I'm trying to find and merge German city-level data from various time periods: ~1900, ~1930 and ~1990.
Obviously some cities merged, new places were founded after 1900, and again others are in nowadays Poland or France. I am mainly interested in finding data on population densities and further demographics, but would need to know in detail whether some data point pertains to exactly the same unit of observations.
Example: Older data might have an entry for "Ebingen" in Baden-Württemberg. In 1975 Albstadt was founded and Ebingen bekame a part of Albstadt so more recent data will have Albstadt not Ebingen, but Albstadt also contains other places.
What I need:
Is there any public dataset available that
- provides information on such changes,
- provides pre-war demographics (population etc.), and ideally
- links pre-war town names to today's municipality-IDs (GKZ)?
If there's data fitting only one of these points I'd be grateful too.