Digitizing Early Postwar Canadian Census Tract Maps: Sources, Methods and Challenges
Bibliographic record
Abstract
At present, Canadian census tract boundaries are available in digital form for 1951 and at 5-year intervals for the 1976–2021 period; the 1956–66 census boundary files have not been digitized and associated data are not readily available for the pre-1971 period. This inhibits the mapping and analysis of neighbourhood change for a period of rapid urban and social transformation. To fill this gap, we digitized 1956–66 census tract boundaries from paper maps for all cities for which such data were disseminated. We adjusted 2006 boundaries to match georeferenced historical maps in concert with ancillary data, including topographic and cadastral maps. All decisions are documented in the files. Finally, printed profile tables for 1951 and 1956 were digitized for joining the boundary files. Researchers may use these datasets to explore, analyse and map geospatial trends in the Canadian population at the neighbourhood scale back to 1951.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.027 | 0.109 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.025 | 0.072 |
| Science and technology studies | 0.009 | 0.004 |
| Scholarly communication | 0.012 | 0.004 |
| Open science | 0.007 | 0.005 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.008 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".