Decumanus

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Decumanus is a term from the Roman land surveying . It describes the vertical lines in a rectangular surveying system.

Decumanus of Palmyra
Scheme of Decumanus and Kardo on Cadastral Plan B of Orange. West is up.

Originally the term was used in cosmology and referred to the east-west axis, which was used as a line of sight when observing the movement of the heavens. The counterpoint is the north-south axis called cardo . The decumanus divided the sky into a day and a night, while the cardo divided the sky into a sunrise and a sunset.

With the surveying device called groma , a coordinate system was created that served as the basis for the other streets and parcels of the city to be created. In gromatic practice, a decumanus maximus (DM) was created, a main axis of orientation that was not based on astronomical, but topographical aspects. Usually the decumanus was laid out where the greatest possible expansion of a city ​​was possible, or where there was already an existing street. The axis orthogonal to this was the cardo maximus (CM). These two main streets were used as a basis for new cities. The decumanus maximus was laid out at a width of 40 Roman feet (twelve meters). That always corresponded to twice the width of the cardo maximus .

The decumanus was also created during the construction of military camps and referred to as prorsi ("facing the enemy").

literature

  • Okko Behrends, Luigi Capogrossi Colognesi (ed.): The Roman art of field measurement. Interdisciplinary contributions on their significance for the history of civilization in Rome. Vandenhoeck and Ruprecht, Göttingen 1992, ISBN 3-525-82480-7
  • Oswald Ashton Wentworth Dilke: The Roman land surveyors. An introduction to the Agrimensores. Hakkert, Amsterdam 1992, ISBN 90-256-1000-5 . Reprint of the 1971 Newton Abbot edition.
  • Ursula Heimberg : Roman land surveying - Limitatio. Small writings on the knowledge of the Roman occupation history of Southwest Germany No. 17. Society for Prehistory and Early History in Württemberg and Hohenzollern / Württembergisches Landesmuseum, Stuttgart 1977
  • Werner Müller : The holy city - Roma quadrata, Jerusalem and the myth of the world navel. Kohlhammer, Stuttgart 1961.
  • Charlotte Schubert : Land and Space in the Roman Republic - the art of sharing. Scientific Book Society, Darmstadt 1996, ISBN 3-534-13189-4