flatland vs moorland

flatland

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

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

moorland

noun
  • Open land that has an acidic peaty soil and is mostly covered with heather or bracken. 

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