In the 18th and 19th Cs, voyages of exploration, colonial conquests, and the ever more sophisticated needs of cartography stimulated the spread and continuous improvement of geodesic and topographic instruments. The English instrument-maker Jesse Ramsden was the first to introduce, in about 1770, a dividing machine capable of semi-automatic, precise tracing of graduations on the circles of scientific instruments. The device enabled even an unskilled worker to divide an instrument scale in a few minutes and with great precision. The improvement in materials and construction techniques was matched by a major evolution in the design and production of the optical components. Makers such as Ramsden and George Adams made substantial contributions to the spread of the theodolite, which gradually replaced the graphometer. At the same time, new-generation instruments were introduced. In around 1730, Hadley had designed a reflecting octant, from which he would derive the sextant. By the second half of the 18th C., the sextant was progressively replacing the instruments hitherto used to measure the heights of celestial bodies. The Frenchman Borda invented a repeating circle that was used in triangulation work for the precise measurement of the meridian degree—which made possible the exact determination of the meter. The instrument, fitted with two independent telescopes, allowed repeated measurements of an angle in order to obtain a median value with minimal error. The 19th-C. saw optical and mechanical advances in instruments such as theodolites and tacheometers (a kind of theodolite that also allows the measurement of distances). Special models were also developed for various requirements such as surveying for bridge and tunnel construction, plotting rail tracks, and mapping mines.

The best makers of topographic and geodesic instruments were undoubtedly English, French, and German. Italy had to wait until the 1860s for good topographic instruments, with the establishment of the Filotecnica firm (later Filotecnica Salmoiraghi) in Milan, headed by Ignazio Porro. The Officine Galileo in Florence began production in the same period.