The instructions for this theodolite are described in the book that forms an integral part of the instrument itself. The compass mounted on the tablet is used for topographic measurement in the same manner as an ordinary surveying compass. But it also serves to measure angles for the construction of fortifications with a regular or irregular perimeter. The half-disk with the altimeter scale, plumb bob, and diopter is used to measure heights, distances, and depths, as well as for land leveling and aqueduct construction. The two components—the compass and the altimeter scale—are used together for perspective drawing. This requires a complex conversion of angular values into linear measures. Such methods attest to the deep affinities that existed in the early modern age between artistic and mathematical pursuits.