Boundary version
Location, geometry, source, version and effective dates
Boundaries, Coordinates & Time
Coordinates state whether they are geographic centroids, administrative centroids, representative points, facilities or exact points. Boundaries are separately sourced and versioned.
Preserve historical geography with historical data.
Coordinate system
Validate and transform to a canonical CRS while preserving metadata
Geometry checks
Self-intersection, range, projection, duplicates and mismatch
Historical map
Use the boundary effective for the selected data year
Review state
Invalid geometry is flagged for human review—not deleted
PRINCIPLE