Publications
Population Ecumene Census Division Cartographic Boundary File, Reference Guide
3. About this product
Purpose of the product
Definitions and concepts
Content
General methodology
Limitations
Comparisons to other products/versions
Using with other products
Reference date
Purpose of the product
The population ecumene is designed to assist users in thematically mapping data. By effectively masking non-ecumene areas of Canada, it enables users to display data in areas where population is concentrated.
An ecumene mask is useful for dot and choropleth thematic mapping. In dot map applications, if an ecumene is not applied, the dots may be spread over the spatial extent of a geographic area. This approach defeats the main attributes of dot mapping (i.e., showing correct location, extent and density of various characteristics).
In choropleth map applications, one of the inherent limitations is that the statistical distribution is assumed to be homogeneous or uniformly spread over each geographic area, and is consequently represented by a single tone or colour covering the entire area. Using an ecumene limits the display to only those areas where population is found and results in a more accurate representation of the spatial distribution of data.
Definitions and concepts
Geographic terms and concepts are briefly defined in the glossary (Appendix A). More details can be found in the 2011 Census Dictionary (Catalogue no. 98-301-X) and the 2011 Illustrated Glossary (Catalogue no. 92-195-X).
Content
The 2011 Census Population Ecumene Census Division Cartographic Boundary Files product consists of four spatial files:
1. Ecumene mask file
The ecumene mask consists of polygons flagged with a value: 1, being in the ecumene; 0, outside the ecumene. There is at least one ecumene polygon in every census division in Canada.
2. Census division boundary file
The census division boundary file contains census division boundaries. Related attribute information is available for each census division polygon, including a unique identifier, name and type.
3. Province and territory boundary file
The province and territory boundary file contains the boundaries of the provinces and territories. Related attribute information is available for each province and territory polygon, including a unique identifier, English name, French name, English abbreviation and French abbreviation.
4. Hydrographic reference file
The hydrographic reference file contains a selection of lakes. Each hydrographic feature contains a unique identifier.
All spatial files are available in English and in French, in three formats: ArcGIS® (.shp), Geography Markup Language (.gml) and MapInfo® (.tab).
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 files used for the creation of the 2011 Census population ecumene spatial files reside on Statistics Canada's Spatial Data Infrastructure which was derived directly from data stored on the NGD.
The reference files that make up the population ecumene were created using the following processes:
Creation of the 2011 Census population ecumene census division spatial files
A) Ecumene mask file
The ecumene mask file was created by using the land area and the current census population count to calculate the population density of each dissemination block. Every dissemination block was then classified as either being an ecumene block (meeting the population density criteria of 0.4 or more persons per square kilometre) or being a non-ecumene block (those with a population density below 0.4 persons per square kilometre). The resulting ecumene outline was smoothed and buffered to facilitate small scale mapping.
B) Creation of the generalized cartographic boundary files
To create the generalized cartographic boundary files, a subset of the full hydrography, the coastal layer, was created.
Using the source hydrography file, all generalized coastal water features were extracted. Hydrography features were then dissolved to create one coastal file used in the creation of the generalized province and territory and census division boundary files included in this product.
The coastal hydrographic features were then used to erase the portions of census divisions that are covered by coastal waters. Subsequently, the province and territory file was derived from the census division file.
C) Creation of the hydrographic reference file
The hydrographic reference file contains a selection of water features from the National Geographic Database's hydrographic reference layer. These reference data were sourced from the National Topographic Data Base (1:50,000 and 1:250,000) and the Digital Chart of the World (1:1,000,000). In British Columbia, information was supplemented with data from the National Hydro Network. All small islands were transformed into water polygons.
Final data processing consisted of the conversion from the File Geo Database format, using FME® (Safe Software), into the following Geographic Information System (GIS) file formats: ArcGIS® (.shp), Geography Markup Language (.gml) and MapInfo® (.tab).
Limitations
The positional accuracy of these files does not support cadastral, surveying, digitizing or engineering applications.
The input data used to create the files were obtained from several sources having a wide range of scales. Maps created from the 2011 Census Population Ecumene Census Division Cartographic Boundary Files should not be used to determine the precise location of boundaries.
Comparison to other products/versions
The 2011 Census population ecumene mask file is generalized to render it suitable for cartographic display at a small scale (i.e., 1:20,000,000 to 1:25,000,000). Due to this generalization, the position of the shoreline is not necessarily consistent with the suite of census cartographic boundary files.
The 2011 Census Population Ecumene Census Division Cartographic Boundary Files are similar but not necessarily consistent with ecumene boundary files released prior to the 2011 Census.
Using with other products
The 2011 Census Population Ecumene Census Division Cartographic Boundary Files can be linked to other 2011 Census statistical data products using the unique identifier (UID) for each geographic area.
The 2011 Census Population Ecumene Census Division Cartographic files are generalized to render them suitable for cartographic display at a small scale. Due to this generalization, the position of the shorelines are not necessarily consistent with the suite of 2011 Census Cartographic Boundary Files or 2011 Census Road Network File.
When considering using the 2011 Census Population Ecumene Census Division Cartographic Boundary Files, users should be aware of the compatibility of these files with those that are available from other sources. They may not be consistent with Statistics Canada files.
Reference date
The geographic reference date is a date determined by Statistics Canada to finalize the geographic framework for which 2011 Census statistical data are collected, tabulated and reported. The reference date for 2011 Census standard geographic areas is January 1, 2011. More specifically, the census reports data according to the geographic areas (e.g., municipalities and equivalents referred to as census subdivisions) that are in effect on January 1, 2011, provided that Statistics Canada receives the information on the changes by March 1, 2011 (see 2011 Census Dictionary – Geographic reference date for more details).
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