Museo della centuriazione romana (Borgoricco) 02

The ''groma'' or ''gruma'' was a

Roman Roman or Romans most often refers to: * Rome, the capital city of Italy * Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a lett ...

surveying instrument. 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. The same name was given to: * the center of any new

military camp A military camp or bivouac is a semi-permanent military base, for the lodging of an army. Camps are erected when a military force travels away from a major installation or fort during training or operations, and often have the form of large cam ...

, i.e. the point from which was traced the regular grid by using the ''groma'' instrument * the center of a new town, from which the

gromatici ''Gromatici'' (from Latin '' groma'' or ''gruma'', a surveyor's pole) or ''agrimensores'' was the name for land surveyors amongst the ancient Romans. The "gromatic writers" were technical writers who codified their techniques of surveying, most ...

(surveyors) began to lay out

cardo A cardo (plural ''cardines'') was a north–south street in Ancient Roman cities and military camps as an integral component of city planning. The cardo maximus, or most often the ''cardo'', was the main or central north–south-oriented street. ...

and decumanus grid, with a plough and a pair of oxen The groma surveying instrument may have originated in

Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders wi ...

before the 4th century BC. Subsequently, it was brought to Rome by the

Etruscans The Etruscan civilization () was developed by a people of Etruria in ancient Italy with a common language and culture who formed a federation of city-states. After conquering adjacent lands, its territory covered, at its greatest extent, roug ...

and named cranema or ferramentum.

Notes

External links

BBC: h2g2: The Groma: The Tool That Built An Empire

University of Arizona – Archaeological Mapping Lab
{{Authority control Surveying instruments Historical scientific instruments