T-02: Provenance & Quality Layer

T-02: Provenance & Quality Layer
W3C PROV-O
The W3C Provenance Ontology. Every data submission, validation event, and agent action is recorded as a PROV-O graph: 
prov:Entity (the data), 
prov:Activity (what happened), 
prov:Agent (who did it), 
prov:wasGeneratedBy, 
prov:wasAttributedTo.
ISO 8000-220:2025 — Data Quality
International standard for data quality management. Used for metadata quality dimensions: completeness, accuracy, consistency, timeliness. CTH maps these to field-specific thresholds in the SHACL profile.
cth:FieldDataQuality SHACL Profile (CTH-original)
SHACL shapes that enforce EUDR-specific and Andean-specific quality rules at ingestion. Key shapes:
Shape
Rule
Rationale
cth:GpsPrecision
Polygon vertices must have ≥6 decimal place precision
EUDR Article 9 requires parcel identification; 5dp = ~1m accuracy; 6dp = ~10cm
cth:DeforestationDataVintage
IDEAM reference raster must be ≤24 months old
EUDR requires current deforestation status; stale data invalidates DDS
cth:IotCalibration
IoT soil/weather sensors must have calibration certificate ≤180 days old
Sensor drift; CSRD ESRS E4 requires traceable measurement
cth:AndeanGpsLock
GPS receiver must record ≥90 second lock wait per polygon vertex
Mountain terrain + tree canopy causes GPS multipath error; 90s reduces error below EUDR threshold
Ledger Integrity
The governance ledger is an append-only Postgres table with rolling SHA-256 hashes. Each entry hashes the previous entry's hash (blockchain-like chain). KERI (Key Event Receipt Infrastructure) anchoring is used for cross-organisational verifiability — validators can independently verify ledger integrity without trusting CTH's infrastructure.