Terminology

Terms and Definitions

This document provides a standardized lexicon for the Data for Canada (D4C) project, categorized by data package and infrastructure component.

1. Statistical Data Package

Standard geographic areas from the 2021 Census of Population hierarchy, as defined by Statistics Canada.

• DGUID (Dissemination Geography Unique Identifier): An alphanumeric code used by Statistics Canada to uniquely identify a geographic area. It incorporates the vintage (year), type, and specific area code.

Administrative Areas

• Canada: The highest level of geography, covering the entire country.
• Province or Territory (PR): The primary political-administrative subdivisions of Canada.
• Census Division (CD): A group of neighboring municipalities joined together for the purposes of regional planning and managing common services.
• Census Subdivision (CSD): The general term for municipalities or areas treated as municipal equivalents for statistical purposes.
• Federal Electoral District (FED): An area represented by a Member of Parliament in the House of Commons.

Statistical Areas

• Aggregate Dissemination Area (ADA): A dissemination geography created by grouping existing dissemination areas, census subdivisions, or census tracts to achieve a target population.
• Census Metropolitan Area (CMA): An area consisting of one or more adjacent municipalities situated around a major urban core with a total population of at least 100,000.
• Census Agglomeration (CA): Similar to a CMA, but with a core population of at least 10,000.
• Census Tract (CT): Small, relatively stable geographic areas within CMAs and CAs that usually have a population between 2,500 and 8,000.
• Dissemination Area (DA): A small, stable geographic unit composed of one or more adjacent dissemination blocks.
• Dissemination Block (DB): An area bounded on all sides by roads and/or boundaries of standard geographic areas; the smallest unit of census geography.
• Economic Region (ER): A grouping of complete census divisions created as a standard geographic unit for analysis of regional economic activity.
• Population Centre (POPCTR): An area with a population of at least 1,000 and a density of 400 or more people per square kilometer.

3. Orthoimagery & Field Imagery Packages

Terms related to imagery processing and remote sensing.

• Orthoimagery: Aerial or satellite imagery geometrically corrected (“orthorectified”) such that the scale is uniform, allowing for accurate measurements of distance.
• Photogrammetry: The science of making measurements from photographs, used to generate 3D models and orthomosaics.