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Helpful information about the basics of surveying

The History of Geographic Information System (GIS)

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A geographic information system, or GIS, is a computer system which surveyors and other professionals use to capture, store, assess and present data related to positions on Earth’s surface. Multiple types of data can be displayed by GIS, enabling highly detailed analysis. GIS is used to compare various aspects of locations to gather information about how they relate to each other. A huge variety of data can be compared with GIS, from populations, income and levels of education to lakes, vegetation and soil-types.

Early Days of GIS

One of the original applications of spatial analysis in epidemiology was made in 1832, when the French geographer Charles Picquet represented the 48 districts of Paris with grades of colour which corresponded to the number of cholera deaths per 1,000 inhabitants. In 1854, John Snow achieved one of the first uses of geographic methodology in epidemiology. He made points on a map of where cholera victims lived in London, and identified the cause of an outbreak by connecting areas where there were high numbers of deaths with a neighbouring water source.

During the early 20th century, photozincography was developed, enabling surveyors to divide maps into layers which represented different terrains. This was particularly useful for printing contours, and helped lay the foundations for contemporary GIS.

Canada Leads the Way in GIS Technology

In 1960, the world’s first operational GIS was developed in Ottawa, Canada, by Roger Tomlinson, for the federal Department of Forestry and Rural Development. The Canada Geographic Information System (CGIS) was designed to store, analyse and manipulate data collected on rural Canada by mapping information on soils, agriculture, recreation, forestry and land use at a scale of 1:50,000.

CGIS enabled overlaying, highly accurate measurement and digitalising, and represented a significant improvement on computer mapping. It supported a national coordinate system, with coded lines and an embedded topology, and stored locational information in separate files. Tomlinson became known as the Father of GIS. In 1968, he became the first to use the term ‘geographic information system’ in his paper ‘A Geographic Information System for Regional Planning’.

From Research to Business

Two major public domain GIS systems, MOSS and GRASS GIS, were in development by the 1970s. By the early Eighties, several computing firms had incorporated CGIS features and emerged as commercial vendors of GIS.

The first desktop GIS product, Mapping Display and Analysis System, was released in 1986. In 1990, it was renamed MapInfo for Windows, on Microsoft Windows, starting the process of moving GIS into the business environment.

Users had started viewing GIS data on the Internet by the end of the 20th century. Several free, open-source GIS packages now run on various operating systems and can be customised for specific tasks. An increasing number of geospatial data and mapping applications are available online

The History of Jesse Ramsden’s Surveying Instruments

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Jesse Ramsden was an English mathematician and instrument-maker who created several ground-breaking instruments in the 18th century. Ramsden’s sextants, dividing engines and theodolites played an important role in the development of surveying, not only in the UK but around the world.

Early Life & Introduction to Instrument-Making
Jesse Ramsden was born near Halifax, Yorkshire, on October 6th, 1735. He went to school until 1747, when he was sent to live with his uncle, in North Riding, where he studied mathematics. Ramsden spent four years working in cloth making before becoming an apprentice for a mathematical instrument-maker. His talent was obvious, and within just four years, he had opened his own instrument-making shop in London. Ramsden quickly gained a reputation as one of England’s best manufacturers of mathematical, navigational, astronomical and surveying instruments. He went on to produce instruments for George III, make significant improvements to the surveyor’s theodolite and transit, and invent the dividing engine – which enabled him to manufacture remarkably accurate surveying instrument scales. His innovative sextant was used by Captain Cook during his exploration of the Great Southern Oceans, and his famous Great Theodolites were vital in a number of pioneering land surveys.

Rods & Chains
Gunter’s chains were generally used for surveying in the 18th century, but they were considered too inaccurate for Britain’s first high-precision survey, the Anglo-French Survey, for which Ramsden was commissioned to create a chain of 100 one-foot links. He was also asked to make three 20-foot wooden rods for the project. The rods proved ineffective due to their length being affected by humidity, but Ramsden’s chains were highly accurate, and were used in numerous baseline surveys over the following 30 years.

Zenith Telescope
Ramsden’s portable Zenith Telescope was designed to bring observatory-precision to fieldwork. It was manufactured in 1802 to determine the latitude of various stations of the Principal Triangulation of Great Britain. The telescope was mounted on an 8ft inner frame, and its outer frame was around 12ft tall. It could only be used for observations within a few degrees of the zenith to avoid refraction-related inaccuracies.

Ramsden’s Great Theodolites
Ramsden’s huge theodolites enabled surveyors to take measurements with an impressive degree of accuracy. Eight instruments were manufactured for a series of surveys in the UK, Switzerland and India. Three of the Great Theodolites were constructed by Ramsden, and another two were built using his instructions, by his son-in-law Mathew Berge. Two more were made by the firm Troughton and Simms, and another by William Cary, an English instrument-maker who trained under Ramsden.

Three years after General William Roy commissioned Ramsden to create new instruments for the Anglo-French Survey, his Great Theodolite was delivered (following a delay which was blamed on Ramsden’s perfectionism and tardiness, and a series of accidents in his workshop). The instrument was paid for by the Crown and immediately presented to the Royal Society.

Death & Legacy
Ramsden was elected to the Royal Society in 1786, and was awarded the Copley Medal in 1795. He died in on November 5th, 1800, in Brighton. A Moon crater was named in honour of his pioneering work. Ramsden’s creations have withstood the test of time, and instruments based on his designs are still widely used in surveying today.

The History of the Dividing Engine

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The invention of the circular dividing engine was an important moment for surveying. The measurement inscriptions on instruments such as the compass had previously been made by hand, which meant their accuracy varied considerably. The dividing engine eliminated the problem of human error and paved the way for instruments with a consistently high degree of accuracy to be produced.


Exactly when and by whom the first dividing engine was made remains unclear, but one of its first creators was undoubtedly clockmaker Henry Hindley, in around 1739. His instrument was based on a gear-cutting machine for clockworks, and used a worm-gear and toothed index gear-plate to operate the mechanism.



Sometime between 1765 and 1768, Duc de Chaulnes produced a pair of dividing engines for dividing circular arcs and linear scales, which were also inspired by clockmaking. Chaulnes’ goal was to improve the accuracy of instruments by removing the danger of human error wherever possible.

In 1773, Jesse Ramsden produced a dividing engine with a screw-cutting lathe which was a significant improvement on previous designs. Ramsden received funding for his dividing engine from the Board of Longitude, on the condition that his design would not be patented, and he would teach others to create their own.

Following the invention of the dividing engine, the UK had a near-monopoly on the precision instrument industry, as other countries failed to produce anything as accurate as the instruments based on Ramsden’s creation. In the early 1800s, American surveying instrument specialist William J Young created a larger dividing engine, which he claimed allowed an even greater degree of precision. He modified his dividing engine so it could be operated automatically. Later, he produced a circular dividing engine with a 48-inch radius, which was used in the graduation of scales for engineers’ transits and other instruments.

The instruments produced with Young’s automatic dividing engine played a key role in the exploration and colonisation of the American West. The dividing engine made it possible to produce more accurate surveyors’ compasses, and a number of other valuable instruments, including the railroad compass, which was widely used as railway lines were laid across the U.S. Later, the surveyor’s transit was developed by replacing its sighting bars with a telescope which could be revolved on its horizontal axis. Young’s transit achieved widespread popularity among surveyors shortly after the launch of its commercial production, in the mid-1800s.

Christian Louis Berger also played an important role in the development of the dividing engine. In 1871, after a number of years working with some of the world’s best instrument makers, he and George L Buff established Buff and Berger, producing instruments for surveying, engineering, mining and science. The pair developed a reputation for producing high-quality precision instruments, until the firm was dissolved in 1898, following a dispute. After acquiring the company’s assets, Berger and his sons moved the business to Roxbury, Massachusetts, where they produced instruments for geodetic, civil, geological and petroleum surveyors internationally. With their highly accurate dividing engines, this was perhaps the company’s most productive period, and the company remained influential until it was eventually sold, in 1948.

 

The History of GPS

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The Global Positioning System, or GPS, is a network of satellites which transmit signals to receivers on the ground while they orbit Earth. The signals have a time code and geographical date which enables users to identify their location with a high degree of accuracy. Since GPS was made available for non-military purposes, it has become an essential surveying tool. GPS was initially created as an intelligence and military tool during the Cold War. On October 4, 1957, MIT scientists studying the Russian satellite known as Sputnik noticed that its radio signal grew as it approached and diminished as it got further away – a phenomenon known as the Doppler Effect.

The scientists’ observations of Sputnik inspired them to track satellites from the ground by measuring the frequency of their radio signals, and track the location of receivers on the ground by measuring their distance from the satellites. This is the foundation of the principle behind the GPS receivers used in cars, phones and various industries, including surveying. In 1959, the U.S Navy created TRANSIT, a satellite navigation system which was designed to track submarines, initially with six satellites and later, 10. Although the system was slow compared to today’s systems, TRANSIT paved the way for the development for GPS. In 1963, the Aerospace Corporation carried out a study into the possibility of creating a system of space satellites which would send continuous signals to receivers on the ground. The study, which was completed for the U.S Military, laid the conceptual foundations for today’s GPS, with satellites capable of tracking fast-moving vehicles on the ground and in the air, and generating highly accurate location coordinates by recording the transmission times of signals sent from space satellites.

The first test satellite of the proposed 24-satellite system NAVSTAR was launched by the Military in 1974, following 11 years of work on the project. From 1978 to 1985, 11 NAVSTAR test satellites were launched, with on-board atomic clocks to precisely measure transmission times. In 1989, following years of intensive testing, the Air Force released the first fully functioning GPS satellite into space, using the Delta II Rocket.

The Magellan NAV 1000, which was claimed to be the first hand-held navigation device using GPS, went on the market in 1989. But a year later, the U.S Defence Department intentionally lowered the accuracy of GPS, amid concerns that adversary nations may find a way of using it to their advantage.

In 1995, the last of 27 GPS satellites was released into space, three of which were spares to replace any of the 24 active satellites, should they develop a fault. The 3,000-4,0000-pound satellites circled Earth twice per day.

Plans for the transmission of two additional GPS for non-military use were announced in 1998, and shortly afterwards, in 2000, the Defence Department’s intentional diminishment of the system’s accuracy was ended – and GPS became ten times more accurate. Before long, GPS was an important tool in a range of industries, from fishing to surveying. GPS technology quickly became cheaper and more compact, and an array of products, such as vehicle navigation devices, were soon on the market.

The History of the Spirit Level

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Spirit levels are used in surveying, carpentry, construction and other professions to identify whether a surface is horizontal or vertical. In their early days, they included curved, glass vials with continuous inner-diameter at each viewing point. The vials were partially filled with liquid – usually alcohol or a coloured sprit – leaving a bubble in the tube. The vials’ subtle upward curve caused the bubble to rest in the middle, at the highest point. The bubble reacted to any inclination by moving away from the center position. 


Alcohols such as ethanol are often used in spirit levels, due to their low surface tension and viscosity, which allows the bubble to move quickly through the tube and settle accurately, with minimal interference.

The bull’s eye level is a circular, flat-bottomed device with liquid underneath a convex glass face, with a circle at the center. Unlike a standard level, a bull’s eye level can be used to level a surface across a plane – rather than only in the direction of the tube.

The sprit level was invented by Melchisedech Thevenot, a wealthy amateur scientist and royal librarian to Louis XIV of France. Examination of correspondence between Thevenot and scientist Christiaan Huygens has revealed that the spirit level was invented at some point before February 2, 1661. Thevenot quickly released a description of his creation to others around Europe, including Vincenzo Viviani, in Florence, and Robert Hooke, in London. Exactly when use of the spirit level in land surveys and other projects became widespread remains unclear, with some arguing that they did not gain popularity until the 18th century, since it is from this period that the oldest surviving examples date. However, there are records of the Academie Royale des Sciences being advised to take “levels of the Thevenot type” on their expedition to Madagascar, in 1666.

The modern level with a single vial was invented by Henry Ziemann, in the 1920s and, in 1939, William B. Fell created the Fell All-Way precision level, in Rockford, Illinois. This bull’s eye level could be positioned on a machine bed and display tilt on the x-y axes, making it unnecessary to rotate the level 90 degrees. Compared to previous designs, Fell’s level was remarkably accurate, and set a new standard of .0005 inches per foot resolution.

Production of the Fell All-Way precision level ceased in around 1970, and was resumed in the ‘80s by Thomas Butler Technology, in Rockford, Illinois, before finally ending in the ‘90s. The spirit level remains an important tool for surveying and various other industries, and has been incorporated into the design of a number of other tools. The dumpy level, which is used to measure height differences over larger distances, often features an inbuilt spirit level. It was invented in 1832, by English civil engineer, William Gravatt. Commissioned to examine a railway route from London to Dover, he devised the dumpy level as a more mobile and easier-to-use alternative to the Y level.



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