Helpful information about the basics of surveying

Surveyors Who Changed the World: Andrew Ellicott

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Andrew Ellicott was an American surveyor who changed the history of the U.S by mapping the territories west of the Appalachians, surveying the boundaries of the District of Columbia and planning the capital, Washington DC. He was undoubtedly one of the most influential surveyors of his time, although he turned down the Government’s offer of the position of Surveyor General – possibly due to their refusal to pay him for one of his most challenging land surveys.

Ellicott was born in Pennsylvania, in 1754. His parents were Quakers with a modest income. Ellicott went to the local Quaker school, where his talent for mechanics and mathematics was noticed. His family bought land on the Patapsco River, opened a milling business and founded the town of Ellicott’s Mills. When the Revolutionary War broke out, Ellicott enlisted and rose to the rank of major.

When the war ended, Ellicott returned to Ellicott’s Mills. In 1784, he was appointed to a group of surveyors tasked with completing the survey of the border between Maryland and Pennsylvania – a project which had been abandoned in 1767, and resulted in the establishment of the boundary which became known as the Mason-Dixon Line.

In 1785, Ellicott and his wife moved to Baltimore, where he taught at the Academy of Baltimore and was elected to the legislature. A year later, he was commissioned for a survey of the western border of Pennsylvania, establishing the Ellicott Line, which later became the principal meridian for the surveys of the Northwest Territory.

Ellicott was appointed to lead a number of other important land surveys, and in 1789, his family moved to Philadelphia. On the recommendation of Benjamin Franklin, who he had met through earlier surveying projects, he secured a role with the new government, carrying out a detailed land survey between Pennsylvania and Lake Eerie, to establish a border between U.S territory and Western New York. During the survey, Ellicott carried out a highly accurate topographical survey of the Niagara River, including Niagara Falls, helping to establish his reputation for excellent standards in surveying.

In 1791, Ellicott worked for commissioners appointed by President George Washington to survey the boundaries of the Territory of Columbia – which would soon become the District of Columbia. Ellicott and his team marked the border with 40 boundary stones, placed one mile apart. Most of the stones are in the same positions today. During this period, Ellicott also worked with Peter Charles L’Enfant on plans for the construction of a new city, Washington DC. Following a series of disagreements with L’Enfant, Ellicott made major changes to the plans, including the removal of several plazas and the straightening of avenues and squares. Ellicott’s plans became the first for the capital city to be widely circulated, but he abandoned the project before its completion.

In 1794, Ellicott was hired to plan the city of Eerie, in Pennsylvania, and he spent the next two years planning a road to the site. Two years later, he became the U.S representative for the survey of the border between the U.S and the Spanish territories of Florida. He worked with Spanish commissioners for the following four years, eventually establishing another ‘Ellicott’s Line’, which remains the border between Florida and Alabama. One of his markers for the boundary has survived, known as Ellicott’s Stone.

Ellicott was not paid for his surveying work, and had to sell some of his possessions to support his family. The Government eventually agreed to give him access to the maps he had created during the survey, at which point he published his Journal of Andrew Ellicott, recalling the Florida survey in detail. When Thomas Jefferson offered Ellicott the position of Surveyor General, he turned it down – possibly due to the problems he had already experienced with the Government – and took a clerk’s job which allowed him to spend more time with his family. Ellicott died of a stroke in 1809, at his home in West Point.

Surveyors Who Changed the World: Jeremiah Dixon

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Jeremiah Dixon was a British surveyor who worked with Charles Mason to determine the famous border between Maryland and Pennsylvania, known as the Mason-Dixon Line. Dixon’s life is not particularly well documented, especially considering his vital role in establishing the cultural border between the North and South of the U.S. He was known to be a Quaker, to wear a long, red coat and to occasionally drink excessively. Despite the mystery surrounding his life, Dixon’s contribution to surveying is undisputed. Many believe his surname even inspired the nickname, Dixie, for the Southern States of the U.S.

Dixon was born in Cockfield, County Durham, in 1733. His father was a wealthy Quaker coal mine owner. As a student, Dixon became interested in astronomy and mathematics. He met astronomers John Bird and Thomas Wright, and mathematician William Emerson, all of whom were well known intellectuals in Durham. It may well have been Bird, a Fellow of the Royal Society, who would put Dixon’s name forward for one of the most famous land surveys to be completed in the U.S.

In 1760, Dixon and Mason were hired to travel to Sumatra by the Royal Astronomical Society, to study the transit of Venus. Although they only made it as far as the Cape of Good Hope, they managed to make a series of valuable observations before returning to England.

Three years later, the heirs of William Penn and Lord Baltimore hired the pair to settle a long-running conflict over the boundary between Maryland and Pennsylvania. It cost Maryland’s Calverts and Pennsylvania’s Penns £3,512/9 to hire them – which they may well have considered a small price to peacefully resolve the dispute.

Dixon and Mason arrived in Philadelphia in November, 1763, and started surveying the northeastern corner of Maryland the following month. Making their way along the parallel of latitude 39°43′17.6″ N, they placed milestones along the 244-mile boundary, each with a ‘P’ on one side and an ‘M’ on the other. The Penn arms of Pennsylvania’s founders and the Calvert arms of Maryland’s founders were branded on every fifth milestone. The project was prevented from finishing when the pair’s Native American guides refused to go any further, having reached the end of their territory and the beginning of another tribe, with whom they were in conflict. The final 36 miles of the boundary were left uncompleted, and they returned to Philadelphia in 1767.

The Mason-Dixon Line is widely regarded as the cultural boundary between the North and South of the U.S – despite the fact that it only separates two states. However, Dixon is unlikely to have ever heard the phrase, ‘Mason-Dixon Line’, since the official report on the survey, published in 1768, didn’t include either of the surveyors’ names. Although it was sometimes used in the decades that followed, its use didn’t become widespread until the Missouri Compromise named ‘Mason and Dixon’s Line’ as a section of the border between slave territory and free territory.

On December 26th, 1767, the pair were discharged as surveyors of the colonial boundary, although they did not return to the UK until a year later. While Mason continued to work for the Royal Society, Dixon sailed to Norway with astronomer William Bayly to observe another transit of Venus. To minimise the chances of bad weather disrupting their measurements, the two separated, with Dixon at Hammerfest Island and Bayly at North Cape.

When the pair returned to England in July, 1769, Dixon continued to work as a surveyor in Durham. He was unmarried when he died in Cockfield January 22, 1779. He was buried at an unmarked grave, at Staindrop’s Quaker cemetery. In 2013, an exhibition titled Jeremiah Dixon: Scientist, Surveyor and Stargazer was opened at the Bowes Museum, in Barnard Castle. A Weardale Railway locomotive was named after Dixon during the same year.

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.



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