champaign vs flatland

champaign

adj
  • Pertaining to open countryside; unforested, flat. 

flatland

noun
  • An urban region with many flats or apartments to rent. 

  • Synonym of plain: land of relatively constant altitude, usually exclusive of forests, deserts, and wastelands. 

How often have the words champaign and flatland occurred in a corpus of books? (source: Google Ngram Viewer )