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Andras Schmelczer 2026-07-03 18:39:34 +01:00
parent 1ee796b282
commit ab688243d7
36 changed files with 307 additions and 135 deletions
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8
pipeline/transform/area_crime_averages.py
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@ -5,7 +5,7 @@ The right pane shows each crime metric next to its area context: the mean
average-annual count (``"X (/yr, 7y)"``) across the selection's postcode sector (e.g.
``"E14 2"``), its outcode (e.g. ``"E14"``), and the nation. Crime is constant
within a postcode (the merge keys it on the postcode), so each postcode
contributes its single value weighted by how many properties sit in it — keeping
contributes its single value weighted by how many properties sit in it, keeping
every scope on the same property-weighted basis as the per-selection mean, so the
four numbers (this selection / sector / outcode / nation) are directly
comparable. The national figure here is an EXACT property-weighted mean, which is
@ -18,7 +18,7 @@ crime values from ``postcode.parquet`` and the per-postcode property weights fro
``properties.parquet`` mirrors exactly the two inputs the server loads, so the
result matches what the server used to compute (minus its u16 quantization loss).
Output schema — one row per area:
Output schema, one row per area:
scope : ``"national"`` | ``"outcode"`` | ``"sector"``
area : the outcode (``"E14"``) / sector (``"E14 2"``);
@ -43,7 +43,7 @@ SCOPE_NATIONAL = "national"
SCOPE_OUTCODE = "outcode"
SCOPE_SECTOR = "sector"
# Area label on the national row — it spans the whole country, so it has no code.
# Area label on the national row. It spans the whole country, so it has no code.
NATIONAL_AREA = ""
# Both merge outputs key on the canonical NSPL `pcds` postcode (spaced, e.g.
@ -71,7 +71,7 @@ def _weighted_mean(column: str) -> pl.Expr:
A null crime value is a genuine gap (the postcode's police force published no
usable data), not zero crime, so it must dilute neither the numerator nor the
denominator — exactly as the server's former estimator skipped NaN values.
denominator, exactly as the server's former estimator skipped NaN values.
Yields null when no postcode in the group has data for this type.
"""
weight = pl.col(_WEIGHT_COLUMN)