{
  "schema": "SOVRIENT_AIS_MARITIME_SLICE_V1",
  "artifact_role": "public_governance_seed_over_real_local_source",
  "slice_id": "ais_hampton_roads_2025-09-15_bbox",
  "generated_utc": "2026-04-04T17:48:00Z",
  "observed_at_utc": "2025-09-15T23:59:59Z",
  "verified_at_utc": "2026-04-04T17:48:00Z",
  "area_name": "Hampton Roads / lower Chesapeake approaches",
  "coverage": {
    "provider": "NOAA Office for Coastal Management / Marine Cadastre",
    "dataset_name": "ais-2025-09-15.csv.zst",
    "dataset_class": "point_data",
    "source_ref": "noaa_csv2025:ais-2025-09-15.csv.zst",
    "data_as_of": "2026-04-04",
    "land_based_open_ais": true,
    "live": false,
    "satellite": false,
    "coverage_note": "Real bounded clip from the official NOAA 2025 daily land-based AIS file.",
    "public_manifest_url": "https://www.sovrient.com/data/maritime_ais_hampton_roads_manifest_latest.json",
    "public_clipped_csv_url": "https://www.sovrient.com/data/maritime_ais_hampton_roads_2025-09-15_bbox.csv.gz"
  },
  "stats": {
    "observation_count": 201376,
    "unique_mmsi_count": 463,
    "first_timestamp_utc": "2025-09-15 00:00:00",
    "last_timestamp_utc": "2025-09-15 23:59:59",
    "representative_mmsi": {
      "mmsi": "368231430",
      "observation_count": 1230,
      "vessel_name": "DELAWARE"
    },
    "top_vessel_types": [
      {"value": "52", "count": 48576},
      {"value": "37", "count": 32406},
      {"value": "31", "count": 21414},
      {"value": "70", "count": 18914},
      {"value": "36", "count": 10695}
    ]
  },
  "governance_seed_note": "The source clip is real and publicly exposed through the manifest and clipped CSV. The selection, comparison, source-weight, and exclusion records below are a bounded initial governance seed over that local slice, not a full port-scale anomaly adjudication pass.",
  "selection_records": [
    {
      "selection_id": "sel-track-1",
      "subject_kind": "track_fragment",
      "subject_id": "mmsi-368231430-fragment-1",
      "selected_variant": "mmsi:368231430:representative-fragment",
      "competing_variants": [
        "mmsi:368231430:alternate-fragment"
      ],
      "reason": "track_fragment_selected_for_governed_replay",
      "details": [
        "bounded_slice=ais_hampton_roads_2025-09-15_bbox",
        "representative_vessel_name=DELAWARE",
        "dataset_class=point_data"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    }
  ],
  "comparison_records": [
    {
      "comparison_id": "cmp-track-1",
      "subject_kind": "track_fragment",
      "subject_id": "mmsi-368231430-fragment-1",
      "representative_variant": "mmsi:368231430:representative-fragment",
      "candidate_source": "noaa_open_ais_daily_clip",
      "comparison_type": "position_continuity_check",
      "within_threshold": true,
      "result": "comparison_within_threshold",
      "ok": true,
      "dt_sec": 60.0,
      "dist_km": 0.9,
      "details": [
        "check=position_continuity",
        "threshold=max_segment_distance_km"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    },
    {
      "comparison_id": "cmp-track-2",
      "subject_kind": "track_fragment",
      "subject_id": "slice-duplicate-identity-seed",
      "representative_variant": "slice:duplicate-identity-seed",
      "candidate_source": "noaa_open_ais_daily_clip",
      "comparison_type": "duplicate_identity_check",
      "within_threshold": false,
      "result": "same_source_duplicate_observed",
      "ok": false,
      "dt_sec": 15.0,
      "dist_km": 4.2,
      "details": [
        "check=duplicate_identity",
        "effect=ambiguous"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    },
    {
      "comparison_id": "cmp-track-3",
      "subject_kind": "track_fragment",
      "subject_id": "slice-speed-feasibility-seed",
      "representative_variant": "slice:speed-feasibility-seed",
      "candidate_source": "noaa_open_ais_daily_clip",
      "comparison_type": "speed_feasibility_check",
      "within_threshold": false,
      "result": "comparison_outside_threshold",
      "ok": false,
      "dt_sec": 30.0,
      "dist_km": 6.1,
      "details": [
        "check=speed_feasibility",
        "effect=excluded"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    }
  ],
  "source_weight_records": [
    {
      "weight_id": "weight-track-1",
      "subject_kind": "track_fragment",
      "subject_id": "mmsi-368231430-fragment-1",
      "representative_variant": "mmsi:368231430:representative-fragment",
      "ranked_variants": [
        "mmsi:368231430:representative-fragment",
        "mmsi:368231430:alternate-fragment"
      ],
      "source_weights": {
        "noaa_open_ais_daily_clip": 1,
        "noaa_ais_vessel_tracks_2025": 2
      },
      "reason": "stable_sort_source_weight_declared",
      "details": [
        "weight_semantics=lower_rank_is_stronger"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    }
  ],
  "exclusion_records": [
    {
      "exclusion_id": "exclude-coverage-1",
      "subject_kind": "slice",
      "subject_id": "ais_hampton_roads_2025-09-15_bbox",
      "reason": "coverage_limit_disclosed",
      "details": [
        "land_based_open_ais=true",
        "live=false",
        "satellite=false"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    },
    {
      "exclusion_id": "exclude-track-3",
      "subject_kind": "track_fragment",
      "subject_id": "slice-speed-feasibility-seed",
      "reason": "speed_feasibility_failed",
      "details": [
        "check=speed_feasibility",
        "effect=excluded"
      ],
      "path": [
        "slice_root",
        "z_anomaly_review_required"
      ],
      "policy_artifact_ref": "maritime-ais-policy-v1"
    }
  ],
  "what_this_does_not_prove": [
    "that the slice is a live NOAA AIS feed",
    "that the slice has global maritime coverage",
    "that one anomaly proves spoofing or malicious behavior"
  ]
}