Geography And Administrative Classifications
This page explains geography and administrative reference data used by establishments, local authorities and postcode-derived location context.
Scope
This view focuses on:
- local authorities and local authority groups;
- government office regions and GSS local authority mappings;
- establishment geography columns;
- postcode-derived geography through
GeoData; - postcode and location average coordinates.
It does not show audit tables or staging tables marked as inactive.
How To Read This Model
- Local authority is reference data with identity implications, not just geography.
- Establishments store many geography codes directly for main and contact addresses.
GeoDatamaps postcodes to administrative and statistical geographies.- Country fields reuse
Nationality, which is a legacy naming mismatch. - Some geography relationships are derived through postcode or mapping procedures rather than direct foreign keys.
Application-Derived Insights
- Local authority participates in establishment identity, establishment-number scoping, user scope and group relationships.
- Postcode-derived geography supports display, search, filtering and classification.
- Target modelling should separate manually held geography, postcode-derived geography and imported/reference geography.
- Naming mismatches such as country values stored through
Nationalityshould be corrected or clearly abstracted in public models. - Region is not supplied by ONS. It is derived internally:
LocalAuthoritymaps toGovernmentOfficeRegionviaLaGorMapping. When an establishment’s region appears on a record or extract, it comes from this LA-to-GOR lookup, not from the ONS Postcode Directory import. The ONS integration supplies postcode-to-geography codes (ward, LSOA, MSOA, parliamentary constituency, district, urban/rural) but does not supply region. - GSS local authority codes are similarly derived internally via
LaGssMappingrather than imported directly from ONS.
Local Authority And Region
LocalAuthority
LocalAuthority is the core administrative authority reference table.
Business-friendly pattern:
For this establishment, group or user scope,
which local authority context applies?
LocalAuthorityGroup
LocalAuthorityGroup groups local authorities into broad subsets.
Business-friendly pattern:
For this local authority,
which national or subset grouping does it belong to?
LaGorMapping
LaGorMapping maps local authorities to Government Office Regions. This is the mechanism by which establishment region values are produced: the establishment’s LA code is looked up in this table to derive the corresponding Government Office Region code. Region is therefore an internally derived value, not a field populated by the ONS Postcode Directory import.
Business-friendly pattern:
For this local authority,
which Government Office Region should be derived or defaulted?
LaGssMapping
LaGssMapping maps local authorities to GSS local authority codes.
Business-friendly pattern:
For this local authority,
which GSS local authority code should be used?
Postcode-Derived Geography
GeoData
GeoData maps a postcode to administrative and statistical geography classifications.
Business-friendly pattern:
For this postcode,
which geography and administrative classification codes apply?
Geography Code Lists
Administrative ward, LSOA, MSOA, parliamentary constituency and urban/rural tables provide geography code-list values.
Business-friendly pattern:
For this geography code,
what geography or administrative area does it describe?
Reading This Diagram
These ERDs are explanatory views. Geography values may be held, imported, mapped or derived, so target ownership rules need to distinguish those sources.