Machinery and techniques
If surveying has undergone major changes in its methods and the results which it achieves, that is mainly due to the advance in the equipment and instruments which the surveyor uses.
This evolution started forty years or so ago with the invention of theodolites which allowed the simultaneous measurement of horizontal and vertical angles. Prior to that innovations had been slow and sporadic but, thereafter progress quickly accelerated.
Thirty years or so ago distance measuring equipment took the place of the measuring chain which surveyors previously used.. Ten years later, tacheometers marked another step forward with their capacity to simultaneously measure horizontally and vertically. At the same time, manual levelling equipment evolved, with electronic levels appearing later at the beginning of the 1990s.
Within the same decade, the use of 3D laser scanners and of course, GPS (one of the uses for which is the guidance, ie remote control, of plant and machinery) began to expand. GPS, an American satellite positioning system, was authorised for civilian use from 1993 which, for the surveying profession, marked the beginning of a radical and continuing change in the techniques which it employs. Satellite Information Systems are another aspect of the same change, since they also supply a global view of the many aspects related to the development of the territory...