time_semantics_shared

Shared Time Semantics For Danish Grunddata

This note is a shared contract for temporal interpretation in manifests and workflows.

Core Time Axes

• Valid time (virkningstid): when data is valid in the real world.
• Transaction time (registreringstid): when data was recorded in the register.

Common Fields

• virkningFra, virkningTil
• registreringFra, registreringTil

NULL in end fields typically means open-ended validity/current registration depending on context.

File Download Modes (General Pattern)

• Current: latest active state view.
• Temporal: valid-time history using current registration state.
• Bitemporal: both valid-time and registration-time history.

Interpretation Rule

Do not mix time concepts implicitly. Always state which question is being answered:

1. What was valid at time T?
2. What was known/registered at time R?

Course Reference

Extended student explanation and examples:

• TIME_IN_GIS_DAGI_STUDENT_NOTE.md