school_compare/pipeline/transform/models/marts/dim_location.sql

-- Mart: School location dimension — one row per URN, PostGIS-enabled
-- Geometry derived from GIAS easting/northing (British National Grid → WGS84).
-- For schools missing easting/northing, the geocode script backfills via Postcodes.io.

select
    s.urn,
    s.address_line1,
    s.address_line2,
    s.town,
    s.county,
    s.postcode,
    s.local_authority_code,
    s.local_authority_name,
    s.parliamentary_constituency,
    s.urban_rural,
    s.easting,
    s.northing,
    case
        when s.easting is not null and s.northing is not null
        then ST_Transform(ST_SetSRID(ST_MakePoint(s.easting::double precision, s.northing::double precision), 27700), 4326)
        else null
    end as geom,
    case
        when s.easting is not null and s.northing is not null
        then ST_Y(ST_Transform(ST_SetSRID(ST_MakePoint(s.easting::double precision, s.northing::double precision), 27700), 4326))
        else null
    end as latitude,
    case
        when s.easting is not null and s.northing is not null
        then ST_X(ST_Transform(ST_SetSRID(ST_MakePoint(s.easting::double precision, s.northing::double precision), 27700), 4326))
        else null
    end as longitude
from {{ ref('stg_gias_establishments') }} s
-- Must match dim_school's status and England filters exactly (the API
-- inner-joins the two).
where s.status_code in (1, 3)
-- coalesce, not a bare NOT IN: a null type code would make the predicate
-- null and drop the row silently. Unknown type is not grounds for exclusion.
and coalesce(s.school_type_code, -1) not in ({{ var('non_england_school_type_codes') | join(', ') }})
-- Welsh schools GIAS does not type as Welsh establishments (see vars).
and coalesce(s.local_authority_code, -1) not between {{ var('welsh_la_code_min') }} and {{ var('welsh_la_code_max') }}