| 词条 | Groma surveying |
| 释义 |
The Groma or gruma was a Roman surveying instrument.[1] It comprised a vertical staff with horizontal cross-pieces mounted at right angles on a bracket. Each cross piece had a plumb line hanging vertically at each end. It was used to survey straight lines and right angles, thence squares or rectangles. They were stabilized on the high ground, and pointed in the direction it was going to be used. The helper would step back 100 steps and place a pole. The surveyor would tell him where to move the pole and the helper would set it down.[2] The same name was given to:
The groma surveying instrument may have originated in Mesopotamia or Greece before the 4th century BC. Subsequently, it was brought to Rome by the Etruscans and named cranema or ferramentum.[3][4] Notes1. ^Cesare Rossi, Marco Ceccarelli, Michela Cigola, The groma, the surveyor's cross and the chorobates. In-depth notes on the design of the old instruments and their use. La Groma, lo Squadro agrimensorio e il corobate. Note di approfondimento su progettazione e funzionalità di antiche strumentazioni, in Disegnare Idee Immagini, anno XXII n. 42/2011; pp. 22-33. {{ISBN|978-88-492-2248-7}}, ISSN IT 1123-924 2. ^{{cite book|last=Lewis|first=M. J. T.|title=Surveying Instruments of Greece and Rome|url=https://books.google.com/books?id=1Izau5_ihmsC|accessdate=29 June 2014|date=2001-04-23|publisher=McGraw Hill Professional|isbn=9781139430357|page=120}} 3. ^{{cite book|last1=Yan|first1=Hong-Sen|last2=Ceccarelli|first2=Marco|title=International Symposium on History of Machines and Mechanisms: Proceedings of HMM 2008|url=https://books.google.com/books?id=Dkq6_mdW43IC&pg=PR5|accessdate=28 June 2014|date=2009-01-11|publisher=Springer|isbn=9781402094859|page=107}} 4. ^{{cite book|title=Surveying Instruments of Greece and Rome|page=120|year=2001|publisher=Cambridge University Press|last1=Lewis|first1=M. J. T.|isbn=9780521792974}} External links{{commons category|Groma}}
2 : Ancient Roman architecture|Surveying instruments |
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