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Boundaries stay the same and data can be aggregated in both directionsboth forward and backward in time
Successor: This administrative unit did not change between geographic unit set versions.
Equivalent: Two units are equivalent between different geographic unit sets and do not need to be the same unit type, e.g., population and crop production units that are equivalent.
Seceded: Two units are equivalent between different geographic unit sets, are the same unit type, and can be part of separate countries, e.g., the admin 1 states of South Sudan seceded the admin 1 states of Sudan.
Name change: Only the name has changed between geographic unit set versions.
Promotion: An administrative unit becomes a higher-level administrative unit, e.g., Admin2 becomes Admin1.
Demotion: An administrative unit becomes a lower-level administrative unit, e.g., Admin1 becomes Admin2.
Boundaries change
Data can be aggregated forward in time
Merge: Parts of, or the whole of, two or more administrative units were joined together to create a new administrative unit version in the same geographic unit set.
Aggregate: Parts of, or the whole of, two or more administrative units were joined together to create a new administrative unit. However, unlike merge, this relationship doesn’t indicate anything about the relationship between the geographic unit sets.
Data can be aggregated backward in time
Split: One administrative unit was divided to form two or more new administrative units.
Split_demotion: One administrative unit was divided to form two or more new administrative units and the new units are demoted to a lower admin level.
Data can not be aggregated
Redistribute: Parts of more than one administrative unit were divided and redistributed into more than one new administrative unit.
Definition of one unit within another, e.g., admin1_0 indicates the unit is an admin1 within a specific admin 0.
Updating Geographic Unit Relationships in the FDW
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