FUA pilot geography contract

# European FUA pilot geography contract v0

**Queue action:** A8  
**Lane:** D — data/product foundations  
**Evidence status:** RESEARCH

## Objective

Pin one official, reproducible European Functional Urban Area geography artifact and a heterogeneous eight-FUA QA panel. This contract establishes territorial identifiers and geometry gates only. It does not produce a metric, comparison, ranking or public claim.

## Authoritative inputs

The source is Eurostat GISCO's Urban Audit 2024 distribution. The pinned artifact is the 1:100,000 FUA boundary GeoJSON in ETRS89 / LAEA Europe (`EPSG:3035`). The accompanying GISCO metadata says the dataset incorporates Census 2021 and commuting data and derives geometry from EuroGeographics EuroBoundaryMap 2025 using Local Administrative Units referenced to 1 January 2024.

Reproducibility is anchored by the exact download URL, byte size, SHA-256 digest, HTTP metadata and feature count recorded in `sources/fua_pilot_2024.json`. The 46 MB source geometry is intentionally not vendored.

## Rights gate

This artifact is approved only for internal, non-commercial research. The official metadata requires the acknowledgement `Administrative boundaries: © EuroGeographics` and states that the generalized dataset must not be used commercially. The manifest therefore records commercial reuse as `HOLD`.

No public or commercial redistribution of these geometries is authorized by this contract. Before such use, obtain explicit licence clearance or substitute a source whose terms permit the intended use.

## Pilot selection

The eight FUAs are Wien, Athina, Madrid, Helsinki, Paris, Grenoble, Amsterdam and Warszawa. They span eight countries and include both Polygon and MultiPolygon geometries. This is a processing QA panel, not a statistically representative sample and not an assessment of those territories.

Stable identity is the GISCO `URAU_CODE`, never the display name. The contract also pins the observed name, country, `NUTS3_2024` field and geometry type so upstream changes fail visibly.

## Validation gates

`pipelines/fua_pilot_contract.py` fails closed unless:

1. the manifest is RESEARCH and identifies the official HTTPS distribution endpoints;
2. the artifact identity fields, CRS, provenance, rights restriction and required acknowledgement are present;
3. the pilot contains five to eight unique FUA identifiers with category suffix `F`;
4. the downloaded bytes match the pinned size and SHA-256 digest;
5. the file is a GeoJSON FeatureCollection declaring EPSG:3035 with the pinned total feature count;
6. every pilot identifier occurs exactly once and its pinned properties match;
7. every pilot geometry is non-empty, valid and Polygon or MultiPolygon.

Run the unit suite with:

```bash
python -m unittest tests/test_fua_pilot_contract.py
```

Verify a freshly downloaded official artifact with:

```bash
python pipelines/fua_pilot_contract.py \
  sources/fua_pilot_2024.json \
  /path/to/URAU_RG_100K_2024_3035_FUA.geojson
```

Install `requirements-fua.txt` before artifact verification. Manifest-only validation uses the Python standard library.

## Limitations and stop conditions

- The upstream file may be revised in place. A changed byte size, hash, ETag, feature count or selected feature must be reviewed rather than silently accepted.
- GISCO's `AREA_SQM` field is not interpreted here because its numerical semantics have not been independently confirmed for this contract.
- Valid geometry and stable IDs do not establish suitability for a specific metric, population weighting, longitudinal comparison or product use.
- Evidence remains RESEARCH until the relevant scientific and publication gates are independently satisfied.