Dictionary, Census of Population, 2021
Figure 1.13
Example of data retrieval with user-defined boundaries

Figure 1.13 is a graphic representation of the information that is used to create user‑defined boundaries. Two user‑defined boundaries are shown and are represented by thick grey lines. Each of these boundaries includes partial and complete dissemination blocks.

The illustration is made up of a fictional grouping of streets and dissemination blocks. Dissemination blocks appear as polygons. Each block contains blockface representative points, which are represented by a small 'x' and are centred on the inside of each blockface. Each block also contains a dissemination block representative point located in the centre of the block, which is represented by a large, bolded plus sign (+).

In the bottom right quadrant, two dissemination blocks are crossed diagonally by a census subdivision (CSD) boundary. In order to respect the dissemination area geography, the CSD boundary splits each of the dissemination blocks that it crosses, thus creating two dissemination blocks out of one. Each one of these dissemination blocks contains a dissemination block representative point located in its centre.

Most dissemination blocks in this diagram also contain a series of small polygons that represent dwellings, shaded light grey or dark grey. Dwellings that are shaded light grey represent those that are excluded from the data retrieval since their blockface representative point falls outside the user‑defined area. Those that are shaded dark grey represent dwellings that are included in the data retrieval since their blockface representative point falls within the user‑defined area.

Below the figure is a legend which demonstrates the symbols used in the figure to represent blockface representative points, dissemination block representative points, the census subdivision boundary, dissemination block boundaries and a user‑defined boundary.

Source: Statistics Canada, 2021 Census of Population.