5. Data quality

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Data quality elements provide information on the fitness-for-use of data by describing why, when and how the data are created, and how accurate the data are. The quality elements include information on lineage, positional accuracy, attribute accuracy, logical consistency, consistency with other products and completeness. This information is provided to users for all geography 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. It also contains the dates of the source material, and all transformations involved in producing the final map products.

The 2011 Census statistical data are disseminated for a variety of 2011 Census standard geographic areas ranging from the national level down to the dissemination block. Appendix B shows the hierarchy of standard geographic units and indicates whether 2011 Census standard geographic areas are administrative or statistical. Administrative areas include census subdivisions, census divisions, and provinces and territories. Statistics Canada established the Standard Geographical Classification (SGC) to organize these three types of 2011 Census standard geographic areas using a hierarchy of standard geographic codes. Reference maps depict the boundaries of these 2011 Census standard geographic areas and help users put 2011 Census statistical data in a spatial context.

Geographic names refer to the names given to standard geographic areas. Geographic names, however, are not given to all standard geographic areas. Named standard geographic areas include provinces and territories, economic regions, census divisions, census consolidated subdivisions, census subdivisions, census metropolitan areas, census agglomerations, designated places, populations centres and federal electoral districts. Although census tracts do not have alphabetic names, they do have numeric names consisting of seven characters, which include leading zeros, a decimal point and trailing zeros.

The maps contain both English and French province and territory names on the maps (where applicable). The sources used for the names of the provinces and territories are the statutes of the respective provinces and territories.

The source of the geographic names of federal electoral districts is the 2003 Representation Order, Elections Canada.

For those census divisions and census subdivisions that respect the administrative fabric within the provinces and territories, the sources of the names and types are the provincial and territorial governments. Statistics Canada receives input from the provincial and territorial governments concerning all boundary, name and type changes to their respective municipal structures. The census reflects the administrative structure within provinces and territories that was in effect on the geographic reference date of the 2011 Census, January 1, 2011.

Census metropolitan area and census agglomeration names are usually based on that of the largest population centre(s) within the census metropolitan area or census agglomeration.

Information on the delineation criteria for 2011 Census standard geographic areas as well as the sources of geographic names is provided in the 2011 Census Dictionary (Catalogue no. 98-301-X) and the 2011 Census Illustrated Glossary (Catalogue no. 92-195-X).

The map projection for all maps is Lambert Conformal Conic utilizing specific provincial parameters. Census metropolitan areas and census agglomerations which cross provincial boundaries use the projection parameters associated with the provincial part which is larger in terms of land area.

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.

All boundary layers used on the maps are stored in Statistics Canada's Spatial Data Infrastructure. The Spatial Data Infrastructure is not Global Positioning Systems (GPS)-compliant. However, every possible attempt is made to ensure that the 2011 Census standard geographic area boundaries maintained in the Spatial Data Infrastructure respect the limits of the administrative entities that they represent (e.g., census division and census subdivision) or on which they are based (e.g., census metropolitan area or census agglomeration). The positional accuracy of these limits is dependent upon source materials used by Statistics Canada to identify the location of limits. In addition, due to the importance placed on relative positional accuracy, the positional accuracy of other geographic data (e.g., road network data and hydrographic data) that are stored within the Spatial Data Infrastructure is considered when positioning the limits of the 2011 Census standard geographic areas.

The national map showing the location of the census metropolitan areas and census agglomerations was produced using point symbols that were positioned to portray the areas' proximity to major hydrographic features and the Trans-Canada Highway.

Attribute accuracy

Attribute accuracy refers to the accuracy of the quantitative and qualitative information attached to each feature (e.g., census subdivision name, unique identifier).

As noted under Lineage, the attributes (names, types and unique identifiers) for all 2011 Census standard geographic areas are sourced from Statistics Canada's Spatial Data Infrastructure. The names and types of administrative 2011 Census standard geographic areas have been updated for the 2011 Census using source materials from provincial and territorial authorities.

The 2011 standard geographic areas, road and hydrographic attributes on the reference maps were verified against the data in the Spatial Data Infrastructure and found to be accurate.

Logical consistency

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

On each reference map, all 2011 Census standard geographic areas have been verified to have a unique identifier that is valid for the 2011 Census.

Consistency with other products

The information displayed on 2011 Census reference maps such as boundaries, names and unique identifiers of 2011 Census standard geographic areas, roads, rivers and lakes are consistent with those disseminated within other 2011 Census products except in the three dissemination area (DA) map series, where the DAUID is shown as a six-digit UID, not eight digits, due to space limitations on the map. The first two digits of the DAUID, representing the province/territory code, do not appear. The remaining six digits represent the census division (CD) and DA.

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 criteria. There is a national coverage of census divisions, census subdivisions, dissemination areas, dissemination blocks, economic regions and federal electoral district. Throughout all of the 2011 Census map series, the 2011 Census geographic areas are displayed in some manner.

The base map features selected for display on the national maps include only selected rivers and lakes and the Trans-Canada Highway.

The Census Tract Reference Maps, by Census Metropolitan Areas and Census Agglomerations series contains all 33 census metropolitan areas and 15 census agglomerations that are part of the 2011 census tract program. For each census metropolitan area and census agglomeration, all census tracts are named.

New for 2011 is that census boundaries of designated places (DPLs) may cross census subdivision (CSD) boundaries. For all maps showing DPLs the maps display only the portion of the DPLs that is within the target area of the map. On these maps, DPL names are suffixed with (part/partie) to identify DPLs that have additional parts whose extent is outside the target area of the map and is not displayed.

Table 5.1
2011 Census designated places that cross census subdivision boundaries
Designated place unique identifier Designated place name Designated place type Province name
100285 Sheshatshiu DPL Newfoundland and Labrador
130097 Upper Miramichi LSD New Brunswick
460103 Grand Marais/Grand Beach UUC Manitoba
460105 Birch River LUD Manitoba
480082 Flyingshot Lake UNP Alberta
590038 Genelle UNP British Columbia
590068 Saltair UNP British Columbia
590177 Hyde Creek UNP British Columbia
590266 Barriere UNP British Columbia
590341 Port Renfrew UNP British Columbia

There is one area where a designated place and a population centre overlap. In the census agglomeration of Duncan, B.C., the designated place of Cowichan 1 (59 0321) has been given precedence over the population centre of Duncan (59 0243) for mapping purposes.

Population centre information (i.e., shading) is displayed for the target area only.

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