, CSDs A and B are fully included in the CMA because of the delineation core rule, whereas CSD J is part of the CMA because of the manual adjustment rule, since less than 50% of its population is located in the core.

Census subdivision K is a small CSD located in the larger CSD B. Excluding CSD K would create a core hole, so CSD K is part of the CMA under the manual adjustment rule to maintain spatial contiguity.

CSD L, is made up of two separate parts, one of which is adjacent to CSDs C and J meaning that it is completely surrounded by other CSDs already included in the CMA. CSD L is therefore included in the CMA under the manual adjustment rule to maintain spatial contiguity.

A thick black line outlines the perimeter of CSDs A, B, C, D, E, F, G, H, I, J, K and L to identify the new boundary of the CMA.

Two legends appear below the figure. The legend on the left identifies the symbols used in the figure to represent the boundaries of the CMA, CSD, population centre, core and fringe. The legend on the right distinguishes which CSDs are included in the CMA by which rule. For this figure, CSDs A and B are included under rule 1 (delineation core rule), CSD C is included under rule 2 (forward commuting flow rule) and CSD D is included under rule 3 (reverse commuting flow rule). CSDs E, F, G and H are included under rule 4 (spatial contiguity rule), CSD I is included under rule 5 (historical comparability rule), and CSDs J, K and L are included under rule 6 (manual adjustment rule).

Source: Statistics Canada, 2021 Census of Population.