Queriable Layers
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What are Queriable Layers
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How are Queriable Layers Created?
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Strengths and Limitations
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Queriable Layers Available
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What are Queriable Layers?
What are Queriable Layers?: Queriable layers are a set of data points on the map that can be extracted using either the Query or Proximity tools. Once the points have been highlighted using these tools, they can be used as basis for generating reports and/or exporting data. Using the Query tool, data can be extracted for a custom defined areas such as an area around an street address or a facility (circular buffer or an area drawn on the map by the end-user). The Proximity tool on the other hand, can be used to quickly extract data using existing administrative boundaries
Examples: For example, one could load the 2016 population layer into the Query tool to generate a report on the population or income characteristics of people living within 1 km of a community center.
Similarly, one could load the school layer into the Query or Proximity tools to identify the all of the elementary schools within a particular geographic area, generate a summary report of the number of students by grade, and then export an Excel spreadsheet that would include school contact information and the number of students by grade.
How are Queriable Layers Accessed and Used?: Some queriable layers appear both as a visible layer on the map (i.e. schools), while other queriable layers such as the 2016 Census Population layer are only accessible through the Query or Proximity Tools and are not visible as map layers.
Worked Examples: For worked examples of how to manipulate Queriable layers using either the Query or Proximity Tools, navigate to the following user support resources:
Examples: For example, one could load the 2016 population layer into the Query tool to generate a report on the population or income characteristics of people living within 1 km of a community center.
Similarly, one could load the school layer into the Query or Proximity tools to identify the all of the elementary schools within a particular geographic area, generate a summary report of the number of students by grade, and then export an Excel spreadsheet that would include school contact information and the number of students by grade.
How are Queriable Layers Accessed and Used?: Some queriable layers appear both as a visible layer on the map (i.e. schools), while other queriable layers such as the 2016 Census Population layer are only accessible through the Query or Proximity Tools and are not visible as map layers.
Worked Examples: For worked examples of how to manipulate Queriable layers using either the Query or Proximity Tools, navigate to the following user support resources:
- Video Tutorials:
- #9: Using the Query Tool to Generate Population and Income Reports
- #10: Using the Query Tool to Produce a Custom School Report
- #11: Using the more advanced Proximity Tool to flexibly Generate Custom Analyses and Reports
- Case Base Training Manual:
- Topic #10: How can I Identify the characteristics of people living within a custom area such as within 1 km of a school, community center or a specific address
- Topic #11: How can I extract a list of schools and a summary report of student counts by grade within a pre-defined geographic area such as a school division, electoral ward, or neighborhood
- Topic #13: How can I extract features within a custom area defined using the draw/trace tool?
- Topic #14: How can I identify the characteristics of people living within a predefined geographic areas such as electoral ward or neighborhood?
How are Queriable Layers Created?
Queriable layers are a dense matrix of data points on the map that can be extracted or lassoed using either the Query or Proximity tools. For schools, these points are the school locations themselves.
For census based queriable layers such as population or income however, the data points are the centroids (center point) of dissemination blocks (DBs) that are attributed with census data. Dissemination blocks are the smallest geographic areas used routinely by Statistics Canada to disseminate total population counts. DBs roll-up into larger dissemination areas (DAs) which are in turn the smallest geographic areas for which Statistics Canada distributes detailed Census data. There are around 4 to 10 DBs in each DA.
In Winnipeg and Manitoba there are approximately 5500 and 21,000 DBs respectively.
The queriable layer for the 2016 Census Income, for example, is constructed by allocating to each dissemination block (DB) the population weighted estimated income counts from the dissemination area (DA) that the DB falls into. For example, if a DB contains 20% of the total population of the DA it falls into, that DB will be allocated 20% of the income count data.
Note: To avoid allocating data to non-populated areas, dissemination block centroids were shifted where necessary using data from the 2015 Postal Code Conversion file in order to determine where in a DB the majority of the population is most likely to be located.
For census based queriable layers such as population or income however, the data points are the centroids (center point) of dissemination blocks (DBs) that are attributed with census data. Dissemination blocks are the smallest geographic areas used routinely by Statistics Canada to disseminate total population counts. DBs roll-up into larger dissemination areas (DAs) which are in turn the smallest geographic areas for which Statistics Canada distributes detailed Census data. There are around 4 to 10 DBs in each DA.
In Winnipeg and Manitoba there are approximately 5500 and 21,000 DBs respectively.
The queriable layer for the 2016 Census Income, for example, is constructed by allocating to each dissemination block (DB) the population weighted estimated income counts from the dissemination area (DA) that the DB falls into. For example, if a DB contains 20% of the total population of the DA it falls into, that DB will be allocated 20% of the income count data.
Note: To avoid allocating data to non-populated areas, dissemination block centroids were shifted where necessary using data from the 2015 Postal Code Conversion file in order to determine where in a DB the majority of the population is most likely to be located.
Strengths and Limitations of Queriable Layers
Strength: The use of Queriable Layers is a powerful approach to since it allows data to be loaded once into the map, and then extracted in many different ways by end-users depending upon their specific needs. By loading data as a dense matrix of points, data can be extracted flexibly using either existing administrative boundaries (Proximity tool), or by custom areas defined by the end-user (Query tool).
Limitation: There are limitations to the use of queriable layers that should be kept in mind. These limitations stem from the fact that dissemination block and dissemination area boundaries often do not line up cleanly with the boundaries of our administrative boundaries of interest (i.e. neighborhoods, electoral wards etc.). As a result, output reports generated using queriable census layers may provide summary counts and rates that are slightly in error.
Note: The difference between actual values and those generated using queriable census layers diminishes as the size of the extraction area increases (at the level of the City Electoral Ward or Community Area the errors are neglible). These errors may also be exacerbated for small geographic areas because of the random rounding introduced by Statistics Canada to protect confidentiality and the fact that Census population counts are frequently under-counts.
Limitation: There are limitations to the use of queriable layers that should be kept in mind. These limitations stem from the fact that dissemination block and dissemination area boundaries often do not line up cleanly with the boundaries of our administrative boundaries of interest (i.e. neighborhoods, electoral wards etc.). As a result, output reports generated using queriable census layers may provide summary counts and rates that are slightly in error.
Note: The difference between actual values and those generated using queriable census layers diminishes as the size of the extraction area increases (at the level of the City Electoral Ward or Community Area the errors are neglible). These errors may also be exacerbated for small geographic areas because of the random rounding introduced by Statistics Canada to protect confidentiality and the fact that Census population counts are frequently under-counts.
Queriable Layers Available
The following queriable layers are available:
- 2016 Census Population:
- Available for both the Winnipeg and Manitoba Community maps
- Winnipeg Map: Census Pop 2016
- Manitoba Map: Mb Census Pop 2016
- Can be used in both the Query and Proximity Tools
- Generates a summary report of the 2016 Census Population by total population, age and gender specific population counts (5 year age groups), and population counts by income quintile.
- The 2016 Census tends to under-count the actual population by about 3% overall. This appears to be a greater problem in low-income populations in the Winnipeg Health Region, where the under-count may be as great as 10%.
- Available for both the Winnipeg and Manitoba Community maps
- 2016 Census Income:
- Available for both the Winnipeg and Community Maps
- Winnipeg Map: Mb Census Income 2016
- Manitoba Map: Mb Census Income 2016
- Can be used in both the Query and Proximity Tools
- Generates a summary report of Before Tax Median Household Income levels, including the overall median household income for the extracted area as well the number of households by median income category ranges. The report also provides an estimate of the number of individuals living in low income households by broad age group.
- Note: The income data provided by the 2016 Census is based on 2015 Tax-filer data, and therefore represents 2015 income levels.
- See the Median Household Income 2015 layer in the Data Dictionary (Pop. Characteristics tab) for more information
- Available for both the Winnipeg and Community Maps
- 2016 Census Ethnicity and Immigration (North American Aboriginal Origins, Recent Immigrants, Visible Minorities)
- Available for both the Winnipeg and Manitoba Community Maps:
- Winnipeg/Manitoba Maps: Census Ethnocultural 2016
- Can be used in both the Query and Proximity tools
- Creates a summary report:
- The count and % of individuals having North American Aboriginal origins (subset by First Nation, Metis and Inuit),
- The count and % of individuals who are immigrants (immigrated at anytime) and recent immigrants (immigrated between 2011 and 2016)
- The count and % of individuals who are visible minorities (non-white, non-Aboriginal). This includes data for 13 derived groups: South Asian, Black, Chinese, Filipino, Arab, Latin American, South East Asian, Korean, West Asian and Japanese
- Limitation: The Immigrant data for significant portions of northern Manitoba has been suppressed. See the data dictionary for more details (% Recent Immigrants 2016 layer)
- Available for both the Winnipeg and Manitoba Community Maps:
- 2016 Census Housing Data
- Available for both Winnipeg and Manitoba Community Maps: Census Housing 2016
- Can be used in both the Query and Proximity Tools
- Creates a summary report that includes detailed information on Core Housing Need, Unsuitable housing, households spending more than 30% on accomodation by owner/rental status, household ownership, housing type, year of construction and major/minor repairs required.
- Limitations:
- Core Housing Need is not calculated for First Nation Communities, farming households, or households made up of students
- Due to significant data suppression and rounding by Statistics Canada, there are often inconsistencies within and between output tables.
- Available for both Winnipeg and Manitoba Community Maps: Census Housing 2016
- Low Income dot Mapping, 2016
- Available only for the Winnipeg Community Map: Low Income Dot Mapping 2016
- Can be used in both the Query and Proximity tools
- Creates a summary report:
- The count of individuals by age group (< 5, 6-17, 18-64, 65+) living in low income households
- Low income is based upon the Low-income measure, after tax (LIM-AT)
- WRHA Facilities:
- Available only for the Winnipeg Community Map (WRHA Facilities)
- Can be used in both the Query and Proximity Tools
- Generates a downloadable line-listing of facilities which can be viewed and manipulated in Excel.
- See the Health Care Facilities, Winnipeg Health Region layer in the Data Dictionary (Points of Interest tab) for more information
- Health Care Facilities, Manitoba:
- Available only for the Manitoba Community Map (Health Care Facilities, Manitoba)
- Can be used in both the Query and Proximity Tools
- Generates a downloadable line listing of facilities which can be viewed and manipulated in Excel
- See the Health Care Facilities, Manitoba layer in the Data Dictionary (Points of Interest tab) for more information on this layer.
- Schools:
- Available in both the Winnipeg Community Map and the Manitoba Community Maps
- Winnipeg Map: Schools 2016
- Manitoba Map: Mb Schools 2016
- Can be used in both the Query and Proximity Tools
- Generates a summary report (total schools, # of teachers, # of students by grade), as well as a downloadable line-listing of schools that can be viewed and manipulated in Excel
- See the Schools, 2016 Enrolment Year layer in the Data Dictionary (Points of Interest tab) for more information on this layer
- Available in both the Winnipeg Community Map and the Manitoba Community Maps