school_compare/backend/localities.py

"""Curated London localities, defined by the postcode districts they cover.

The GIAS `town` field puts 1,819 London schools under the single value
"London", so it cannot answer "schools in Battersea" — a query that appears in
the Search Console baseline. No single field can: parliamentary constituency
gives Battersea but not Canary Wharf; postcodes.io's admin_ward gives Canary
Wharf but not Battersea; neither gives Clapham or Shoreditch, which are postal
and colloquial rather than administrative.

So this is curated. Where a locality ends is a judgement, not a fact, and a
reviewable file is the honest place for a judgement. No new ingestion is
needed — the corpus already carries postcodes.

This is the canonical copy. `pipeline/transform/seeds/locality_outcodes.csv`
mirrors it for anyone querying the warehouse directly; the backend image does
not contain `pipeline/`, which is why the module rather than the seed is
canonical. Same arrangement as `backend/gias_codes.py`.

A locality whose outcodes hold fewer than MIN_SCHOOLS schools is not
published, so a typo produces no page rather than an empty one. Places that
fail that check are logged at startup, because a locality you meant to publish
quietly not appearing is the failure worth hearing about.

Two rules for anything added here.

**Sub-borough districts only.** A London borough is a local authority and
already has a page at /schools/authority/[la] covering all of its schools; a
locality defined by two or three outcodes would be a partial, near-duplicate
subset of it. Hackney, Islington, Greenwich and Ealing were all in the first
draft for that reason and have been removed.

**The slug must not match a GIAS town.** "Richmond" did — GIAS has a Richmond
in North Yorkshire with 37 schools — so the London one could never publish.
The registry skips any locality that collides and logs it.
"""

# slug -> (display name, outcodes)
LOCALITY_OUTCODES: dict[str, tuple[str, tuple[str, ...]]] = {
    "battersea":     ("Battersea",     ("SW11",)),
    "canary-wharf":  ("Canary Wharf",  ("E14",)),
    "clapham":       ("Clapham",       ("SW4",)),
    "shoreditch":    ("Shoreditch",    ("EC2A", "E1")),
    "peckham":       ("Peckham",       ("SE15",)),
    "brixton":       ("Brixton",       ("SW2", "SW9")),
    "camden-town":   ("Camden Town",   ("NW1",)),
    "wimbledon":     ("Wimbledon",     ("SW19",)),
    "putney":        ("Putney",        ("SW15",)),
    "fulham":        ("Fulham",        ("SW6",)),
    "chiswick":      ("Chiswick",      ("W4",)),
    "stratford":     ("Stratford",     ("E15",)),
    "walthamstow":   ("Walthamstow",   ("E17",)),
    "tooting":       ("Tooting",       ("SW17",)),
    "dulwich":       ("Dulwich",       ("SE21", "SE22")),
}