Geographic Attribute File, Reference Guide, Census year 2021

This reference guide is intended for users of the 2021 Geographic Attribute File. This guide provides an overview of the file, the general methodology used to create it, and important technical information.

What's new?

• The 2021 Geographic Attribute File is now only available in comma-separated value (.csv) format.
• The 2021 Geographic Attribute File now includes the Dissemination Geography Unique Identifier (DGUID) for all standard geographic areas.

1. About this guide

This reference guide is intended for users of the 2021 Geographic Attribute File. A record layout is provided in the Technical specifications section.

This data product is provided 'as-is,' and Statistics Canada makes no warranty, expressed or implied, including but not limited to, warranties of merchantability and fitness for a particular purpose. In no event will Statistics Canada be liable for any direct, special, indirect, consequential or other damages, however caused.

2. Overview

The 2021 Geographic Attribute File contains information at the dissemination block (DB) level, based on 2021 Census standard geographic areas. The data available include DB level population counts, dwelling counts and land area. In addition, the 2021 Geographic Attribute File contains higher level standard geographic codes, names and, where applicable, types and classes. Data for higher level standard geographic areas can be derived by aggregating DB level data. The dissemination area (DA) representative point coordinates are also included in the 2021 Geographic Attribute File.

3. About this product

Purpose of the product

The 2021 Geographic Attribute File is a dataset at the DB level that also contains the complete set of 2021 Census geographic areas. The purpose of the file is to provide users the ability to aggregate the DBs to all geographic levels, i.e., the complete geographic hierarchy.

Definitions and concepts

Geographic terms and concepts are briefly defined in the Dictionary, Census of Population, 2021.

Content

The 2021 Geographic Attribute File contains all the 2021 Census DBs and their selected attributes, such as standard geographic areas’ unique identifiers (UIDs), DGUIDs, population and dwelling counts, land area, 2021 Census incompletely enumerated Indian reserves and Indian settlements, and the corresponding DAs' representative point coordinates.

Hierarchy of standard geographic areas

The 2021 Geographic Attribute File is a DB level dataset which includes data for the following 2021 Census standard geographic areas:

• Provinces and territories (PRs)
• Census divisions (CDs)
• Federal electoral districts (2013 Representation Order) (FEDs)
• Census subdivisions (CSDs)
• Designated places (DPLs)
• Economic regions (ERs)
• Census consolidated subdivisions (CCSs)
• Census metropolitan areas (CMAs), census agglomerations (CAs), and census metropolitan influenced zones (MIZs)
• Census tracts (CTs)
• Population centres (POPCTRs) and rural areas (RAs)
• Dissemination areas (DAs)
• Dissemination blocks (DBs)
• Aggregate dissemination areas (ADAs)

The Figure 1.1, “Hierarchy of standard geographic areas for dissemination, 2021 Census,” illustrates the relationships between all standard geographic areas.

2021 Census population and private dwellings

The population and dwelling counts contained within the 2021 Geographic Attribute File are from the 2021 Census. The counts for a particular geographic area represent the number of people whose usual place of residence is in that area; regardless of where they happened to be on census day, May 11, 2021.

2021 Census land area

Land area is the area in square kilometres of the land-based portions of 2021 Census standard geographic areas. The land area data contained within the 2021 Geographic Attribute File may or may not be consistent with land area data provided by other sources. Land area is calculated using ArcGIS® software for the sole purpose of calculating population density.

Land area data for 2021 Census standard geographic areas reflect the boundaries in effect on January 1, 2021 (the geographic reference date for the 2021 Census of Canada).

2021 Census incompletely enumerated Indian reserves and Indian settlements

In 2021, some Indian reserves and Indian settlements were incompletely enumerated. For these reserves and settlements, dwelling enumeration was either not permitted or was interrupted before it could be completed.

The 2021 Census population and dwelling counts are not available for the incompletely enumerated Indian reserves and Indian settlements, and are not included in 2021 Census tabulations. Data for geographic areas containing one or more of these reserves and settlements are noted accordingly.

Positional data

The 2021 Geographic Attribute File contains the representative point coordinates for the DAs, weighted by population data. The representative point coordinates were projected in Lambert conformal conic projection (NAD83).

General methodology

The National Geographic Database (NGD) is a joint Statistics Canada-Elections Canada initiative to develop and maintain a spatial database which serves the needs of both organizations. The focus of the NGD is the continual improvement of quality and currency of spatial coverage using updates from provinces, territories and local sources. The native file used for the creation of the 2021 Geographic Attribute File resides on Statistics Canada's Spatial Data Infrastructure (SDI) which was derived directly from data stored in the NGD.

In creating the 2021 Geographic Attribute File, all DBs were extracted from the SDI along with data for the higher level standard geographic areas in which DBs are located. The corresponding geographies were then joined to the DBs, and completed with DBs population and dwelling counts.

Limitations

Not applicable

Comparison to other products or versions

The 2021 Geographic Attribute File contains UIDs, DGUIDs, names and, where applicable, types and classes applicable to the 2021 Census geographic areas.

The 2021 Geographic Attribute File includes all the DBs, while the “2021 Dissemination Block Cartographic Boundary File” does not include the DBs located entirely within coastal waters. See the 2021 Census Boundary Files, Reference Guide for more information.

Users should note that even when the boundaries of standard geographic areas did not change between the 2016 and 2021 censuses, the land areas may differ due to geometry shifts. The shifts are caused by the integration of CanVec hydrographic features, as well as improvements in the absolute positional accuracy of some of the roads.

Because of the missing counts for the incompletely enumerated Indian reserves and Indian settlements, users are cautioned that for the affected geographic areas, comparisons (e.g., percentage change) between 2016 and 2021 may not be precise.  The impact of the missing data can be significant for lower-level geographic areas (e.g., CSDs), where the incompletely enumerated Indian reserves and Indian settlements account for a higher proportion of the population. This is especially true for lower-level geographic areas where a particular Indian reserve or Indian settlement was incompletely enumerated for the 2021 Census but enumerated for the 2016 Census and vice versa.

Use with other products

The 2021 Census standard geographic areas in the 2021 Geographic Attribute File can be linked to other 2021 Census products using UIDs or DGUIDs.

The 2021 Census DB unique identifiers (DBUID) included in the 2021 Geographic Attribute File can be used with the 2021 Correspondence Files to identify corresponding 2016 Census DBs. The 2016 DBUIDs can then be linked to the 2016 Geographic Attribute File or 2016 Geosuite to retrieve the 2016 Census standard geographic areas and their attributes.

Reference date

Population and dwelling counts

The population and dwelling counts data contained within the 2021 Geographic Attribute File refer to the 2021 Census of Population which was conducted on May 11, 2021.

Standard geographic areas

The geographic reference date is a date determined by Statistics Canada to finalize the geographic framework for which 2021 Census statistical data are collected, tabulated and reported. The reference date for 2021 Census standard geographic areas is January 1, 2021.

4. Technical specifications

Record layout and data descriptions

The following table identifies and briefly describes the selected attributes comprising the content of the 2021 Geographic Attribute File.

Attribute domain values

Census division type (CDTYPE)

For information on census division types, refer to the “Census division type (CDTYPE), 2021 Census” table.

Census subdivision type (CSDTYPE)

Census subdivisions are classified according to designations adopted by provincial/territorial or federal authorities.

For information on census subdivision types, refer to the “Census subdivision type (CSDTYPE), 2021 Census” table.

Designated place type (DPLTYPE)

For information on designated place types, refer to the “Designated place type (DPLTYPE), 2021 Census” table.

Statistical Area Classification type (SACTYPE)

The Statistical Area Classification type is a one-digit code that identifies whether a CSD is a component of a CMA, a CA, a MIZ or in the territories.

For information on Statistical Area Classification types, refer to the “Statistical Area Classification type (SACTYPE), 2021 Census” table.

Statistical Area Classification code (SACCODE)

The Statistical Area Classification code is a three-digit code that groups CSDs according to whether they are a component of a CMA, CA or MIZ. MIZ categories denote the degree of influence that the CMAs and/or CAs have on these zones.

For information on Statistical Area Classification codes, refer to the “Statistical Area Classification code (SACCODE), 2021 Census” table.

Census metropolitan area and census agglomeration type (CMATYPE)

For information on census metropolitan area and census agglomeration types, refer to the “Census metropolitan area and census agglomeration type (CMATYPE), 2021 Census” table.

Population centre and rural area type (POPCTRRATYPE)

For information on population centre and rural area types, refer to the “Population centre and rural area type (POPCTRRATYPE), 2021 Census” table.

Population centre and rural area size classes (POPCTRRACLASS)

For information on population centre and rural area size classes, refer to the “Population centre and rural area size classes (POPCTRRACLASS), 2021 Census” table.

File specifications

The 2021 Geographic Attribute File size is approximately 300 megabytes in comma separated value format (.csv).

Software formats

This reference guide does not provide details on specific software packages that are available for use in comma separated value format (.csv). Users are advised to contact the appropriate software vendor for information. Users should be aware that the comma separated value (.csv) files contain leading zeroes which not all spreadsheet software recognize. If the software does not load the leading zeroes, users should import the files as text/csv instead, in order to view the files properly.

File extension and accented character information

The .csv file is compressed into a WinZip® file (file extension .zip).

Geographic representation

Not applicable

File naming convention

The 2021 Geographic Attribute File follows a standard naming convention. The file name includes: Census year, catalogue number and file format.

The 2021 Geographic Attribute File is named as follows: 2021_92-151_X.csv

5. Data quality

Data quality elements provide information on the fitness-for-use of a dataset by describing why, when, how the data are created, and how accurate the data are. The quality elements include an overview reporting on the lineage, positional accuracy, attribute accuracy, logical consistency and completeness. This information is provided to users for all geographic data products disseminated for the census.

Lineage

Lineage describes the history of the data, including descriptions of the source material from which the data were derived and the methods of derivation. It also contains the dates of the source material and all transformations involved in producing the file.

All data in the 2021 Geographic Attribute File were originally extracted from Statistics Canada's SDI.

Positional accuracy

Positional accuracy refers to the absolute and relative accuracy of the positions of geographic features. Absolute accuracy is the closeness of the coordinate values in a dataset to values accepted as or being true. Relative accuracy is the closeness of the relative positions of features to their respective relative positions accepted as or being true. Descriptions of positional accuracy include the quality of the final file or product after all transformations.

The only positional data contained within the 2021 Geographic Attribute File are the representative point coordinates of DAs. Within Statistics Canada's SDI representative point coordinates were generated using ArcGIS® software in conjunction with DA boundaries. The representative point coordinates were initially calculated based on the Lambert conformal conic projection; they were then transformed to latitude and longitude coordinates.

Attribute accuracy

Attribute accuracy refers to the accuracy of the quantitative and qualitative information attached to each feature (such as population counts for DBs, census subdivision unique identifiers (CSDUID), names and types).

The UIDs, DGUIDs, names, types and classes contained within the 2021 Geographic Attribute File, along with the relationships between all standard geographic areas, were verified against Statistics Canada's SDI and found to accurately reflect them.

Blank fields are displayed within the 2021 Geographic Attribute File where population and dwelling counts have been suppressed due to incompletely enumerated Indian reserves and Indian settlements. Population counts for Indian reserve refusal CSDs are not included in any census counts, therefore the blank population counts at the DB levels are consistent with the 2021 Census statistical data.

Logical consistency

Logical consistency describes the fidelity of relationships encoded in the data structure of the digital spatial data.

Consistency between data at various geographic levels was verified. Verification procedures ensured that counts at lower geographic levels sum to higher geographic levels.

Consistency with other products

The population and dwelling count data in the 2021 Geographic Attribute File are consistent with those disseminated in other 2021 Census products. The UIDs and DGUIDs used in the 2021 Geographic Attribute File are the same as those used in other geography products and represent the same geographic areas.

Completeness

Completeness refers to the degree to which geographic features, their attributes and their relationships are included or omitted in a dataset. It also includes information on selection criteria, definitions used and other relevant mapping rules.

The 2021 Geographic Attribute File contains one record for each of the 498,786 DBs. It also contains the appropriate geographic areas for each standard geographic level. The data in Table 1.1, “Geographic areas by province and territory, 2021 Census,” were verified within the 2021 Geographic Attribute File.