Unit 04: historical regional teaching data

Source: Federal Statistical Office and the statistical offices of the German
states; Regional Database Germany / GENESIS Regional Atlas table AI001 and
harvest-statistics table 115-46-4. Regional Database:
https://www.regionalstatistik.de/genesis/online/

These are English teaching translations prepared for the GeoMOER Data Analysis
course, not new official English exports. Source headings and regional
descriptors are translated; proper place names are retained. The English
crosswalk maps source headings/labels to their teaching translations.

Required inputs (save in your project's Data/ folder):
- regional-land-use-1996-2014.txt: 5,250 region-year records, four introductory
  lines, header line 5, seven columns, percentages of total reporting area.
  Settlement includes transport. Reporting years are not a complete annual
  series. This is separate from Unit 03's 2024 state table.
- regional-crop-yields-1999-2015.txt: 8,925 region-year records, six introductory
  lines, header line 7, 13 columns, five footer lines. Crop yields are dt/ha
  (1 dt = 100 kg). The original copyright and reproduction statement is retained
  in the footer: reproduce/distribute with attribution to the source.
Both text files use UTF-8, semicolons and decimal commas. Original values,
IDs, years, row order, indentation and source symbols are preserved.

Optional prepared checkpoints (save in Output/ if substituting for your result):
- lu_clean.rds: 5,250 rows, nine columns, generated by the Unit 04 land-use exercise Rmd;
  reused in Units 05-06.
- cp_clean.rds: 8,925 rows, 15 columns, prepared to the Unit 04 assignment schema;
  reused in Unit 07. This dataset does not include a solution script.
IDs/place names are text, years integer, measurements numeric. Metadata follows
the lessons' conservative English label rules. Unknown administrative types
remain NA (1,130 land-use rows; 1,921 crop rows), not guessed classifications.
All numeric cells match the former checkpoints, including NA and explicit zero.

The symbols -, . and / have distinct source forms. The course retains original
source cells separately and uses numeric NA as an explicit teaching policy;
it does not claim that these source symbols have the same official meaning.
Keep original tokens before conversion. Explicit 0,0 values remain zero.

Unmodified source exports and prior RDS versions remain in the instructor's
provenance archive. They are not additional required learner downloads.