TheInfoList

Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions of points and the distances and angles 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 exclusive right In Anglo-Saxon law Anglo-Saxon law (Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language English is a West Germanic languages, West Germ ...
, 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 geometric shape, orientation in space, and gravitational field. The field also incorporates studies of how these properties change over time and equivalent measu ...
,
geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related with distance, shape, size, and relative position of figures. A mat ...

,
trigonometry Trigonometry (from ', "triangle" and ', "measure") is a branch of that studies relationships between side lengths and s of s. The field emerged in the during the 3rd century BC from applications of to . The Greeks focused on the , while ...

,
regression analysis In ing, regression analysis is a set of statistical processes for the relationships between a (often called the 'outcome' or 'response' variable) and one or more s (often called 'predictors', 'covariates', 'explanatory variables' or 'features' ...
,
physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of eve ...

, engineering,
metrology Metrology is the scientific study of measurement ' Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), attributes of an object or event, which can be used to compare with oth ...

,
programming language A programming language is a formal language In logic, mathematics, computer science, and linguistics, a formal language consists of string (computer science), words whose symbol (formal), letters are taken from an alphabet (computer science) ...

s, and the law. They use equipment, such as
total station Archaeological survey using a Leica TPS1100 total station on an Iron Age dwelling in Ytterby, Sweden. A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying Surveying or land surveying ...
s, robotic total stations,
theodolite A theodolite is a precision optical instrument for measuring angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), ...

s,
GNSS A satellite navigation or satnav system is a system that uses satellite alt=, A full-size model of the Earth observation satellite ERS 2 ">ERS_2.html" ;"title="Earth observation satellite ERS 2">Earth observation satellite ERS 2 In the ...
retroreflector A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that radiation (usually light) back to its source with minimum . This works at a wide range of , unlike a planar , which does this only if the mirror is exact ...
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. colour). The collected data can then be used to construct digital 3D modelling, 3D models. A 3D scanner can ...
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 *Canal pound or level *Regrading or levelling, the process of raising and/or lowering the levels of land *Storey or level ...

s, subsurface locators, drones,
GIS A geographic information system (GIS) is a conceptualized framework that provides the ability to capture and analyze spatial and geographic data. GIS applications (or GIS apps) are computer-based tools that allow the user to create interactive ...
, 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 is a historical narrative History (from Ancient Greek, Greek , ''historia'', meaning "inquiry; knowledge acquired by investigation") is the study of the past. Events occurring before the History of writing ...
. 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 (abbreviation, 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 establish ...
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 Ancient Egypt was a civilization  A civilization (or civilisation) is a that is characterized by , , a form of government, and systems of communication (such as ). Civilizations are intimately associated with additional char ...

, a
rope stretcher In ancient Egypt Ancient Egypt was a civilization of Ancient history, ancient North Africa, concentrated along the lower reaches of the Nile, Nile River, situated in the place that is now the country Egypt. Ancient Egyptian civilization fol ...
would use simple geometry to re-establish boundaries after the annual floods of the
Nile River The Nile, , Bohairic , lg, Kiira , Nobiin Nobiin, or Mahas, is a Northern Nubian languages, Nubian language of the Nilo-Saharan languages, Nilo-Saharan language family. "Nobiin" is the genitive case, genitive form of ''Nòòbíí'' ("Nub ...
. The almost perfect squareness and north–south orientation of the
Great Pyramid of Giza The Great Pyramid of Giza (also known as the Pyramid of Khufu or the Pyramid of Cheops) is the oldest and largest of the Egyptian pyramids, pyramids in the Giza pyramid complex bordering present-day Giza in Greater Cairo, Egypt. It is the olde ...

, built c. 2700 BC, affirm the Egyptians' command of surveying. The '' groma'' instrument originated in
Mesopotamia Mesopotamia ( grc, Μεσοποταμία ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the ...

(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 connecting ho ...

(c. 2500 BC) was set out by prehistoric surveyors using peg and rope geometry. The mathematician
Liu Hui Liu Hui () was a Chinese mathematician and writer who lived in the state of Cao Wei Wei (220–266), also known as Cao Wei or Former Wei, was one of the three major states that competed for supremacy over China in the Three Kingdoms ...
described ways of measuring distant objects in his work ''
Haidao Suanjing ''Haidao Suanjing'' (; ''The Sea Island Mathematical Manual'') was written by the of the era (220–280) as an extension of chapter 9 of '. L. van. Hee, ''Le Classique d I'Ile Maritime: Ouvrage Chinois de III'' siecle 1932 During the , t ...
'' 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 Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the R ...
''. In medieval Europe,
beating the bounds Beat, beats or beating may refer to: Common meanings Assigned activity or area * Patrol, an area (usually geographic) that one is responsible to monitor, including: ** Beat (police), the territory and time that a police officer patrols ** Beat ...
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 (c. 1028Bates ''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, monarch of Engl ...

commissioned the
Domesday Book Domesday Book () – the Middle English Middle English (abbreviated to ME) was a form of the English language spoken after the Norman conquest of England, Norman conquest (1066) until the late 15th century. The English language underwent ...
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 described a
plane table A plane table (plain table prior to 1830) is a device used in surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions of points and the distances and ang ...
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 Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions ...
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 qua ...
. 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 angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), ...

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, astronomy, astronomical and scientific instrument maker. His reputation was built on the engraving and design of dividing engines which allowed high accuracy ...
introduced the first precision
theodolite A theodolite is a precision optical instrument for measuring angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), ...

in 1787. It was an instrument for measuring
angle In Euclidean geometry Euclidean geometry is a mathematical system attributed to Alexandrian Greek mathematics , Greek mathematician Euclid, which he described in his textbook on geometry: the ''Euclid's Elements, Elements''. Euclid's method ...

s in the horizontal and vertical planes. He created his great theodolite using an accurate
dividing engine A dividing engine is a device employed to mark Graduation (instrument), 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 scr ...
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 Lord Chief Justice of England and Wales, Chief Justice of England during the reign of Henry IV of England, King Henry IV. Life and work Gascoigne (alternatively spelled Gascoyne) was a descen ...
invented an instrument that used a
telescope A telescope is an optical instrument An optical instrument (or "optic" for short) is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common ...

with an installed
crosshair scope of a Russian Dragunov sniper rifle, SVD designated marksman rifle. A reticle, or reticule (), also known as a graticule (), is a pattern of fine lines or markings built into the eyepiece of a sighting device, such as a telescopic sight in ...

as a target device, in 1640.
James Watt James Watt (; 30 January 1736 (19 January 1736 OS) – 25 August 1819) was a Scottish Scottish usually refers to something of, from, or related to Scotland, including: *Scottish Gaelic, a Celtic Goidelic language of the Indo-European lang ...

developed an optical meter for the measuring of distance in 1771; it measured the
parallactic angleIn 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 paral ...
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 An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Eart ...

(a.k.a. Snel van Royen) introduced the modern systematic use of
triangulation In trigonometry Trigonometry (from Greek '' trigōnon'', "triangle" and '' metron'', "measure") is a branch of mathematics Mathematics (from Ancient Greek, Greek: ) includes the study of such topics as quantity (number theory), mathe ...
. In 1615 he surveyed the distance from
Alkmaar Alkmaar is a List of cities in the Netherlands by province, city and List of municipalities of the Netherlands, municipality in the Netherlands, located in the Provinces of the Netherlands, province of North Holland. Alkmaar is well known for ...

to
Breda Breda (, , ) is a city A city is a large human settlement.Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. London: Routledge ...

, 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 F ...

and his son undertook the first triangulation of France. They included a re-surveying of the
meridian arc In geodesy Geodesy () is the Earth science Earth science or geoscience includes all fields of natural science Natural science is a branch of science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic ...
, 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 's cabinet of curiosities, from ''Museum Wormianum,'' 1655 An antiquarian or antiquary (from the Latin: ''antiquarius'', meaning ...
's
Ordnance Survey , nativename_a = , nativename_r = , logo = Ordnance Survey 2015 Logo.svg , logo_width = 240px , logo_caption = , seal = , seal_width = , seal_caption = , picture = , picture_width = , picture_caption = , formed = , preceding1 = , di ...
of Great Britain began the
Principal Triangulation of Britain The Principal Triangulation of Britain was the first high-precision trigonometric Trigonometry (from Ancient Greek, Greek ''wikt:τρίγωνον, trigōnon'', "triangle" and ''wikt:μέτρον, metron'', "measure") is a branch of mathemati ...
. 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 which aimed to measure 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 ...
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 (Chinese Chinese can refer to: * Something related to China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the List of countries and dependencies by population, world's ...

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 Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmasse ...
. The profession developed more accurate instruments to aid its work. Industrial infrastructure projects used surveyors to lay out
canal Canals are waterways channels Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * ...

s, roads and rail. In the US, the
Land Ordinance of 1785 #REDIRECT Land Ordinance of 1785#REDIRECT Land Ordinance of 1785The 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 farm ...
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 1785 ...

. 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 Napoléon Bonaparte (15 August 1769 – 5 May 1821) was a French military and political leader. He rose to prominence during the French Revolution The French Revolution ( ) refers to the period that began with the Estates General o ...

Bonaparte founded
continental Europe Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', lite ...

's first
cadastre A cadastral map (shortened to cadastre or cadaster) is a comprehensive land recording of the real estate Real estate is property consisting of land and the buildings on it, along with its natural resources such as crops, minerals or water; imm ...

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 TorrensRobert Torrens may refer to: * Robert Torrens (judge) Robert Torrens (1775 – 1856) was an Irish judge. He enjoyed, on the whole, a high reputation for impartiality and decency. While his critics called him "the notorious hanging Judge Torren ...

introduced the
Torrens system Torrens title is a land registration Land registration generally describes systems by which matters concerning ownership Ownership is the state or fact of exclusive rights and control over property Property (''latin: Res Privata'') in the A ...
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
TellurometerThe 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 195 ...
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 Speed of light#Measurement, measuring the speed of light. It was invented in 1947 by ...

introduced
electronic distance measurementThere are several devices to measure a length, distance, or Range of a projectile, range. Contact devices *Architect's scale *Caliper *Diagonal scale *Engineer's scale *Feeler gauge,used in metal working to measure size of gaps *Gauge blocks *Gun ...
(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 Archaeological survey using a Leica TPS1100 total station on an Iron Age dwelling in Ytterby, Sweden. A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying Surveying or land surveying ...
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 ), (unofficial)."''Non sibi sed patriae''" ( en, "Not for self but for country") (unofficial). , colors = Blue and gold  , colors_label = Colors , march = "Anchors Aweigh "Anchors Aweigh" is the fight song of the United States Naval A ...
TRANSIT system. 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-fuel rocket, solid-fueled nuclear warhead, nuclear-armed submarine-launched ballistic missile (SLBM). As the United States Navy's first SLBM, it served from 1961 to 1996. In the mid-1950s the Navy ...
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 The federal government of the United States (U.S. federal government or U.S. governme ...
(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 a satellite navigation A satellite navigation or satnav system is a system that uses satellite In the context of spaceflight, a satellite is an object that has been intentionally placed into orbit. ...
(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 angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), ...

,
total station Archaeological survey using a Leica TPS1100 total station on an Iron Age dwelling in Ytterby, Sweden. A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying Surveying or land surveying ...
, and RTK
GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government) is the national ...
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 with a laser A laser is a device that emits light Light or visible light is electromagnetic radiati ...
for topographical surveys.
UAV , a hunter-killer surveillance UAV , rotorcraft A rotorcraft or rotary-wing aircraft is a heavier-than-air aircraft An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters th ...

technology along with photogrammetric 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 angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), ...

,
measuring tape A tape measure or measuring tape is a flexible ruler used to measure size 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 allows ...

,
total station Archaeological survey using a Leica TPS1100 total station on an Iron Age dwelling in Ytterby, Sweden. A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying Surveying or land surveying ...
,
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. colour). 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 satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government) is the national ...
/
GNSS A satellite navigation or satnav system is a system that uses satellite alt=, A full-size model of the Earth observation satellite ERS 2 ">ERS_2.html" ;"title="Earth observation satellite ERS 2">Earth observation satellite ERS 2 In the ...
,
level Level or levels may refer to: Engineering * Level (instrument), a device used to measure true horizontal or relative heights *Canal pound or level *Regrading or levelling, the process of raising and/or lowering the levels of land *Storey or level ...
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 In science Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, test ...
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 Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions of points and the distances and angles between them. A land surveying professional is called a ...
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 Archaeological survey using a Leica TPS1100 total station on an Iron Age dwelling in Ytterby, Sweden. A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying Surveying or land surveying ...
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 systems, 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 The federal government of the United States (U.S. federal government or U.S. governme ...
.
Real Time Kinematic Real-time kinematic positioning (RTK) is a satellite navigation A satellite navigation or satnav system is a system that uses satellite In the context of spaceflight, a satellite is an object that has been intentionally placed into orbit. ...
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 A lighthouse is a tower, building, or another type of structure designed to emit light from a system of lam ...
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 Archaeological survey using a Leica TPS1100 total station on an Iron Age dwelling in Ytterby, Sweden. A total station (TS) or total station theodolite (TST) is an electronic/optical instrument used for surveying Surveying or land surveying ...
,
GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government) is the national ...

, 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 Drafting or draughting may refer to: * Campdrafting, an Australian equestrian sport * Drafting (aerodynamics), slipstreaming * Drafting (writing), writing something that is likely to be amended * Technical drawing, the act and discipline of compos ...

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 A prototype is an early sample, mode ...

ing for
plans A plan is typically any diagram A diagram is a symbolic Depiction, representation of information using Visualization (graphics), visualization techniques. Diagrams have been used since prehistoric times on Cave painting, walls of caves, but bec ...

and
plat In the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, st ...

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 comm ...
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 and other governments' survey agencies, such as the
National Geodetic Survey The National Geodetic Survey (NGS), formerly the United States Survey of the Coast (1807–1836), United States Coast Survey (1836–1878), and United States Coast and Geodetic Survey (USC&GS) (1878–1970), is a United States federal agency t ...
and the CORS network, to get automated corrections and conversions for collected
GPS The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government The federal government of the United States (U.S. federal government) is the national ...
data, and the data
coordinate systems In geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related with distance, shape, size, and relative position o ...
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 (Electronic Distance Measurement) laser devices,
distance Distance is a numerical measurement ' Measurement is the number, numerical quantification (science), quantification of the variable and attribute (research), attributes of an object or event, which can be used to compare with other objects or eve ...

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 Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions ...
, or measuring tapes made of steel or
invar Invar, also known generically as FeNi36 (64FeNi in the US), is a nickel Nickel is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an e ...
. 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 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 Circumferentor, compass to provide a magnetic bearing or azimuth. Later, more precise scribed discs improved angular resolution. Mounting telescopes with reticles atop the disc allowed more precise sighting (see
theodolite A theodolite is a precision optical instrument for measuring angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), ...

). Levels and calibrated circles allowed the measurement of vertical angles. Vernier scale, Verniers allowed measurement to a fraction of a degree, such as with a turn-of-the-century Transit (surveying), transit. The
plane table A plane table (plain table prior to 1830) is a device used in surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions of points and the distances and ang ...
provided a graphical method of recording and measuring angles, which reduced the amount of mathematics required. In 1829 Francis Ronalds invented a Reflecting instrument#Surveying sector, reflecting instrument for recording angles graphically by modifying the Octant (instrument), 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 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 The federal government of the United States (U.S. federal government or U.S. governme ...
(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 first principles. Instead, most surveys points are measured relative to previous 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 Trig beacon, large beacons that can be seen from long distances. The surveyors can set up their instruments on 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'' 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 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 repeated for increased accuracy. See also Triangulation in three dimensions. ''Offsetting'' is an alternate method of determining 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. Traverse (surveying), ''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 (engineering), redundancy. Once the surveyor has calculated the level of the errors in his or her work, it is adjustment of observations, 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 Nathaniel Bowditch, Bowditch method, also known as the compass rule, and the least squares, principle of least squares method. The surveyor must be able to distinguish between accuracy and precision. 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 surveying, Cadastral or boundary surveying'': a survey that establishes or re-establishes boundaries of a parcel using a Land description, legal description. It involves the setting or restoration of monuments or markers at the corners or along the lines of the parcel. These take the form of iron rods, Pipe (material), pipes, or concrete monuments in the ground, or Nail (fastener), nails set in concrete or asphalt. The ''ALTA/ACSM'' Land Title Survey is a standard proposed by the American Land Title Association and the American Congress on Surveying and Mapping. 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'' * ''Deformation Monitoring, 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:'' 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. * ''Engineering surveying'': topographic, layout, and as-built surveys associated with engineering design. They often need geodetic computations beyond normal civil engineering practice. * ''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'': 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'': either finds the elevation of a given point or establish a point at a given elevation. * ''National Flood Insurance Program#Removal from NFIP, LOMA survey'': Survey to change base flood line, removing property from a Special Flood Hazard Area, 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. * ''Mine survey, 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 ''Structural encroachment, encroachment'', building setback restrictions and shows nearby flood zones. In many places a mortgage survey is a precondition for a mortgage loan. * ''Photogrammetry, Photographic control survey'': A survey that creates reference marks visible from the air to allow Aerial photography, aerial photographs to be Orthophoto, 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 that measures the elevation of points on a particular piece of land, and presents them as contour lines on a plot. * ''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 drawing, architectural drawings and blueprints to locate or place building structures. * ''Underwater survey'': a survey of an underwater site, object, or area.

## Plane and 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'' 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.

# 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 transport, pipelines, retaining walls, bridges, and buildings. They establish the boundaries of legal descriptions and political divisions. They also provide advice and data for ''Geographic information system, geographical information systems'' (GIS) that record land features and boundaries. Surveyors must have a thorough knowledge of algebra, basic calculus,
geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related with distance, shape, size, and relative position of figures. A mat ...

, and
trigonometry Trigonometry (from ', "triangle" and ', "measure") is a branch of that studies relationships between side lengths and s of s. The field emerged in the during the 3rd century BC from applications of to . The Greeks focused on the , while ...

. They must also know the laws that deal with surveys, real property, 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 chains. 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 Surveyor, chartered surveyors'' 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 Principal (commercial law), principals of surveying firms hold this status. Related professions include cartographers, hydrographers, geodesists, photogrammetrists, and topographers, as well as civil engineers and geomatics engineers.

## 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 letters, post nominal, 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 monuments 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 networks. 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 (abbreviation, 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 establish ...
(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.

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 (BLM) conducts most cadastral surveys in the United States. They consult with US Forest Service, Forest Service, National Park Service, US Army Corps of Engineers, Army Corps of Engineers, Bureau of Indian Affairs, US Fish and Wildlife Service, Fish and Wildlife Service, US Bureau of Reclamation, Bureau of Reclamation, and others. The BLM used to be known as the General Land Office (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 1785 ...

(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

Three of the four U.S. Presidents on Mount Rushmore were land surveyors. George Washington, Thomas Jefferson, and Abraham Lincoln Surveying in early America, surveyed colonial or frontier territories prior to serving office. David T. Abercrombie practiced land surveying before starting an outfitter store of excursion goods. The business would later turn into Abercrombie & Fitch lifestyle clothing store. Percy Fawcett, Percy Harrison Fawcett was a British surveyor that explored the jungles of South America attempting to find the Lost City of Z. His biography and expeditions were recounted in the book The Lost City of Z (book), ''The Lost City of Z'' and were later adapted on The Lost City of Z (film), film screen. Inō Tadataka produced the first map of Japan using modern surveying techniques starting in 1800, at the age of 55.

* * * * * * * *

# References

* * Keay J (2000), ''The Great Arc: The Dramatic Tale of How India was Mapped and Mount Everest, Everest 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, . * Public Land Survey System Foundation (2009) ''Manual of Surveying Instructions For the Survey of the Public Lands of the United States''
www.blmsurveymanual.org

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.
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)