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Surveying or land surveying is the technique, profession, art, and science of determining the
terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
two-dimensional or three-dimensional positions of
point Point or points may refer to: Places * Point, Lewis, a peninsula in the Outer Hebrides, Scotland * Point, Texas, a city in Rains County, Texas, United States * Point, the NE tip and a ferry terminal of Lismore, Inner Hebrides, Scotland * Point ...
s and the
distance Distance is a numerical or occasionally qualitative measurement of how far apart objects or points are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two counties over"). ...
s and
angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two ...
s between them. A land surveying professional is called a land surveyor. These points are usually on the surface of the Earth, and they are often used to establish maps and boundaries for
ownership Ownership is the state or fact of legal possession and control over property, which may be any asset, tangible or intangible. Ownership can involve multiple rights, collectively referred to as title, which may be separated and held by different ...
, locations, such as the designed positions of structural components for construction or the surface location of subsurface features, or other purposes required by government or civil law, such as property sales. Surveyors work with elements of
geodesy Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...
,
geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is c ...
,
trigonometry Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. T ...
,
regression analysis In statistical modeling, regression analysis is a set of statistical processes for estimating the relationships between a dependent variable (often called the 'outcome' or 'response' variable, or a 'label' in machine learning parlance) and one ...
,
physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
, engineering,
metrology Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in Fran ...
,
programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...
s, and the law. They use equipment, such as
total station A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure b ...
s, robotic total stations,
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...
s,
GNSS A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pre ...
receivers,
retroreflector A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, ...
s,
3D scanner 3D scanning is the process of analyzing a real-world object or environment to collect data on its shape and possibly its appearance (e.g. color). The collected data can then be used to construct digital 3D modelling, 3D models. A 3D scanner can ...
s, LiDAR sensors, radios,
inclinometer An inclinometer or clinometer is an measuring instrument, instrument used for measuring angles of slope, elevation, or depression (geology), depression of an object with respect to gravity's direction. It is also known as a ''tilt indicator'', ' ...
, handheld tablets, optical and digital
level Level or levels may refer to: Engineering *Level (instrument), a device used to measure true horizontal or relative heights *Spirit level, an instrument designed to indicate whether a surface is horizontal or vertical *Canal pound or level *Regr ...
s, subsurface locators, drones,
GIS A geographic information system (GIS) is a type of database containing Geographic data and information, geographic data (that is, descriptions of phenomena for which location is relevant), combined with Geographic information system software, sof ...
, and surveying software. Surveying has been an element in the development of the human environment since the beginning of
recorded history Recorded history or written history describes the historical events that have been recorded in a written form or other documented communication which are subsequently evaluated by historians using the historical method. For broader world hist ...
. The planning and execution of most forms of construction require it. It is also used in transport, communications, mapping, and the definition of legal boundaries for land ownership, and is an important tool for research in many other scientific disciplines.


Definition

The
International Federation of Surveyors International Federation of Surveyors (abbreviated FIG, after the french: Fédération Internationale des Géomètres) is the UN-recognized global organization for the profession of surveying and related disciplines. It was established in 1878,
defines the function of surveying as follows:
A surveyor is a professional person with the academic qualifications and technical expertise to conduct one, or more, of the following activities; * to determine, measure and represent land, three-dimensional objects, point-fields and trajectories; * to assemble and interpret land and geographically related information, * to use that information for the planning and efficient administration of the land, the sea and any structures thereon; and, * to conduct research into the above practices and to develop them.


History


Ancient history

Surveying has occurred since humans built the first large structures. In ancient Egypt, a
rope stretcher In ancient Egypt, a rope stretcher (or harpedonaptai) was a surveyor who measured real property demarcations and foundations using knotted cords, stretched so the rope did not sag. The practice is depicted in tomb paintings of the Theban Necropol ...
would use simple geometry to re-establish boundaries after the annual floods of the
Nile River The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest rive ...
. The almost perfect squareness and north–south orientation of the
Great Pyramid of Giza The Great Pyramid of Giza is the biggest Egyptian pyramid and the tomb of Fourth Dynasty pharaoh Khufu. Built in the early 26th century BC during a period of around 27 years, the pyramid is the oldest of the Seven Wonders of the Ancient World, ...
, built c. 2700 BC, affirm the Egyptians' command of surveying. The '' groma'' instrument originated in
Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the F ...
(early 1st millennium BC). The prehistoric monument at
Stonehenge Stonehenge is a prehistoric monument on Salisbury Plain in Wiltshire, England, west of Amesbury. It consists of an outer ring of vertical sarsen standing stones, each around high, wide, and weighing around 25 tons, topped by connectin ...
(c. 2500 BC) was set out by prehistoric surveyors using peg and rope geometry. The mathematician
Liu Hui Liu Hui () was a Chinese mathematician who published a commentary in 263 CE on ''Jiu Zhang Suan Shu (The Nine Chapters on the Mathematical Art).'' He was a descendant of the Marquis of Zixiang of the Eastern Han dynasty and lived in the state o ...
described ways of measuring distant objects in his work ''
Haidao Suanjing ''Haidao Suanjing'' (; ''The Sea Island Mathematical Manual'') was written by the Chinese mathematician Liu Hui of the Three Kingdoms era (220–280) as an extension of chapter 9 of ''The Nine Chapters on the Mathematical Art''. L. van. He ...
'' or ''The Sea Island Mathematical Manual'', published in 263 AD. The Romans recognized land surveying as a profession. They established the basic measurements under which the Roman Empire was divided, such as a tax register of conquered lands (300 AD). Roman surveyors were known as ''
Gromatici ''Gromatici'' (from Latin '' groma'' or ''gruma'', a surveyor's pole) or ''agrimensores'' was the name for land surveyors amongst the ancient Romans. The "gromatic writers" were technical writers who codified their techniques of surveying, most ...
''. In medieval Europe,
beating the bounds Beating the bounds or perambulating the bounds is an ancient custom still observed in parts of England, Wales, and the New England region of the United States, which traditionally involved swatting local landmarks with branches to maintain a shared ...
maintained the boundaries of a village or parish. This was the practice of gathering a group of residents and walking around the parish or village to establish a communal memory of the boundaries. Young boys were included to ensure the memory lasted as long as possible. In England,
William the Conqueror William I; ang, WillelmI (Bates ''William the Conqueror'' p. 33– 9 September 1087), usually known as William the Conqueror and sometimes William the Bastard, was the first House of Normandy, Norman List of English monarchs#House of Norman ...
commissioned the
Domesday Book Domesday Book () – the Middle English spelling of "Doomsday Book" – is a manuscript record of the "Great Survey" of much of England and parts of Wales completed in 1086 by order of King William I, known as William the Conqueror. The manusc ...
in 1086. It recorded the names of all the land owners, the area of land they owned, the quality of the land, and specific information of the area's content and inhabitants. It did not include maps showing exact locations.


Modern era

Abel Foullon Abel Foullon (1513–1563 or 1565, in France) was an author, director of the Mint (coin), Mint for Henry II of France and also an engineer to the king of France after Leonardo da Vinci. His Holometer is an instrument for making of angular mea ...
described a
plane table A plane table (plain table prior to 1830) is a device used in surveying site mapping, exploration mapping, coastal navigation mapping, and related disciplines to provide a solid and level surface on which to make field drawings, charts and maps. ...
in 1551, but it is thought that the instrument was in use earlier as his description is of a developed instrument.
Gunter's chain Gunter's chain (also known as Gunter’s measurement) is a distance measuring device used for surveying. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter (1581–1626). It enabled plots of land to be a ...
was introduced in 1620 by English mathematician
Edmund Gunter Edmund Gunter (158110 December 1626), was an English clergyman, mathematician, geometer and astronomer of Welsh descent. He is best remembered for his mathematical contributions which include the invention of the Gunter's chain, the Gunter's q ...
. It enabled plots of land to be accurately surveyed and plotted for legal and commercial purposes. Leonard Digges described a
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...
that measured horizontal angles in his book ''A geometric practice named Pantometria'' (1571). Joshua Habermel ( Erasmus Habermehl) created a theodolite with a compass and tripod in 1576. Johnathon Sission was the first to incorporate a telescope on a theodolite in 1725.Turner, Gerard L'E. ''Nineteenth Century Scientific Instruments'', Sotheby Publications, 1983, In the 18th century, modern techniques and instruments for surveying began to be used.
Jesse Ramsden Jesse Ramsden FRS FRSE (6 October 1735 – 5 November 1800) was a British mathematician, astronomical and scientific instrument maker. His reputation was built on the engraving and design of dividing engines which allowed high accuracy measureme ...
introduced the first precision
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...
in 1787. It was an instrument for measuring
angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two ...
s in the horizontal and vertical planes. He created his
great theodolite 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 accura ...
using an accurate
dividing engine A dividing engine is a device employed to mark graduations on measuring instruments to allow for reading smaller measurements than can be allowed by directly engraving them. The well-known vernier scale and micrometer screw-gauge are classic e ...
of his own design. Ramsden's theodolite represented a great step forward in the instrument's accuracy.
William Gascoigne Sir William Gascoigne (c. 135017 December 1419) was Chief Justice of England during the reign of King Henry IV. Life and work Gascoigne (alternatively spelled Gascoyne) was a descendant of an ancient Yorkshire family. He was born in Gawthor ...
invented an instrument that used a
telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
with an installed
crosshair A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, ...
as a target device, in 1640.
James Watt James Watt (; 30 January 1736 (19 January 1736 OS) – 25 August 1819) was a Scottish inventor, mechanical engineer, and chemist who improved on Thomas Newcomen's 1712 Newcomen steam engine with his Watt steam engine in 1776, which was fun ...
developed an optical meter for the measuring of distance in 1771; it measured the
parallactic angle In spherical astronomy, the parallactic angle is the angle between the great circle through a celestial object and the zenith, and the hour circle of the object. It is usually denoted ''q''. In the triangle zenith—object—celestial pole, the par ...
from which the distance to a point could be deduced. Dutch mathematician
Willebrord Snellius Willebrord Snellius (born Willebrord Snel van Royen) (13 June 158030 October 1626) was a Dutch astronomer and mathematician, Snell. His name is usually associated with the law of refraction of light known as Snell's law. The lunar crater Sn ...
(a.k.a. Snel van Royen) introduced the modern systematic use of
triangulation In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle me ...
. In 1615 he surveyed the distance from
Alkmaar Alkmaar () is a city and municipality in the Netherlands, located in the province of North Holland, about 30 km north of Amsterdam. Alkmaar is well known for its traditional cheese market. For tourists, it is a popular cultural destination. The ...
to
Breda Breda () is a city and municipality in the southern part of the Netherlands, located in the province of North Brabant. The name derived from ''brede Aa'' ('wide Aa' or 'broad Aa') and refers to the confluence of the rivers Mark and Aa. Breda has ...
, approximately . He underestimated this distance by 3.5%. The survey was a chain of quadrangles containing 33 triangles in all. Snell showed how planar formulae could be corrected to allow for the curvature of the earth. He also showed how to resect, or calculate, the position of a point inside a triangle using the angles cast between the vertices at the unknown point. These could be measured more accurately than bearings of the vertices, which depended on a compass. His work established the idea of surveying a primary network of control points, and locating subsidiary points inside the primary network later. Between 1733 and 1740,
Jacques Cassini Jacques Cassini (18 February 1677 – 16 April 1756) was a French astronomer, son of the famous Italian astronomer Giovanni Domenico Cassini. Cassini was born at the Paris Observatory. Admitted at the age of seventeen to membership of the French ...
and his son César undertook the first triangulation of France. They included a re-surveying of the
meridian arc In geodesy and navigation, a meridian arc is the curve between two points on the Earth's surface having the same longitude. The term may refer either to a segment of the meridian, or to its length. The purpose of measuring meridian arcs is to de ...
, leading to the publication in 1745 of the first map of France constructed on rigorous principles. By this time triangulation methods were well established for local map-making. It was only towards the end of the 18th century that detailed triangulation network surveys mapped whole countries. In 1784, a team from General
William Roy Major-General William Roy (4 May 17261 July 1790) was a Scottish military engineer, surveyor, and antiquarian. He was an innovator who applied new scientific discoveries and newly emerging technologies to the accurate geodetic mapping of Gr ...
's
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of Great Britain began the
Principal Triangulation of Britain The Principal Triangulation of Britain was the first high-precision triangulation survey of the whole of Great Britain (including Ireland), carried out between 1791 and 1853 under the auspices of the Board of Ordnance. The aim of the survey was ...
. The first Ramsden theodolite was built for this survey. The survey was finally completed in 1853. The
Great Trigonometric Survey The Great Trigonometrical Survey 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.Gil ...
of India began in 1801. The Indian survey had an enormous scientific impact. It was responsible for one of the first accurate measurements of a section of an arc of longitude, and for measurements of the geodesic anomaly. It named and mapped
Mount Everest Mount Everest (; Tibetan: ''Chomolungma'' ; ) is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border runs across its summit point. Its elevation (snow heig ...
and the other Himalayan peaks. Surveying became a professional occupation in high demand at the turn of the 19th century with the onset of the
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
. The profession developed more accurate instruments to aid its work. Industrial infrastructure projects used surveyors to lay out
canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow un ...
s, roads and rail. In the US, the
Land Ordinance of 1785 The Land Ordinance of 1785 was adopted by the United States Congress of the Confederation on May 20, 1785. It set up a standardized system whereby settlers could purchase title to farmland in the undeveloped west. Congress at the time did not have ...
created the
Public Land Survey System The Public Land Survey System (PLSS) is the surveying method developed and used in the United States to plat, or divide, real property for sale and settling. Also known as the Rectangular Survey System, it was created by the Land Ordinance of 1 ...
. It formed the basis for dividing the western territories into sections to allow the sale of land. The PLSS divided states into township grids which were further divided into sections and fractions of sections.
Napoleon Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...
Bonaparte founded
continental Europe Continental Europe or mainland Europe is the contiguous continent of Europe, excluding its surrounding islands. It can also be referred to ambiguously as the European continent, – which can conversely mean the whole of Europe – and, by ...
's first
cadastre A cadastre or cadaster is a comprehensive recording of the real estate or real property's metes and bounds, metes-and-bounds of a country.Jo Henssen, ''Basic Principles of the Main Cadastral Systems in the World,'/ref> Often it is represented gra ...
in 1808. This gathered data on the number of parcels of land, their value, land usage, and names. This system soon spread around Europe. Robert Torrens introduced the
Torrens system Torrens title is a land registration and land transfer system, in which a state creates and maintains a register of land holdings, which serves as the conclusive evidence (termed " indefeasibility") of title of the person recorded on the regist ...
in South Australia in 1858. Torrens intended to simplify land transactions and provide reliable titles via a centralized register of land. The Torrens system was adopted in several other nations of the English-speaking world. Surveying became increasingly important with the arrival of railroads in the 1800s. Surveying was necessary so that railroads could plan technologically and financially viable routes.


20th century

At the beginning of the century surveyors had improved the older chains and ropes, but still faced the problem of accurate measurement of long distances. Dr Trevor Lloyd Wadley developed the
Tellurometer The tellurometer was the first successful microwave electronic distance measurement equipment. The name derives from the Latin ''tellus'', meaning Earth. History The original tellurometer, known as the Micro-Distancer MRA 1, was introduced in 19 ...
during the 1950s. It measures long distances using two microwave transmitter/receivers. During the late 1950s
Geodimeter __NOTOC__ The Geodimeter (acronym of geodetic distance meter) was the first optical electronic distance meter surveying instrument. It was originally developed for measuring the speed of light. It was invented in 1947 by and commercialized in 195 ...
introduced
electronic distance measurement Length measurement, distance measurement, or range measurement (ranging) refers to the many ways in which length, distance, or range can be measured. The most commonly used approaches are the rulers, followed by transit-time methods and the int ...
(EDM) equipment. EDM units use a multi frequency phase shift of light waves to find a distance. These instruments saved the need for days or weeks of chain measurement by measuring between points kilometers apart in one go. Advances in electronics allowed miniaturization of EDM. In the 1970s the first instruments combining angle and distance measurement appeared, becoming known as
total station A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure b ...
s. Manufacturers added more equipment by degrees, bringing improvements in accuracy and speed of measurement. Major advances include tilt compensators, data recorders, and on-board calculation programs. The first satellite positioning system was the
US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...
TRANSIT system Public transport (also known as public transportation, public transit, mass transit, or simply transit) is a system of transport for passengers by group travel systems available for use by the general public unlike private transport, typical ...
. The first successful launch took place in 1960. The system's main purpose was to provide position information to
Polaris missile The UGM-27 Polaris missile was a two-stage solid-fueled nuclear-armed submarine-launched ballistic missile (SLBM). As the United States Navy's first SLBM, it served from 1961 to 1980. In the mid-1950s the Navy was involved in the Jupiter missile ...
submarines. Surveyors found they could use field receivers to determine the location of a point. Sparse satellite cover and large equipment made observations laborious, and inaccurate. The main use was establishing benchmarks in remote locations. The US Air Force launched the first prototype satellites of the
Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS) in 1978. GPS used a larger constellation of satellites and improved signal transmission to provide more accuracy. Early GPS observations required several hours of observations by a static receiver to reach survey accuracy requirements. Recent improvements to both satellites and receivers allow
Real Time Kinematic Real-time kinematic positioning (RTK) is the application of surveying to correct for common errors in current satellite navigation (GNSS) systems. It uses measurements of the phase of the signal's carrier wave in addition to the information conte ...
(RTK) surveying. RTK surveys get high-accuracy measurements by using a fixed base station and a second roving antenna. The position of the roving antenna can be tracked.


21st century

The
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...
,
total station A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure b ...
, and RTK
GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
survey remain the primary methods in use. Remote sensing and satellite imagery continue to improve and become cheaper, allowing more commonplace use. Prominent new technologies include three-dimensional (3D) scanning and use of
lidar Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...
for topographical surveys.
UAV An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
technology along with
photogrammetric Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant ima ...
image processing is also appearing.


Equipment


Hardware

The main surveying instruments in use around the world are the
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...
,
measuring tape A tape measure or measuring tape is a flexible ruler used to measure length or distance. It consists of a ribbon of cloth, plastic, fibre glass, or metal strip with linear measurement markings. It is a common measuring tool. Its design all ...
,
total station A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure b ...
,
3D scanner 3D scanning is the process of analyzing a real-world object or environment to collect data on its shape and possibly its appearance (e.g. color). The collected data can then be used to construct digital 3D modelling, 3D models. A 3D scanner can ...
s,
GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
/
GNSS A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pre ...
,
level Level or levels may refer to: Engineering *Level (instrument), a device used to measure true horizontal or relative heights *Spirit level, an instrument designed to indicate whether a surface is horizontal or vertical *Canal pound or level *Regr ...
and rod. Most instruments screw onto a
tripod A tripod is a portable three-legged frame or stand, used as a platform for supporting the weight and maintaining the stability of some other object. The three-legged (triangular stance) design provides good stability against gravitational loads ...
when in use. Tape measures are often used for measurement of smaller distances. 3D scanners and various forms of aerial imagery are also used. The theodolite is an instrument for the measurement of angles. It uses two separate ''circles'', ''protractors'' or ''alidades'' to measure angles in the horizontal and the vertical plane. A telescope mounted on trunnions is aligned vertically with the target object. The whole upper section rotates for horizontal alignment. The vertical circle measures the angle that the telescope makes against the vertical, known as the zenith angle. The horizontal circle uses an upper and lower plate. When beginning the survey, the surveyor points the instrument in a known direction (bearing), and clamps the lower plate in place. The instrument can then rotate to measure the bearing to other objects. If no bearing is known or direct angle measurement is wanted, the instrument can be set to zero during the initial sight. It will then read the angle between the initial object, the theodolite itself, and the item that the telescope aligns with. The
gyrotheodolite In surveying, a gyrotheodolite (also: surveying gyro) is an instrument composed of a gyrocompass mounted to a theodolite. It is used to determine the orientation of true north. It is the main instrument for orientation in mine surveying and in tunn ...
is a form of theodolite that uses a gyroscope to orient itself in the absence of reference marks. It is used in underground applications. The
total station A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure b ...
is a development of the theodolite with an electronic distance measurement device (EDM). A total station can be used for leveling when set to the horizontal plane. Since their introduction, total stations have shifted from optical-mechanical to fully electronic devices. Modern top-of-the-line total stations no longer need a reflector or prism to return the light pulses used for distance measurements. They are fully robotic, and can even e-mail point data to a remote computer and connect to
satellite positioning system A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...
s, such as
Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
.
Real Time Kinematic Real-time kinematic positioning (RTK) is the application of surveying to correct for common errors in current satellite navigation (GNSS) systems. It uses measurements of the phase of the signal's carrier wave in addition to the information conte ...
GPS systems have significantly increased the speed of surveying, and they are now horizontally accurate to within 1 cm ± 1 ppm in real-time, while vertically it is currently about half of that to within 2 cm ± 2 ppm. GPS surveying differs from other GPS uses in the equipment and methods used. Static GPS uses two receivers placed in position for a considerable length of time. The long span of time lets the receiver compare measurements as the satellites orbit. The changes as the satellites orbit also provide the measurement network with well conditioned geometry. This produces an accurate baseline that can be over 20 km long. RTK surveying uses one static antenna and one roving antenna. The static antenna tracks changes in the satellite positions and atmospheric conditions. The surveyor uses the roving antenna to measure the points needed for the survey. The two antennas use a radio link that allows the static antenna to send corrections to the roving antenna. The roving antenna then applies those corrections to the GPS signals it is receiving to calculate its own position. RTK surveying covers smaller distances than static methods. This is because divergent conditions further away from the base reduce accuracy. Surveying instruments have characteristics that make them suitable for certain uses. Theodolites and levels are often used by constructors rather than surveyors in first world countries. The constructor can perform simple survey tasks using a relatively cheap instrument. Total stations are workhorses for many professional surveyors because they are versatile and reliable in all conditions. The productivity improvements from a GPS on large scale surveys makes them popular for major infrastructure or data gathering projects. One-person robotic-guided total stations allow surveyors to measure without extra workers to aim the telescope or record data. A fast but expensive way to measure large areas is with a helicopter, using a GPS to record the location of the helicopter and a laser scanner to measure the ground. To increase precision, surveyors place
beacons A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More mod ...
on the ground (about apart). This method reaches precisions between 5–40 cm (depending on flight height). Surveyors use ancillary equipment such as tripods and instrument stands; staves and beacons used for sighting purposes; PPE; vegetation clearing equipment; digging implements for finding survey markers buried over time; hammers for placements of markers in various surfaces and structures; and portable radios for communication over long lines of sight.


Software

Land surveyors, construction professionals, and civil engineers using
total station A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure b ...
,
GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
, 3D scanners, and other collector data use Land Surveying Software to increase efficiency, accuracy, and productivity. Land Surveying Software is a staple of contemporary land surveying. Typically, much if not all of the drafting and some of the
design A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...
ing for
plans A plan is typically any diagram or list of steps with details of timing and resources, used to achieve an objective to do something. It is commonly understood as a temporal set of intended actions through which one expects to achieve a goal. ...
and
plat In the United States, a plat ( or ) (plan) is a cadastral map, drawn to scale, showing the divisions of a piece of land. United States General Land Office surveyors drafted township plats of Public Lands Surveys to show the distance and bear ...
s of the surveyed property is done by the surveyor, and nearly everyone working in the area of drafting today (2021) utilizes
CAD Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...
software and hardware both on PC, and more and more in newer generation data collectors in the field as well. Other computer platforms and tools commonly used today by surveyors are offered online by the
U.S. Federal Government The federal government of the United States (U.S. federal government or U.S. government) is the Federation#Federal governments, national government of the United States, a federal republic located primarily in North America, composed of 50 ...
and other governments' survey agencies, such as the
National Geodetic Survey The National Geodetic Survey (NGS) is a List of federal agencies in the United States, United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping an ...
and the CORS network, to get automated corrections and conversions for collected
GPS The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
data, and the data
coordinate systems In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements on a manifold such as Euclidean space. The order of the coordinates is sign ...
themselves.


Techniques

Surveyors determine the position of objects by measuring angles and distances. The factors that can affect the accuracy of their observations are also measured. They then use this data to create vectors, bearings, coordinates, elevations, areas, volumes, plans and maps. Measurements are often split into horizontal and vertical components to simplify calculation. GPS and astronomic measurements also need measurement of a time component.


Distance measurement

Before
EDM EDM or E-DM may refer to: Music * Electronic dance music * Early Day Miners, American band Science and technology * Electric dipole moment * Electrical discharge machining * Electronic distance measurement *Entry, Descent, and landing demonstrat ...
(Electronic Distance Measurement) laser devices,
distance Distance is a numerical or occasionally qualitative measurement of how far apart objects or points are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two counties over"). ...
s were measured using a variety of means. These included chains with links of a known length such as a
Gunter's chain Gunter's chain (also known as Gunter’s measurement) is a distance measuring device used for surveying. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter (1581–1626). It enabled plots of land to be a ...
, or measuring tapes made of steel or
invar Invar, also known generically as FeNi36 (64FeNi in the US), is a nickel–iron alloy notable for its uniquely low coefficient of thermal expansion (CTE or α). The name ''Invar'' comes from the word ''invariable'', referring to its relative lac ...
. To measure horizontal distances, these chains or tapes were pulled taut to reduce sagging and slack. The distance had to be adjusted for heat expansion. Attempts to hold the measuring instrument level would also be made. When measuring up a slope, the surveyor might have to "break" (break chain) the measurement- use an increment less than the total length of the chain. Perambulators, or measuring wheels, were used to measure longer distances but not to a high level of accuracy.
Tacheometry Tacheometry (; from Greek for "quick measure") is a system of rapid surveying, by which the horizontal and vertical positions of points on the earth's surface relative to one another are determined without using a chain or tape, or a separate l ...
is the science of measuring distances by measuring the angle between two ends of an object with a known size. It was sometimes used before to the invention of EDM where rough ground made chain measurement impractical.


Angle measurement

Historically, horizontal angles were measured by using a
compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...
to provide a magnetic bearing or azimuth. Later, more precise scribed discs improved angular resolution. Mounting telescopes with
reticle A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, ...
s atop the disc allowed more precise sighting (see
theodolite A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and i ...
). Levels and calibrated circles allowed the measurement of vertical angles. Verniers allowed measurement to a fraction of a degree, such as with a turn-of-the-century
transit Transit may refer to: Arts and entertainment Film * ''Transit'' (1979 film), a 1979 Israeli film * ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world * ''Transit'' (2006 film), a 2006 ...
. The
plane table A plane table (plain table prior to 1830) is a device used in surveying site mapping, exploration mapping, coastal navigation mapping, and related disciplines to provide a solid and level surface on which to make field drawings, charts and maps. ...
provided a graphical method of recording and measuring angles, which reduced the amount of mathematics required. In 1829
Francis Ronalds Sir Francis Ronalds FRS (21 February 17888 August 1873) was an English scientist and inventor, and arguably the first electrical engineer. He was knighted for creating the first working electric telegraph over a substantial distance. In 1816 ...
invented a
reflecting instrument Reflecting instruments are those that use mirrors to enhance their ability to make measurements. In particular, the use of mirrors permits one to observe two objects simultaneously while measuring the angular distance between the objects. While re ...
for recording angles graphically by modifying the octant. By observing the bearing from every vertex in a figure, a surveyor can measure around the figure. The final observation will be between the two points first observed, except with a 180° difference. This is called a ''close''. If the first and last bearings are different, this shows the error in the survey, called the ''angular misclose''. The surveyor can use this information to prove that the work meets the expected standards.


Levelling

The simplest method for measuring height is with an
altimeter An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water. The m ...
 using air pressure to find the height. When more precise measurements are needed, means like precise levels (also known as differential leveling) are used. When precise leveling, a series of measurements between two points are taken using an instrument and a measuring rod. Differences in height between the measurements are added and subtracted in a series to get the net difference in elevation between the two endpoints. With the
Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS), elevation can be measured with satellite receivers. Usually, GPS is somewhat less accurate than traditional precise leveling, but may be similar over long distances. When using an optical level, the endpoint may be out of the effective range of the instrument. There may be obstructions or large changes of elevation between the endpoints. In these situations, extra setups are needed. ''Turning'' is a term used when referring to moving the level to take an elevation shot from a different location. To "turn" the level, one must first take a reading and record the elevation of the point the rod is located on. While the rod is being kept in exactly the same location, the level is moved to a new location where the rod is still visible. A reading is taken from the new location of the level and the height difference is used to find the new elevation of the level gun, which is why this method is referred to as ''differential levelling''. This is repeated until the series of measurements is completed. The level must be horizontal to get a valid measurement. Because of this, if the horizontal crosshair of the instrument is lower than the base of the rod, the surveyor will not be able to sight the rod and get a reading. The rod can usually be raised up to high, allowing the level to be set much higher than the base of the rod.


Determining position

The primary way of determining one's position on the earth's surface when no known positions are nearby is by astronomic observations. Observations to the sun, moon and stars could all be made using navigational techniques. Once the instrument's position and bearing to a star is determined, the bearing can be transferred to a reference point on the earth. The point can then be used as a base for further observations. Survey-accurate astronomic positions were difficult to observe and calculate and so tended to be a base off which many other measurements were made. Since the advent of the GPS system, astronomic observations are rare as GPS allows adequate positions to be determined over most of the surface of the earth.


Reference networks

Few survey positions are derived from the first principles. Instead, most surveys points are measured relative to previously measured points. This forms a reference or ''control'' network where each point can be used by a surveyor to determine their own position when beginning a new survey. Survey points are usually marked on the earth's surface by objects ranging from small nails driven into the ground to large beacons that can be seen from long distances. The surveyors can set up their instruments in this position and measure to nearby objects. Sometimes a tall, distinctive feature such as a steeple or radio aerial has its position calculated as a reference point that angles can be measured against. ''
Triangulation In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle me ...
'' is a method of horizontal location favoured in the days before EDM and GPS measurement. It can determine distances, elevations and directions between distant objects. Since the early days of surveying, this was the primary method of determining accurate positions of objects for
topographic Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary scie ...
maps of large areas. A surveyor first needs to know the horizontal distance between two of the objects, known as the baseline. Then the heights, distances and angular position of other objects can be derived, as long as they are visible from one of the original objects. High-accuracy transits or theodolites were used, and angle measurements were repeated for increased accuracy. See also
Triangulation in three dimensions In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle m ...
. ''Offsetting'' is an alternate method of determining the position of objects, and was often used to measure imprecise features such as riverbanks. The surveyor would mark and measure two known positions on the ground roughly parallel to the feature, and mark out a baseline between them. At regular intervals, a distance was measured at right angles from the first line to the feature. The measurements could then be plotted on a plan or map, and the points at the ends of the offset lines could be joined to show the feature. ''Traversing'' is a common method of surveying smaller areas. The surveyor starts from an old reference mark or known position and places a network of reference marks covering the survey area. They then measure bearings and distances between the reference marks, and to the target features. Most traverses form a loop pattern or link between two prior reference marks so the surveyor can check their measurements.


Datum and coordinate systems

Many surveys do not calculate positions on the surface of the earth, but instead, measure the relative positions of objects. However, often the surveyed items need to be compared to outside data, such as boundary lines or previous survey's objects. The oldest way of describing a position is via latitude and longitude, and often a height above sea level. As the surveying profession grew it created Cartesian coordinate systems to simplify the mathematics for surveys over small parts of the earth. The simplest coordinate systems assume that the earth is flat and measure from an arbitrary point, known as a 'datum' (singular form of data). The coordinate system allows easy calculation of the distances and direction between objects over small areas. Large areas distort due to the earth's curvature. North is often defined as true north at the datum. For larger regions, it is necessary to model the shape of the earth using an ellipsoid or a geoid. Many countries have created coordinate-grids customized to lessen error in their area of the earth.


Errors and accuracy

A basic tenet of surveying is that no measurement is perfect, and that there will always be a small amount of error. There are three classes of survey errors: *''Gross errors or blunders:'' Errors made by the surveyor during the survey. Upsetting the instrument, misaiming a target, or writing down a wrong measurement are all gross errors. A large gross error may reduce the accuracy to an unacceptable level. Therefore, surveyors use redundant measurements and independent checks to detect these errors early in the survey. *''Systematic:'' Errors that follow a consistent pattern. Examples include effects of temperature on a chain or EDM measurement, or a poorly adjusted spirit-level causing a tilted instrument or target pole. Systematic errors that have known effects can be compensated or corrected. *''Random:'' Random errors are small unavoidable fluctuations. They are caused by imperfections in measuring equipment, eyesight, and conditions. They can be minimized by redundancy of measurement and avoiding unstable conditions. Random errors tend to cancel each other out, but checks must be made to ensure they are not propagating from one measurement to the next. Surveyors avoid these errors by calibrating their equipment, using consistent methods, and by good design of their reference network. Repeated measurements can be averaged and any outlier measurements discarded. Independent checks like measuring a point from two or more locations or using two different methods are used, and errors can be detected by comparing the results of two or more measurements, thus utilizing redundancy. Once the surveyor has calculated the level of the errors in his or her work, it is adjusted. This is the process of distributing the error between all measurements. Each observation is weighted according to how much of the total error it is likely to have caused and part of that error is allocated to it in a proportional way. The most common methods of adjustment are the Bowditch method, also known as the compass rule, and the principle of least squares method. The surveyor must be able to distinguish between
accuracy and precision Accuracy and precision are two measures of ''observational error''. ''Accuracy'' is how close a given set of measurements ( observations or readings) are to their ''true value'', while ''precision'' is how close the measurements are to each oth ...
. In the United States, surveyors and civil engineers use units of feet wherein a survey foot breaks down into 10ths and 100ths. Many deed descriptions containing distances are often expressed using these units (125.25 ft). On the subject of accuracy, surveyors are often held to a standard of one one-hundredth of a foot; about 1/8 inch. Calculation and mapping tolerances are much smaller wherein achieving near-perfect closures are desired. Though tolerances will vary from project to project, in the field and day to day usage beyond a 100th of a foot is often impractical.


Types

Local organisations or regulatory bodies class specializations of surveying in different ways. Broad groups are: * ''As-built survey'': a survey that documents the location of recently constructed elements of a construction project. As-built surveys are done for record, completion evaluation and payment purposes. An as-built survey is also known as a 'works as executed survey'. As built surveys are often presented in red or redline and laid over existing plans for comparison with design information. * '' Cadastral or boundary surveying'': a survey that establishes or re-establishes boundaries of a parcel using a
legal description A land description location of the written words which delineate a specific piece of real property. Also known as a "Legal Description". In the written transfer of real property, it is universally required that the instrument of conveyance (deed ...
. It involves the setting or restoration of monuments or markers at the corners or along the boundaries of a parcel. These take the form of iron rods,
pipes Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circula ...
, or concrete monuments in the ground, or nails set in concrete or asphalt. The ''ALTA/ACSM'' Land Title Survey is a standard proposed by the
American Land Title Association The American Land Title Association (ALTA), founded in 1907, is the national trade association representing more than 6,400 title insurance companies, title and settlement agents, independent abstracters, title searchers and real estate attorneys ...
and the
American Congress on Surveying and Mapping The American Congress on Surveying and Mapping (ACSM) was an American professional association representing the interests of those engaged in measuring and communicating geospatial data. Originally, it was composed of four organizations: * America ...
. It incorporates elements of the boundary survey, mortgage survey, and topographic survey. * ''Control surveying'': Control surveys establish reference points to use as starting positions for future surveys. Most other forms of surveying will contain elements of control surveying. * ''
Construction surveying Construction surveying or building surveying (otherwise known as "staking", "stake-out", "lay-out", "setting-out" or "BS") is to stake out reference points and markers that will guide the construction of new structures such as roads or buildings. T ...
'' and ''engineering surveying'': topographic, layout, and as-built surveys associated with engineering design. They often need geodetic computations beyond normal civil engineering practice. * '' Deformation survey:'' a survey to determine if a structure or object is changing shape or moving. First the positions of points on an object are found. A period of time is allowed to pass and the positions are then re-measured and calculated. Then a comparison between the two sets of positions is made. * ''
Dimensional control survey In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coord ...
:'' This is a type of survey conducted in or on a non-level surface. Common in the oil and gas industry to replace old or damaged pipes on a like-for-like basis, the advantage of dimensional control survey is that the instrument used to conduct the survey does not need to be level. This is useful in the off-shore industry, as not all platforms are fixed and are thus subject to movement. * ''Foundation survey'': a survey done to collect the positional data on a foundation that has been poured and is cured. This is done to ensure that the foundation was constructed in the location, and at the elevation, authorized in the ''plot plan'', ''site plan'', or ''subdivision plan''. * ''
Hydrographic survey Hydrographic survey is the science of measurement and description of features which affect maritime navigation, marine construction, dredging, offshore oil exploration/offshore oil drilling and related activities. Strong emphasis is placed ...
'': a survey conducted with the purpose of mapping the shoreline and bed of a body of water. Used for navigation, engineering, or resource management purposes. * ''
Leveling Levelling or leveling (American English; see spelling differences) is a branch of surveying, the object of which is to establish or verify or measure the height of specified points relative to a datum. It is widely used in geodesy and cartogra ...
'': either finds the elevation of a given point or establish a point at a given elevation. * '' LOMA survey'': Survey to change base flood line, removing property from a SFHA special flood hazard area. * ''Measured survey'' : a building survey to produce plans of the building. such a survey may be conducted before renovation works, for commercial purpose, or at end of the construction process. * '' Mining surveying'': Mining surveying includes directing the digging of mine shafts and galleries and the calculation of volume of rock. It uses specialised techniques due to the restraints to survey geometry such as vertical shafts and narrow passages. * ''Mortgage survey:'' A ''mortgage survey'' or ''physical survey'' is a simple survey that delineates land boundaries and building locations. It checks for ''
encroachment Encroachment is to advance beyond proper limits, and may refer to: * Temporal encroachment * Structural encroachment * Encroachment (gridiron football), a penalty in American and Canadian football *Encroachment by human populations on natural spa ...
'', building setback restrictions and shows nearby flood zones. In many places a mortgage survey is a precondition for a mortgage loan. * '' Photographic control survey'': A survey that creates reference marks visible from the air to allow
aerial photographs Aerial photography (or airborne imagery) is the taking of photographs from an aircraft or other airborne platforms. When taking motion pictures, it is also known as aerial videography. Platforms for aerial photography include fixed-wing aircra ...
to be rectified. * ''Stakeout, layout or setout'': an element of many other surveys where the calculated or proposed position of an object is marked on the ground. This can be temporary or permanent. This is an important component of engineering and cadastral surveying. * ''Structural survey'': a detailed inspection to report upon the physical condition and structural stability of a building or structure. It highlights any work needed to maintain it in good repair. * ''Subdivision'': A boundary survey that splits a property into two or more smaller properties. * ''Topographic survey'': a survey of the positions and elevations of points and objects on a land surface, presented as a
topographic map In modern mapping, a topographic map or topographic sheet is a type of map characterized by large- scale detail and quantitative representation of relief features, usually using contour lines (connecting points of equal elevation), but historic ...
with
contour line A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional grap ...
s. * ''Existing conditions'': Similar to a topographic survey but instead focuses more on the specific location of key features and structures as they exist at that time within the surveyed area rather than primarily focusing on the elevation, often used alongside architectural drawings and
blueprints A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets. Introduced by Sir John Herschel in 1842, the process allowed rapid and accurate production of an unlimited number ...
to locate or place building structures. * ''
Underwater survey An underwater survey is a survey performed in an underwater environment or conducted remotely on an underwater object or region. Survey can have several meanings. The word originates in Medieval Latin with meanings of ''looking over'' and ''detail ...
'': a survey of an underwater site, object, or area.


Plane vs. geodetic surveying

Based on the considerations and true shape of the earth, surveying is broadly classified into two types. ''Plane surveying'' assumes the earth is flat. Curvature and spheroidal shape of the earth is neglected. In this type of surveying all triangles formed by joining survey lines are considered as plane triangles. It is employed for small survey works where errors due to the earth's shape are too small to matter. In ''
geodetic surveying Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure ( geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equiva ...
'' the curvature of the earth is taken into account while calculating reduced levels, angles, bearings and distances. This type of surveying is usually employed for large survey works. Survey works up to 100 square miles (260 square kilometers ) are treated as plane and beyond that are treated as geodetic. In geodetic surveying necessary corrections are applied to reduced levels, bearings and other observations.


On the basis of the instrument used

* Chain Surveying * Compass Surveying * Plane table Surveying * Levelling * Theodolite Surveying * Traverse Surveying * Tacheometric Surveying * Aerial Surveying


Profession

The basic principles of surveying have changed little over the ages, but the tools used by surveyors have evolved. Engineering, especially civil engineering, often needs surveyors. Surveyors help determine the placement of roads, railways, reservoirs, dams,
pipeline Pipeline may refer to: Electronics, computers and computing * Pipeline (computing), a chain of data-processing stages or a CPU optimization found on ** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...
s,
retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...
s, bridges, and buildings. They establish the boundaries of legal descriptions and political divisions. They also provide advice and data for ''
geographical information system A geographic information system (GIS) is a type of database containing geographic data (that is, descriptions of phenomena for which location is relevant), combined with software tools for managing, analyzing, and visualizing those data. In a br ...
s'' (GIS) that record land features and boundaries. Surveyors must have a thorough knowledge of
algebra Algebra () is one of the broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathematics. Elementary a ...
, basic
calculus Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizations of arithm ...
,
geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is c ...
, and
trigonometry Trigonometry () is a branch of mathematics that studies relationships between side lengths and angles of triangles. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies. T ...
. They must also know the laws that deal with surveys,
real property In English common law, real property, real estate, immovable property or, solely in the US and Canada, realty, is land which is the property of some person and all structures (also called improvements or fixtures) integrated with or affixe ...
, and contracts. Most jurisdictions recognize three different levels of qualification: # ''Survey assistants'' or ''chainmen'' are usually unskilled workers who help the surveyor. They place target reflectors, find old reference marks, and mark points on the ground. The term 'chainman' derives from past use of
measuring chain Gunter's chain (also known as Gunter’s measurement) is a distance measuring device used for surveying. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter (1581–1626). It enabled plots of land to be a ...
s. An assistant would move the far end of the chain under the surveyor's direction. # ''Survey technicians'' often operate survey instruments, run surveys in the field, do survey calculations, or draft plans. A technician usually has no legal authority and cannot certify his work. Not all technicians are qualified, but qualifications at the certificate or diploma level are available. # ''Licensed, registered, or
chartered surveyors Chartered Surveyor is the description (protected by law in many countries) of Professional ''Members'' and ''Fellows'' of the Royal Institution of Chartered Surveyors (RICS) entitled to use the designation (and a number of variations such as "Charte ...
'' usually hold a degree or higher qualification. They are often required to pass further exams to join a professional association or to gain certifying status. Surveyors are responsible for planning and management of surveys. They have to ensure that their surveys, or surveys performed under their supervision, meet the legal standards. Many principals of surveying firms hold this status. Related professions include
cartographer Cartography (; from grc, χάρτης , "papyrus, sheet of paper, map"; and , "write") is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an im ...
s,
hydrographer Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers, as well as with the prediction of their change over time, for the primary p ...
s,
geodesist Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...
s,
photogrammetrist Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant ima ...
s, and
topographer Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary scie ...
s, as well as
civil engineer A civil engineer is a person who practices civil engineering – the application of planning, designing, constructing, maintaining, and operating infrastructure while protecting the public and environmental health, as well as improving existing ...
s and
geomatics engineer Geomatics is defined in the ISO/TC 211 series of standards as the " discipline concerned with the collection, distribution, storage, analysis, processing, presentation of geographic data or geographic information". Under another definition, i ...
s.


Licensing

Licensing requirements vary with jurisdiction, and are commonly consistent within national borders. Prospective surveyors usually have to receive a degree in surveying, followed by a detailed examination of their knowledge of surveying law and principles specific to the region they wish to practice in, and undergo a period of on-the-job training or portfolio building before they are awarded a license to practise. Licensed surveyors usually receive a
post nominal Post-nominal letters, also called post-nominal initials, post-nominal titles, designatory letters or simply post-nominals, are letters placed after a person's name to indicate that the individual holds a position, academic degree, accreditation, ...
, which varies depending on where they qualified. The system has replaced older apprenticeship systems. A licensed land surveyor is generally required to sign and seal all plans. The state dictates the format, showing their name and registration number. In many jurisdictions, surveyors must mark their registration number on
survey monument Survey markers, also called survey marks, survey monuments, or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying. A ''benchmark'' is a type of survey marker that i ...
s when setting boundary corners. Monuments take the form of capped iron rods, concrete monuments, or nails with washers.


Surveying institutions

Most countries' governments regulate at least some forms of surveying. Their survey agencies establish regulations and standards. Standards control accuracy, surveying credentials, monumentation of boundaries and maintenance of
geodetic network A geodetic control network (also geodetic network, reference network, control point network, or control network) is a network, often of triangles, which are measured precisely by techniques of terrestrial surveying or by satellite geodesy. A ...
s. Many nations devolve this authority to regional entities or states/provinces. Cadastral surveys tend to be the most regulated because of the permanence of the work. Lot boundaries established by cadastral surveys may stand for hundreds of years without modification. Most jurisdictions also have a form of professional institution representing local surveyors. These institutes often endorse or license potential surveyors, as well as set and enforce ethical standards. The largest institution is the
International Federation of Surveyors International Federation of Surveyors (abbreviated FIG, after the french: Fédération Internationale des Géomètres) is the UN-recognized global organization for the profession of surveying and related disciplines. It was established in 1878,
(Abbreviated FIG, for french: link=no, Fédération Internationale des Géomètres). They represent the survey industry worldwide.


Building surveying

Most English-speaking countries consider building surveying a distinct profession. They have their own professional associations and licensing requirements. A building surveyor can provide technical building advice on existing buildings, new buildings, design, compliance with regulations such as planning and building control. A building surveyor normally acts on behalf of his or her client ensuring that their vested interests remain protected. The Royal Institution of Chartered Surveyors (RICS) is a world-recognised governing body for those working within the built environment.


Cadastral surveying

One of the primary roles of the land surveyor is to determine the boundary of real property on the ground. The surveyor must determine where the adjoining landowners wish to put the boundary. The boundary is established in legal documents and plans prepared by attorneys, engineers, and land surveyors. The surveyor then puts monuments on the corners of the new boundary. They might also find or resurvey the corners of the property monumented by prior surveys. ''Cadastral land surveyors'' are licensed by governments. The cadastral survey branch of the
Bureau of Land Management The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's la ...
(BLM) conducts most cadastral surveys in the United States. They consult with Forest Service,
National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propertie ...
, Army Corps of Engineers,
Bureau of Indian Affairs The Bureau of Indian Affairs (BIA), also known as Indian Affairs (IA), is a United States federal agency within the Department of the Interior. It is responsible for implementing federal laws and policies related to American Indians and A ...
,
Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...
,
Bureau of Reclamation The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...
, and others. The BLM used to be known as the
General Land Office The General Land Office (GLO) was an independent agency of the United States government responsible for public domain lands in the United States. It was created in 1812 to take over functions previously conducted by the United States Department o ...
(GLO). In states organized per the
Public Land Survey System The Public Land Survey System (PLSS) is the surveying method developed and used in the United States to plat, or divide, real property for sale and settling. Also known as the Rectangular Survey System, it was created by the Land Ordinance of 1 ...
(PLSS), surveyors must carry out BLM cadastral surveys under that system. Cadastral surveyors often have to work around changes to the earth that obliterate or damage boundary monuments. When this happens, they must consider evidence that is not recorded on the title deed. This is known as extrinsic evidence.Richards, D., & Hermansen, K. (1995). Use of extrinsic evidence to aid interpretation of deeds. Journal of Surveying Engineering, (121), 178.


Noteworthy surveyors

Some U.S. Presidents were land surveyors.
George Washington George Washington (February 22, 1732, 1799) was an American military officer, statesman, and Founding Father who served as the first president of the United States from 1789 to 1797. Appointed by the Continental Congress as commander of th ...
and
Abraham Lincoln Abraham Lincoln ( ; February 12, 1809 – April 15, 1865) was an American lawyer, politician, and statesman who served as the 16th president of the United States from 1861 until his assassination in 1865. Lincoln led the nation thro ...
surveyed Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Two-dimensional space#In geometry, two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of ...
colonial or frontier territories early in their career, prior to serving in office.
David T. Abercrombie David Thomas Abercrombie (June 6, 1867 – August 29, 1931) was the founder of the American lifestyle brand Abercrombie & Fitch. A topographer and expert in the outdoors, Abercrombie opened the company as New York's outfitter for the elite ...
practiced land surveying before starting an
outfitter An outfitter is a shop or person that sells specialized clothes (an ''outfit'' is a set of clothing). More specifically, it is a company or individual who provides or deals in equipment and supplies for the pursuit of certain activities. In North ...
store of
excursion An excursion is a trip by a group of people, usually made for leisure, education, or physical purposes. It is often an adjunct to a longer journey or visit to a place, sometimes for other (typically work-related) purposes. Public transportation ...
goods. The business would later turn into
Abercrombie & Fitch Abercrombie & Fitch (A&F) is an American lifestyle retailer that focuses on casual wear. Its headquarters are in New Albany, Ohio. The company operates three other offshoot brands: Abercrombie Kids, Hollister Co., and Gilly Hicks. As of Februar ...
lifestyle clothing store.
Percy Harrison Fawcett Percy Harrison Fawcett (18 August 1867 during or after 1925) was a British geographer, artillery officer, cartographer, archaeologist, and explorer of South America. Fawcett disappeared in 1925 (along with his eldest son, Jack, and one of ...
was a British surveyor that explored the jungles of South America attempting to find the
Lost City of Z The Lost City of Z is the name given by Col. Percy Harrison Fawcett, a British surveyor, to an indigenous city that he believed had existed in the jungle of the Mato Grosso state of Brazil. Based on early histories of South America and his own e ...
. His biography and expeditions were recounted in the book ''The Lost City of Z'' and were later adapted on film screen.
Inō Tadataka was a Japanese people, Japanese surveying, surveyor and cartographer. He is known for completing the first map of Japan using modern surveying techniques. Early life Inō was born in the small village of Ozeki in the middle of Kujūkuri beach, ...
produced the first map of Japan using modern surveying techniques starting in 1800, at the age of 55.


See also

* * * * * * * *


References


Further reading

* * Keay J (2000), ''The Great Arc: The Dramatic Tale of How
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
was Mapped and
Everest Mount Everest (; Tibetan: ''Chomolungma'' ; ) is Earth's highest mountain above sea level, located in the Mahalangur Himal sub-range of the Himalayas. The China–Nepal border runs across its summit point. Its elevation (snow heigh ...
was Named'', Harper Collins, 182pp, . * Pugh J C (1975), ''Surveying for Field Scientists'', Methuen, 230pp, * Genovese I (2005), ''Definitions of Surveying and Associated Terms'', ACSM, 314pp, .


External links


Géomètres sans Frontières
: Association de géometres pour aide au développement. NGO Surveyors without borders
The National Museum of Surveying
The Home of the National Museum of Surveying in Springfield, Illinois
Land Surveyors United Support Network
Global social support network featuring surveyor forums, instructional videos, industry news and support groups based on geolocation.
Natural Resources Canada – Surveying
Good overview of surveying with references to construction surveys, cadastral surveys, photogrammetry surveys, mining surveys, hydrographic surveys, route surveys, control surveys and topographic surveys
Table of Surveying, 1728 Cyclopaedia

Surveying & Triangulation
The History of Surveying And Survey Equipment
NCEES
National Council of Examiners for Engineering and Surveying (NCEES)
NSPS
National Society of Professional Surveyors (NSPS)
Ground Penetrating Radar FAQ
Using Ground Penetrating Radar for Land Surveying
Survey Earth
A Global event for professional land surveyors and students to remeasure planet in a single day during summer solstice as a community of land surveyors.


Public Land Survey System Foundation (2009), ''Manual of Surveying Instructions For the Survey of the Public Lands of the United States''
{{Authority control Ancient Egyptian technology Civil engineering Land use