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LandClim Exports

LandClim exports provide Nordic pollen-sequence locations and REVEALS vegetation-reconstruction coverage. They are environmental context with their own observation units and time windows, not background decoration for an aDNA map.

Current Governed Surface

The checked-in normalized state contains:

Surface Count Observation unit
pollen site-sequence rows 492 dataset-specific site sequence
rows with supported numeric time bounds 482 site sequence with numeric BP posture
REVEALS grid cells 88 reconstructed vegetation coverage cell

The normalized artifacts are:

  • data/landclim/normalized/nordic_pollen_site_sequences.csv for tabular reuse;
  • data/landclim/normalized/nordic_pollen_site_sequences.geojson for site locations;
  • data/landclim/normalized/nordic_reveals_grid_cells.geojson for reconstruction coverage; and
  • data/landclim/normalized/landclim_summary.json for layer identities and counts.

These paths identify the normalized family authority. Scope-specific copies in report bundles remain product members whose lineage leads back to these records; copying a feature into a map directory does not transfer ownership of its sequence identity or temporal posture.

flowchart LR
    Datasets["PANGAEA LandClim datasets"] --> Sites["492 site-sequence rows"]
    Datasets --> Grids["88 REVEALS grid cells"]
    Sites --> Time["482 rows with numeric BP bounds"]
    Sites --> Context["pollen-site context layer"]
    Grids --> Context
    Time --> Compare["qualified temporal comparison"]

Site Rows And Grid Cells Are Not Interchangeable

A site row identifies one dataset-specific pollen sequence at a location and can carry its own time window, source URL, and sequence metadata. A grid cell summarizes published REVEALS coverage and can combine variables, datasets, and multiple time windows. One site can contribute to broader reconstruction context; that relationship does not make the site and cell the same record.

Names can recur across LandClim datasets. Stable record_id values retain the dataset and location identity needed to avoid merging similarly named site sequences by display label alone.

Temporal Reading

Numeric time_start_bp and time_end_bp values support interval-aware filtering for the 482 qualified rows. They do not guarantee equal dating resolution, identical sampling intervals, or event-level contemporaneity with an aDNA sample. The remaining rows are not zero-dated; their numeric posture is unavailable under the normalized contract.

REVEALS grid cells can span many windows. Use their declared window coverage rather than collapsing a cell to a single date. A cell's broad reconstruction span must not be treated as a sample-owned chronology.

Worked Record: Aal Præstesø

The normalized LandClim feature for Aal Præstesø demonstrates the minimum portable site-sequence claim:

Field Governed value Interpretation
record_id 897303:Aal Præstesø:55.637778:8.257222 dataset, label, and reported position form the retained record identity
country Denmark publication grouping, not the scientific identity
geometry 8.257222, 55.637778 GeoJSON longitude then latitude
source https://doi.org/10.1594/PANGAEA.897303 LandClim dataset lineage
interval 100-350 BP coverage attached to this site-sequence row
observation unit one site sequence not one pollen grain, sample event, or REVEALS cell

The interval permits interval-aware filtering at the site-sequence level. It does not state that every observation within the sequence has that date or that another record overlapping 100-350 BP represents the same event. If the feature is exported without its record_id, source DOI, and observation unit, the remaining name and point are insufficient to reconstruct that meaning.

flowchart LR
    Dataset["PANGAEA 897303"] --> Sequence["Aal Præstesø site sequence"]
    Sequence --> Place["reported point in Denmark"]
    Sequence --> Window["100-350 BP coverage"]
    Sequence --> Layer["LandClim pollen context"]
    Window -. "not an event date" .-> Layer

Reuse Contract

Keep record identity, source DOI, geometry type, observation unit, dataset, time bounds and label, record count, and popup/source details with each row. When aggregating, keep site sequences separate from grid cells and state whether the denominator is 492 site rows, 482 numerically qualified rows, or 88 coverage cells.

Continue to LandClim source guidance for acquisition and normalization, maps for layer interpretation, and chronology guidance for cross-family time claims.