Survey point
Around 1800 Dunnose was taken as a base point for a triangulation of Great Britain, in which Captain William Mudge measured a section of the meridional arc running up into Yorkshire. The triangulation was conducted in 1801 and 1802. The positions of twenty three points between Dunnose [lower-alpha 1] and Beacon Hill, Clifton, near Doncaster, were determined, and the closest possible measurements were made of the distances between the points and the direction from one point to another. Doubts were cast on the accuracy of the measurements in 1812, when Joseph Rodriguez pointed out that, if they were accurate, the length of a degree of longitude did not vary with latitude as it should if the earth were flattened at the poles. The Retriangulation of Great Britain that began in 1935 again took Dunnose as a base point. Dunnose also was the origin (meridian) of the 6 inch and 1:2500 Ordnance Survey maps for the central group of English counties: they were Derbyshire, Nottinghamshire, Lincolnshire, Staffordshire, Warwickshire, Worcestershire, Leicestershire, Rutlandshire, Northamptonshire, Gloucestershire, Oxfordshire, Buckinghamshire, Wiltshire, Berkshire, Hampshire and the Isle of Wight. [8]
A Kater's pendulum is a reversible free swinging pendulum invented by British physicist and army captain Henry Kater in 1817 for use as a gravimeter instrument to measure the local acceleration of gravity. Its advantage is that, unlike previous pendulum gravimeters, the pendulum's centre of gravity and center of oscillation do not have to be determined, allowing a greater accuracy. For about a century, until the 1930s, Kater's pendulum and its various refinements remained the standard method for measuring the strength of the Earth's gravity during geodetic surveys. It is now used only for demonstrating pendulum principles.
Scafell Pike is a mountain in the Lake District region of Cumbria, England. It has an elevation of 978 metres (3,209 ft) above sea level, making it the highest and the most prominent mountain in England. The mountain is part of the Scafell massif, an inactive volcano, and is one of the Southern Fells.
Shanklin is a seaside resort town and civil parish on the Isle of Wight, England, located on Sandown Bay. Shanklin is the southernmost of three settlements which occupy the bay, and is close to Lake Sandown. The sandy beach, its Old Village and a wooded ravine, Shanklin Chine, are its main attractions. The esplanade along the beach is occupied by hotels and restaurants for the most part, and is one of the most tourist-oriented parts of the town. The other is the Old Village, at the top of Shanklin Chine. Together with Lake and Sandown to the north, Shanklin forms a built up area of around 25,000 inhabitants.
Dent is a small fell on the fringe of the English Lake District near the towns of Cleator Moor and Egremont. Sometimes known as Long Barrow, it is traditionally the first fell encountered by hikers following Wainwright's Coast to Coast Walk. It slopes from the westerly point of the Lake District National Park.
The Retriangulation of Great Britain was a triangulation project carried out between 1935 and 1962 that sought to improve the accuracy of maps of Great Britain. Data gathered from the retriangulation replaced data gathered during the Principal Triangulation of Great Britain, which had been performed between 1783 and 1851.
The Ramsden surveying instruments are those constructed by Jesse Ramsden and used in high precision geodetic surveys carried out in the period 1784 to 1853. This includes the five great theodolites—great in name, great in size and great in accuracy—used in surveys of Britain and other parts of the world. Ramsden also provided the equipment used in the measurement of the many base lines of these surveys and also the zenith telescope used in latitude determinations.
The Principal Triangulation of Britain was the first high-precision triangulation survey of the whole of Great Britain and Ireland, carried out between 1791 and 1853 under the auspices of the Board of Ordnance. The aim of the survey was to establish precise geographical coordinates of almost 300 significant landmarks which could be used as the fixed points of local topographic surveys from which maps could be drawn. In addition there was a purely scientific aim in providing precise data for geodetic calculations such as the determination of the length of meridian arcs and the figure of the Earth. Such a survey had been proposed by William Roy (1726–1790) on his completion of the Anglo-French Survey but it was only after his death that the Board of Ordnance initiated the trigonometric survey, motivated by military considerations in a time of a threatened French invasion. Most of the work was carried out under the direction of Isaac Dalby, William Mudge and Thomas Frederick Colby, but the final synthesis and report (1858) was the work of Alexander Ross Clarke. The survey stood the test of time for a century, until the Retriangulation of Great Britain between 1935 and 1962.
The Great Trigonometrical Survey of India was a project that aimed to survey the entire Indian subcontinent with scientific precision. It was begun in 1802 by the British infantry officer William Lambton, under the auspices of the East India Company. Under the leadership of his successor, George Everest, the project was made the responsibility of the Survey of India. Everest was succeeded by Andrew Scott Waugh, and after 1861, the project was led by James Walker, who oversaw its completion in 1871.
Thomas Frederick Colby FRS FRSE FGS FRGS, was a British major-general and director of the Ordnance Survey (OS). A Fellow of the Royal Astronomical Society and Royal Society, Colby was one of the leading geographers of his time.
Col Alexander Ross Clarke FRS FRSE (1828–1914) was a British geodesist, primarily remembered for his calculation of the Principal Triangulation of Britain (1858), the calculation of the Figure of the Earth and one of the most important text books of Geodesy (1880). He was an officer of the Royal Engineers employed on the Ordnance Survey.
HMSEurydice was a 26-gun Royal Navy corvette which was the victim of one of Britain's worst peacetime naval disasters when she sank in 1878.
Admiral ZacharyMudge was an officer in the British Royal Navy, best known for serving in the historic Vancouver Expedition.
TSMV Shanklin was a passenger ferry that operated between Portsmouth and the Isle of Wight between 1951 and 1980. Renamed Prince Ivanhoe she went on to become a pleasure cruiser in the Bristol Channel but in 1981 sank off the Welsh coast on her first season.
The Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose, which was to map Scotland in the wake of the Jacobite rising of 1745. There was also a more general and nationwide need in light of the potential threat of invasion during the Napoleonic Wars. Since 1 April 2015, the Ordnance Survey has operated as Ordnance Survey Ltd, a government-owned company, 100% in public ownership. The Ordnance Survey Board remains accountable to the Secretary of State for Science, Innovation and Technology. It was also a member of the Public Data Group.
Colonel Robert Kearsley Dawson was an English surveyor and cartographer of the Corps of Royal Engineers.
William Mudge (1762–1820) was an English artillery officer and surveyor, born in Plymouth, an important figure in the work of the Ordnance Survey.
Richard Zachariah Mudge (1790–1854) was an English officer of the Royal Engineers, known as a surveyor.
The Anglo-French Survey (1784–1790) was the geodetic survey to measure the relative position of the Royal Greenwich Observatory and the Paris Observatory via triangulation. The English operations, executed by William Roy, consisted of the measurements of bases at Hounslow Heath (1784) and Romney Marsh (1787), the measurements of the angles of the triangles (1787–1788) and finally the calculation of all the triangles (1788–1790). The survey is very significant as the first precise survey within Britain, and the forerunner of the work of the Ordnance Survey which was founded in 1791, one year after Roy's death.
Isaac Dalby was an English mathematician, surveyor and teacher. He was involved in the Principal Triangulation of Great Britain, the first high-precision trigonometric survey of Great Britain.
James Gardner was an English surveyor, lithographer, cartographer, engraver and publisher who played an active role in the trigonometrical survey of Great Britain. His career spanned the years 1808 to 1840.
