Surveyors tools
Land surveying instruments have a long history. Since the concept of boundaries came into existence, then the pyramids of Egypt, when buildings reached massive proportions, land surveying instruments played a critical role in the location and construction of virtually every plot of land was divided, and every building erected ever since.
American history still acknowledges the great surveyors in our history. George Washington, the leader of the Colonial Army and first president started his career as a land surveyor, starting when he was only 16 years old and lasting several years. The accepted demarcation between the southern and northern states is the border surveyed from 1763 to 1767 by Charles Mason and Jeremiah Dixon still known today as the Mason-Dixon line.
Over the years, a number of various instruments have been invented for measuring distance, direction, vertical and horizontal positions, time and astronomical location. Many have been overtaken by technology which has replaced several different instruments with all-in-one total solutions.
There are still some "old school" surveyors still in business, however to be truly competitive – and often to be in compliance with federal, state and local laws, regulations and ordinances – some form of high-tech laser-based, GPS-enabled, calibrated chronometer, and sometimes astronomically-capable device is not only necessary, but required.
Map tables are rarely used anymore, and the alidade has all but disappeared. The last application for this venerable optical device was the US Forest Service which used a specific type of alidade – a transit used in conjunction with a map table – for locating fires. Today, aerial location is generally much faster and more accurate in locating fires.
Todays most modern technology includes a combination of optics - to roughly orient the device, dual selectable lasers, prodigious amounts of memory to record tens of thousands of measurements, and dozens of jobs simultaneously, response times of calculations in less than a half second and accuracy rapidly approaching the parts per billion range. Affordable units can measure accurately to less than 2 parts per million.