Boundary Exports

Boundary exports define the geographic framing used by Nordic and country products. They make scope selection reproducible while remaining explicitly outside the scientific evidence weighting.

Current Governed Surface

data/boundaries/normalized/nordic_country_boundaries.geojson contains four MultiPolygon features:

Country	Publication use
Sweden	country membership, map framing, and Nordic composition
Norway	country membership, map framing, and Nordic composition
Finland	country membership, map framing, and Nordic composition
Denmark	country membership, map framing, and Nordic composition

The collection summary pins the boundary family to collection version v66, retrieval date 2026-06-22, acquisition method collector_pipeline, and captured and normalized SHA-256 digests. Those values identify the geometry state used by publication; they do not assign historical meaning to the polygons.

flowchart LR
    Source["captured boundary source"] --> Normalize["four governed country polygons"]
    Normalize --> Registry["publication geography registry"]
    Registry --> Nordic["Nordic scope"]
    Registry --> Countries["Sweden, Norway, Finland, Denmark scopes"]
    Nordic --> Filter["membership and viewport framing"]
    Countries --> Filter
    Filter -. no scientific weight .-> Evidence["aDNA, pollen, and archaeology layers"]

Scope Is A Product Decision

A feature can be selected into a country bundle because its declared geometry falls within the governed country scope. That membership decision does not prove historical nationality, cultural affiliation, or source completeness. Modern country geometry is publication framing applied to evidence whose own locality and chronology remain independently governed.

Boundary changes can alter membership without changing the scientific source record. Release comparison therefore distinguishes geometry-driven scope change from evidence change. The feature identifier and parent-child subset validation reveal which interpretation applies.

Membership Is A Recomputable Relation

Country membership is not copied into source evidence as permanent truth. It is derived from three versioned inputs:

membership = evidence geometry + boundary geometry + selection rule

Input change	What changed	What did not necessarily change
evidence coordinate corrected	the record's spatial claim	boundary or scientific identity
boundary geometry replaced	publication scope geometry	source locality, chronology, or taxonomy
containment rule revised	product selection semantics	captured source bytes
product country list revised	declared publication scope	validity of records outside that scope

flowchart LR
    Evidence["evidence geometry and precision"] --> Relation["declared membership rule"]
    Boundary["versioned country geometry"] --> Relation
    Product["named geographic scope"] --> Relation
    Relation --> Member["included with reason"]
    Relation --> NonMember["retained outside scope"]

This separation explains why a record can move between country products without a new scientific observation. A release note must identify which of the three inputs changed instead of reporting every membership change as new or removed evidence.

Edge And Precision Cases

• A point near a border retains its coordinate provenance and precision; the boundary does not make an approximate point exact.
• A broad regional locality cannot be forced into country membership merely because a representative coordinate falls inside a polygon.
• Offshore, disputed, or changed geometry requires an explicit product rule; visual containment is not a substitute.
• Absence from a country bundle can mean out of scope even when the evidence remains present in a broader product.

Reuse Contract

Carry the boundary GeoJSON, collection version and hashes, country identifiers, geometry role, publication geography registry, and selection rule with any scope-derived extract. Keep boundary features in the framing role; do not add them to evidence counts, ranking weights, or historical inference.

Continue to boundary source guidance for collection identity, maps for rendering behavior, and reports for scope lineage.