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SEAD

SEAD contributes environmental-archaeology sites to the Nordic evidence atlas. Those sites are not static. Many are connected to dating ranges or relative periods in SEAD's relational database, while others still have no usable numeric chronology. The repository preserves that unevenness instead of forcing every site into one temporal category.

This source family stays an archaeology context layer: it is strong contextual evidence for nearby activity and chronology review, but it is not sample-owned proof of one lake event.

The practical rule is simple: use the governed Sweden discovery surface in the Nordic Atlas, then return to the normalized temporal-evidence and site-inventory products when auditing its source. The discovery surface keeps every Swedish site, preserves each eligible linked interval, and represents missing numeric chronology explicitly rather than as a static or timeless point.

Current Evidence State

The current governed full-evidence run is sead-full-evidence-39bfff6a-ce80714e (sha256:ce80714e4c9e9974b24913e5da50f49854670ed642879c1ca5076499e1d56725). Its denominators are:

Governed population Count Interpretation
source tables 61 complete captured relational table set
sites in the Nordic bounding-box review 2,195 country-decision denominator
assigned four-country sites 2,069 SE 1,925, DK 59, NO 45, FI 40
sites requiring country review 103 retained outside assigned publication membership
unassigned sites 23 retained without a governed country assignment
atlas SEAD features 11,796 2,069 four-country site features plus 9,727 Swedish chronology-discovery features; not a distinct-site count
chronology claims 25,109 14,264 comparable, 10,144 context-only, 60 refused by the numeric BP contract, 641 unresolved
source-native observations 177,763 quantitative observation denominator
source-native taxon relations 1,974 preserved source taxonomy, not accepted cross-source classification
dimension relations 2,639 explicit source-native measurement dimensions
eligible / refused propagation events 0 / 177,763 refused: source_classification_not_accepted

Site, feature, claim, observation, relation, and event counts are different units. The atlas may display SEAD chronology and source-native detail, but it must not turn the refused event population into migration or propagation evidence.

From A Relational Database To A Map Point

A SEAD date belongs to a chain of records, not directly to a coordinate. The collector follows that chain and retains the intermediate identities before deriving a site envelope.

flowchart LR
    Site["site"] --> Group["sample group"]
    Group --> Sample["physical sample"]
    Sample --> Entity["analysis entity"]
    Entity --> Value["analysis value"]
    Value --> Dating["analysis dating ranges"]
    Entity --> Relative["relative dates and ages"]
    Entity --> Model["modelled entity ages"]
    Entity --> Geochron["geochronology"]
    Entity --> Dendro["dendrochronology"]
    Site --> Reference["site, sample-group, dataset, and period references"]
    Reference --> Bibliography["bibliography"]
    Dating --> Evidence["record-level temporal evidence"]
    Relative --> Evidence
    Model --> Evidence
    Geochron --> Evidence
    Dendro --> Evidence
    Evidence --> Timeline["time-filterable chronology layer"]
    Evidence --> Envelope["coarse site envelope"]
    Envelope --> Point["site-inventory layer"]

The site envelope remains a publication convenience for ranking and overview. The temporal-evidence layer is the appropriate product for chronological navigation: each feature keeps one interval and the identifiers of all source rows grouped into it. For sample-level reasoning, continue into raw/nordic_sites.json; a mapped chronology feature is more precise than a site envelope but is still contextual evidence, not proof of a lake event.

Site Posture And Chronology Posture

Numeric interval and context

A site has a normalized time_start_bp and time_end_bp derived from captured temporal relations. It may also retain the original relative-period labels and uncertainty notes. The atlas can test interval overlap for this site.

For example, Agerod V (4237) is published with a site envelope of 7000–10000 BP. That makes it eligible for a map window that overlaps the interval. It does not prove that every Agerod V observation belongs to every year in that span.

Source label without numeric support

A site can have source period language but no stable numeric interval accepted by the repository. A self-encoded label such as CAL_1242_AD- can be converted because the bounds and era are present in the source value. A broad label such as Quaternary cannot be placed on the slider by name alone. In the current snapshot, such sites are part of the unresolved site population rather than a separate numeric chronology layer.

Unresolved

The captured relations do not support either an eligible numeric envelope or a useful normalized period label. The site remains valid spatial context. A null time value means “not resolved under this contract,” not 0 BP, “modern,” or “undated in the upstream database.”

flowchart TD
    Relations["captured temporal relations"] --> Numeric{"eligible numeric bounds?"}
    Numeric -->|yes| Timed["numeric interval and context"]
    Numeric -->|no| Label{"source period label?"}
    Label -->|yes| Context["contextual label only"]
    Label -->|no| Unresolved["unresolved"]
    Timed --> Slider["numeric timeline filtering"]
    Context --> Reading["popup and source interpretation"]
    Unresolved --> Reading

How The Atlas Timeline Treats SEAD

The Nordic Atlas exposes one governed Sweden archaeology discovery layer. It contains all 1,925 assigned Swedish SEAD sites as 8,172 linked numeric chronology features plus 1,555 explicitly unresolved site features. Once a reader narrows the time window:

  1. numeric features remain visible only when their own linked interval overlaps the selected window; and
  2. unresolved features are withheld because overlap is unknown.

This is different from declaring unresolved sites absent from the selected period. The interface is refusing a comparison it cannot make. Static layers such as boundaries are unaffected by this rule.

The Nordic normalized site and temporal-evidence products remain available for audit and reuse. They are not loaded beside the discovery layer because doing so would duplicate the same SEAD population and obscure the governed discovery contract.

Compare SEAD With LANDCLIM And AADR Carefully

All three families can appear on one numeric BP timeline, but their observation units remain different.

Source family Timed map unit What interval overlap supports What it does not support
SEAD temporal evidence grouped linked chronology interval one or more identified source chronology rows overlap the selected window the chronology proves a lake event or every record at the site is contemporaneous
LANDCLIM pollen site-sequence interval the sequence covers part of the selected window direct association with a nearby archaeological site
AADR dated human sample or governed locality descendant the sample chronology overlaps the window identity between a sample and a nearby site

Temporal overlap is therefore a candidate relation for investigation, not a join key. Keep source identity, spatial distance, interval basis, and observation unit with any cross-source statement.

The 126 Captured Non-Members

The difference between 2,195 bounding-box review rows and 2,069 assigned site points is a country-membership decision. The 126 non-members comprise 103 rows requiring country review and 23 unassigned rows. They retain source identities and coordinates without being silently promoted into one of the four governed publication countries.

flowchart LR
    Capture["2,195 captured sites"] --> Coordinate{"inside a governed country geometry?"}
    Coordinate -->|assigned| Map["2,069 four-country site features"]
    Coordinate -->|review| Review["103 country-review rows"]
    Coordinate -->|unassigned| Retained["23 unassigned rows"]
    Capture --> Chronology["25,109 chronology claims"]
    Chronology --> Comparable["14,264 comparable claims"]
    Chronology --> Ineligible["10,144 context-only + 60 refused + 641 unresolved"]

This is not deduplication or evidence deletion. A boundary or publication scope change must reevaluate the same 23 identities.

Appropriate Claims

SEAD supports:

  • finding environmental-archaeology sites near a lake, pollen sequence, or aDNA locality under a declared distance rule;
  • navigating 14,264 comparable chronology claims through interval-preserving features;
  • retaining relative-period language for human interpretation without inventing numeric bounds;
  • identifying sites whose bibliography or deeper relational evidence merits inspection; and
  • comparing regional evidence coverage while keeping capture and publication denominators separate.

SEAD does not by itself support:

  • treating proximity as direct association;
  • treating a site envelope as a sample or event date;
  • assigning dates to unresolved sites from neighbours or broad historical expectations;
  • interpreting database density as past population or activity; or
  • merging SEAD and RAÄ into one archaeology truth set.

Continue with Sweden archaeology site discovery for the complete population, readiness order, artifact set, and interpretation contract.

Governing Surfaces

Surface Responsibility
data/sead/raw/nordic_sites.json captured site rows, relational inventories, source counts, and acquisition lineage
data/sead/normalized/nordic_environmental_sites.geojson mapped features, temporal fields, popup evidence, and country membership
data/sead/normalized/nordic_temporal_evidence.geojson mapped record-level chronology groups used by the atlas time filter
data/sead/derived/sweden_archaeology_site_discovery.json complete Swedish site registry and evidence-readiness contract
data/sead/derived/sweden_archaeology_site_discovery.geojson Atlas-ready exact intervals and explicitly unresolved Swedish sites
data/sead/review/temporal_review.json row-level comparison posture and capture denominators
data/sead/review/access_model.json mirrored versus upstream-only access boundary
data/sead/review/evidence_legibility_review.json interpretability and publication risk
data/sead/review/recovery_requirements.json remaining evidence gaps and their satisfaction signals
data/source_spatiotemporal_posture_registry.json cross-source summary of allowed spatial and temporal use

The SEAD handbook provides a step-by-step reading method. The SEAD exports guide explains which artifact to use for analysis, review, and publication.