Graffigny, geodesic tower
The exterior of the geodesic tower.
Generally made of brick or stone, oblong in shape, it often resembles a factory chimney. A geodetic marker is embedded in the ground at its center, accessible from the outside through one or more openings at the base of the building.
The height of the structure allows a long plumb line to be run inside, thus protecting it from the wind. This allows the theodolite to be positioned directly above the geodetic marker it sits atop, thus allowing for precise measurements to be taken with other known geodetic points.
