A Primer on Mapping the Census of Population: Who, What, Where?

(Disponible en français : Le point sur la cartographie du Recensement de la population : Qui, quoi, où?)

About the Census of Population

As a requirement of the Statistics Act, Statistics Canada conducts a census of population and agriculture every five years in the years that end in ‘1’ and ‘6’.  Data are collected using both short forms and long forms.

Short forms are sent to all private and collective dwellings to collect basic demographic information related to age, gender, household members and language. Long forms are sent to a sample of 25% of Canadian households asking questions related to daily activities, place of birth, labour and socio-cultural information. A significant change in the 2016 census was the collection of income data directly through income tax and benefit files.

It is important to note that data are aggregated, and individual responses are never published.

Census data are grouped into commonly recognized geographic regions such as provinces or Federal Electoral Districts. Data are also provided for smaller geographic regions to compare demographic data between populated places, urban and rural areas or between economic regions.

Geographic regions include Census Divisions (c.f. aggregated neighbouring municipalities), Census Subdivisions (municipalities such as individual cities, communities, parishes, villages etc.) and Dissemination Areas (areas that contain between 400-700 people counted at the previous census and composed of even smaller Dissemination Blocks).

Whereas all census of population data are published for larger geographic regions, only population and dwelling counts are published for Dissemination Blocks.

Interactive Map: Census geography – there lies the data
(Click in the map and on the arrows for more information)

Click here for map description

Most census regions are organized according to a hierarchy so that smaller regions can be nested within the boundaries of larger ones, allowing for consistency across scale. Dissemination Areas, for example, can be grouped together to form larger census subdivisions.

Why map census data?

Exploring census data at national, provincial or municipal levels can answer a number of questions regarding gender as well as ethnic, racial and socio-economic diversity. For instance, how many people speak a certain language, have migrated for employment, spent a large portion of income on housing, or live in households with few or many children?

It can be challenging, however, to communicate patterns for multiple geographic regions using a table. By mapping those data, one can contextualize it by location and visualize where and how values change at different levels of geography (or scale). Maps can even reveal spatial patterns that are otherwise undetected.

The percentage of the total population who are 65 years of age and older, for instance, will appear different when aggregated to the provincial level than at other, more detailed levels of geography.

Interactive map:  Percent of total population 65 and over at multiple levels of geography
(Click in the map and on the arrows for more information)

Click here for map description

Maps prepared by Library of Parliament, 2017, using data from Statistics Canada.  2016 Census of Canada.  Census Profile Tables. Using CHASS (accessed 26 October 2017) and Statistics Canada.  2016 Census – Boundary files. Ottawa: Statistics Canada, 2016. The following software was used: Esri, ArcGIS, version 10.3.1. Contains information licensed under Statistics Canada Open Licence Agreement.

Who uses the census?

Federal, provincial and municipal governments, businesses, universities, non-profit groups, media, think tanks and many other organizations use census data. The Government of Canada uses census data to produce population estimates that inform the allocation of funds to provincial and territorial governments related to health, social and equalization support.

Census data provide the building blocks to calculate demographic trends (age, education, employment, gender ratio, immigration, language, income and others), and estimate future demands on child tax benefits, pensions and other support programs.

While data patterns also allow observers to identify areas that need more detailed research, researchers exercise caution when making inferences about individuals from data grouped to an area.

Census data released to the public

Statistics Canada releases several types of data to the public:

Publicly available resources using population and dwelling counts include:

  • data tables and census profiles;
  • analytical products such as the ‘The Daily’ news and latest data releases, infographics, and videos;
  • reference dictionary and reference guides; and
  • geographic products such as spatial layers (boundary files) at various levels of geography; roads and rivers; thematic maps and guides.

Resources available by subscription or purchase include:

  • microdata files including data derived from surveys on health, the environment, travel etc.;
  • custom tabulations that link data between variables at the micro data level that do not appear in publicly available tables; and
  • custom maps.

Further reading:

Statistics Canada 2016 Census of Population:

Peters, A. and Macdonald, H. Unlocking the Census with GIS, ESRI Press; Redlands, California, 2004.

Author: Mélanie Zahab, Library of Parliament