In 1826 Johann Heinrich von Thünen published the first part of Der isolirte Staat, The Isolated State. He imagined a state with one city as its only market, surrounded by rings of farming. What is grown in each ring depends on its distance from the market. In German the model is known as the Thünensche Ringe, Thünen’s rings.
The national biography says that Thünen gave important impulses to location theory and to economic geography. Teaching material for upper secondary geography still presents the rings as a thinking model zur Erklärung räumlicher Ordnungsmuster in der Landwirtschaft, for explaining spatial patterns in farming.