Generally lasers and global positioning system use for setting up building corners and delineating building perimeters so foundation work could start used to rely on string and steel tape measures, and were calculated from measurements drawn from the property boundary lines. Lasers and GPS have made that work much more accurate and much faster. Heavy equipment used to rely on the operators to accurately read grade stakes, and set equipment blades and buckets at the right angle to get cut and fill operations and trenches right. Laser- and GPS-equipped machines now make fine adjustments to the machine's settings so the work is done more accurately the first time.
Global Positioning System (GPS)
The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information, anywhere on or near the Earth where there is an unobstructed line of sight to GPS satellites. GPS basic positioning is done by triangulation, calculating the distance between the receiver and a minimum of four satellites.  GPS combines high accuracy of the result with the possibility of surveying continuously in all weather conditions and the ease of equipment installation allows a high degree of automation and can obtain results in nearly real time.  The system provides critical capabilities to military, civil and commercial users around the world. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver. A GPS receiver calculates its position by precisely timing the signals sent by the GPS satellites high above the Earth. Each satellite continually transmits messages which include
* The time the message was transmitted
* Precise orbital information (the ephemeris)
* The general system health and rough orbits of all GPS satellites (the almanac).
The receiver utilizes the messages it receives to determine the transit time of each message...