Agrimensor

In late Latin the surveyor might be known as a "gromaticus" ("groma" man, from "groma" which was a surveying instrument). However surveyors were more generally known as "agrimensores" (sing. "agrimensor," land surveyors). The "mensor" (plural "Mensores") was a surveyor or measurer, and might well be anything from a corn measurer or a land surveyor to a military surveyor, or an architectural surveyor.

The profession of the ancient surveyor can be variously divided into four major areas of endeavor. However none of these below types are mutually exclusive and those embracing the various skills often used the same instrumentation to arrive at their solutions:

(1) The "agrimensor" or "gromaticus" (land surveyor)was seen to carry out localized surface survey. Within his sphere lay the task of determining a set of street grids for a town, dividing designated land into previously determined size plots, or divining and recording the exact dimensions of a given piece of land. It is this type of Roman surveyor that the "Corpus Agrimensorum" (a set of works compiled as a treatise) which laid down standards for the survey of land was directed to. Land Surveyors were not concerned to any great degree with vertical measurement, concentrating instead upon horizontal measurement.

(2) The "chorographos" or "geographos" (cartographical surveyor) was responsible for the mapping of significant land areas, usually more so than the above mentioned "agrimensor." This class of effort might also relate to the determinations of large portions of the known world, and might further even extend to establishing both latitudes and the line of approximate longitudes using both astronomical and terrestrial methodology

(3) The "mensor" was a military surveyor, and as such was usually occupied in providing information regarding terrain features, as well as other information to his commander like the width of a river for the construction and laying of a pontoon bridge, or the hieght of a city wall to be able to construct necessary tools and machines for the wall's destruction.

(4) The "Mensor or Librator" (engineering surveyor) was used in the area of land survey with the intent to build structures upon the land. The whole array of possible structures fall under this kind of a surveyor from Roads, Aqueducts, Navigable Canals , Harbors, Irrigation and Drainage Channels to Tunnels and Mine Shafts. This type of surveyor needed to be well-trained and experienced in the unique problems of maintaining both vertical (gradient) and horizontal linear direction below the land's surface.

The above categories describe the individual types of surveying experience, but this is not to say that an individual did not have the ability, expertise or experience to act in the auspices of more than one of the above categories. The engineer might also use the same instrumentation in more than one such category to determination the information needed to carry out his task.

References

• M.J.T. Lewis, "Surveying Instruments of Greece and Rome," Cambridge University Press, 2001, ISBN 0521792975;
• K.D. White, "Greek and Roman Technology," Cornell University Press, Ithaca, NY, 1984, ISBN 0801414393;
• L. Sprague de Camp, "The Ancient Engineers," Ballentine Books, NY-NY, 1963, ISBN 0345482875 ;
• O.A.W. Dilke, "The Roman Land Surveyors," Adolf A Hakkert, Amsterdam, 1992, ISBN 9025610005;
• Henry Hodges, "Technology In The Ancient World," Alfred A. Knopf, NY-NY, 1970, ISBN 0140211039.

Originally published in Aquila: http://livinghistoryengineer.com/roman/eagle/09September_Eagle_files/September_Eagle.htm#Engineering%20%96%20Surveyors