A groma was a Roman surveying instrument used to lay out straight lines and right angles, crucial for the construction of roads, buildings, and other infrastructure.
It consisted of a vertical staff with horizontal crosspieces, each with a plumb line hanging from it. Surveyors would align the plumb lines with a distant marker to ensure a perfectly straight line, a method that contributed to the precision and durability of Roman engineering.
Roman engineers used the groma to survey the Via Appia, the first major Roman road that connected Rome to Capua and later extended to Brindisi, enabling rapid military movement and trade.
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