Surveying

# Surveying

Overview
Public Land Survey System
The Public Land Survey System is a method used in the United States to survey and identify land parcels, particularly for titles and deeds of rural, wild or undeveloped land. Its basic units of area are the township and section. It is sometimes referred to as the rectangular survey system,...

Discussion

Recent Discussions
Encyclopedia
Public Land Survey System
The Public Land Survey System is a method used in the United States to survey and identify land parcels, particularly for titles and deeds of rural, wild or undeveloped land. Its basic units of area are the township and section. It is sometimes referred to as the rectangular survey system,...

Surveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them. These points are usually on the surface of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

, and they are often used to establish land maps
MAPS
Maps is the plural of map, a visual representation of an area.As an acronym, MAPS may refer to:* Mail Abuse Prevention System, an organisation that provides anti-spam support...

and boundaries for ownership
Ownership
Ownership is the state or fact of exclusive rights and control over property, which may be an object, land/real estate or intellectual property. Ownership involves multiple rights, collectively referred to as title, which may be separated and held by different parties. The concept of ownership has...

or governmental purposes.

To accomplish their objective, surveyors use elements of mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

(geometry
Geometry
Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....

and trigonometry
Trigonometry
Trigonometry is a branch of mathematics that studies triangles and the relationships between their sides and the angles between these sides. Trigonometry defines the trigonometric functions, which describe those relationships and have applicability to cyclical phenomena, such as waves...

), physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

, engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

and law
Law
Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

.

An alternative definition, per the American Congress on Surveying and Mapping
American Congress on Surveying and Mapping
The American Congress on Surveying and Mapping is an international professional association representing the interests of those engaged in measuring and communicating spatial data relating to the Earth's surface...

(ACSM), is the science and art of making all essential measurements to determine the relative position of points and/or physical and cultural details above, on, or beneath the surface of the Earth, and to depict them in a usable form, or to establish the position of points and/or details.

Furthermore, as alluded to above, a particular type of surveying known as "land surveying" (also per ACSM) is the detailed study or inspection, as by gathering information through observations, measurements in the field, questionnaires, or research of legal instruments, and data analysis in the support of planning, designing, and establishing of property boundaries. It involves the re-establishment of cadastral survey
A cadastre , using a cadastral survey or cadastral map, is a comprehensive register of the metes-and-bounds real property of a country...

s and land boundaries based on documents of record and historical evidence, as well as certifying surveys (as required by statute or local ordinance) of subdivision plats/maps, registered land surveys, judicial surveys, and space delineation. Land surveying can include associated services such as mapping and related data accumulation, construction layout surveys, precision measurements of length, angle, elevation, area, and volume, as well as horizontal and vertical control surveys, and the analysis and utilization of land survey data.

Surveying has been an essential element in the development of the human environment since the beginning of recorded history (about 5,000 years ago). It is required in the planning and execution of nearly every form of construction
Construction
In the fields of architecture and civil engineering, construction is a process that consists of the building or assembling of infrastructure. Far from being a single activity, large scale construction is a feat of human multitasking...

. Its most familiar modern uses are in the fields of transport
Transport
Transport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...

, building
Building
In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...

and construction, communication
Communication
Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...

s, mapping, and the definition of legal boundaries for land ownership.

## History of surveying

Surveying techniques have existed throughout much of recorded history. In ancient Egypt
Ancient Egypt
Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

, when the Nile River overflowed its banks and washed out farm
Farm
A farm is an area of land, or, for aquaculture, lake, river or sea, including various structures, devoted primarily to the practice of producing and managing food , fibres and, increasingly, fuel. It is the basic production facility in food production. Farms may be owned and operated by a single...

boundaries, boundaries were re-established by a rope stretcher
Rope stretcher
In ancient Egypt rope stretchers were surveyors who measured property demarcations and foundations using knotted cords which they stretched in order to take the sag out of the rope. When performed by kings during the initial stage of temple building the Stretching of the Rope was probably a...

, or surveyor, through the application of simple geometry
Geometry
Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....

. The
nearly perfect squareness and north-south orientation of the Great Pyramid of Giza
Great Pyramid of Giza
The Great Pyramid of Giza is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact...

, built c. 2700 BC, affirm the Egyptians' command of surveying.

A brief history of surveying:
• The Egyptian land register (3000 BC).
• A recent reassessment of Stonehenge
Stonehenge
Stonehenge is a prehistoric monument located in the English county of Wiltshire, about west of Amesbury and north of Salisbury. One of the most famous sites in the world, Stonehenge is composed of a circular setting of large standing stones set within earthworks...

(c. 2500 BC) suggests that the monument was set out by prehistoric surveyors using peg and rope geometry.
• The Groma surveying
Groma surveying
The Groma or gruma was the principal Roman surveying instrument. It comprised a vertical staff with horizontal cross pieces mounted at right-angles on a bracket. Each cross piece had a plumb line hanging vertically at each end...

instrument originated in Mesopotamia
Mesopotamia
Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

(early 1st millennium BC).
• Under the Romans, land surveyors were established as a profession, and they established the basic measurements under which the Roman Empire was divided, such as a tax register of conquered lands (300 AD).
• The rise of the Caliphate
Caliphate
The term caliphate, "dominion of a caliph " , refers to the first system of government established in Islam and represented the political unity of the Muslim Ummah...

led to extensive surveying throughout the Arab Empire. Arabic surveyors
Inventions in the Islamic world
A number of inventions were developed in the medieval Islamic world, a geopolitical region that has at various times extended from Spain and Africa in the west to the Indian subcontinent in the east. The inventions listed here were developed during the medieval Islamic world, which covers the...

invented a variety of specialized instruments for surveying, including:
• Instruments for accurate leveling: A wooden board with a plumb line and two hooks, an equilateral triangle with a plumb line and two hooks, and a reed
Reed level
A reed level is an Arabic invention for determining level for the purpose of construction. A hole is put through a long straight reed and water is poured into the center. When the flow out of both sides is equal, the reed is level. The device serves the same purpose as a spirit level....

level.
An alidade is a device that allows one to sight a distant object and use the line of sight to perform a task. This task can be, for example, to draw a line on a plane table in the direction of the object or to measure the angle to the object from some reference point...

, used for accurate alignment.
• A surveying astrolabe
Astrolabe
An astrolabe is an elaborate inclinometer, historically used by astronomers, navigators, and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon, planets, and stars, determining local time given local latitude and longitude, surveying, triangulation, and to...

, used for alignment, measuring angles, triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...

, finding the width of a river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

, and the distance between two points separated by an impassable obstruction.
• In England, The Domesday Book
Domesday Book
Domesday Book , now held at The National Archives, Kew, Richmond upon Thames in South West London, is the record of the great survey of much of England and parts of Wales completed in 1086...

by William the Conqueror (1086)
• covered all England
• contained names of the land owners, area, land quality, and specific information of the area's content and inhabitants.
• did not include maps showing exact locations

In the 18th century in Europe triangulation was used to build a hierarchy of networks to allow point positioning within a country. Highest in the hierarchy were triangulation networks. These were densified into networks of traverses
Traverse (surveying)
Traverse is a method in the field of surveying to establish control networks. It is also used in geodesy. Traverse networks involve placing survey stations along a line or path of travel, and then using the previously surveyed points as a base for observing the next point...

(polygons), into which local mapping surveying measurements, usually with measuring tape, corner prism and the familiar red and white poles, are tied. For example, in the late 1780s, a team from the Ordnance Survey
Ordnance Survey
Ordnance Survey , an executive agency and non-ministerial government department of the Government of the United Kingdom, is the national mapping agency for Great Britain, producing maps of Great Britain , and one of the world's largest producers of maps.The name reflects its creation together with...

of Great Britain, originally under General William Roy
William Roy
Major-General William Roy FRS 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 Great Britain....

began the Principal Triangulation of Britain using the specially built Ramsden theodolite
Ramsden theodolite
The Ramsden theodolite is a large theodolite that was specially constructed for use in the first Ordnance Survey of Southern Britain. It was also known as the Great or 36 inch theodolite....

. Large scale surveys are known as geodetic
Geodesy
Geodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...

surveys.
A cadastre , using a cadastral survey or cadastral map, is a comprehensive register of the metes-and-bounds real property of a country...

was created in 1808
• founded by Napoleon I (Bonaparte)
• contained numbers of the parcels of land (or just land), land usage, names etc., and value of the land
• 100 million parcels of land, triangle survey, measurable survey, map scale: 1:2500 and 1:1250
• spread fast around Europe, but faced problems especially in Mediterranean countries, Balkan, and Eastern Europe due to cadastre upkeep costs and troubles.

A cadastre loses its value if register and maps are not constantly updated.
Because of the fundamental value of land and real estate to the local and global economy, land surveying was one of the first professions to require Professional Licensure
Licensure
Licensure refers to the granting of a license, which gives a "permission to practice." Such licenses are usually issued in order to regulate some activity that is deemed to be dangerous or a threat to the person or the public or which involves a high level of specialized skill...

. In many jurisdictions, the land surveyors license was the first Professional Licensure issued by the state, province, or federal government.

## Surveying techniques

Historically, distance
Distance
Distance is a numerical description of how far apart objects are. In physics or everyday discussion, distance may refer to a physical length, or an estimation based on other criteria . In mathematics, a distance function or metric is a generalization of the concept of physical distance...

s were measured using a variety of means, such as with chains having links of a known length, for instance a Gunter's chain
Gunter's chain
Gunter's chain is a measuring device used for land survey. It was designed and introduced in 1620 by English clergyman and mathematician Edmund Gunter long before the development of the theodolite and other more sophisticated equipment, enabling plots of land to be accurately surveyed and plotted,...

, or measuring tapes made of steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

or invar
Invar
Invar, also known generically as FeNi36 , is a nickel steel alloy notable for its uniquely low coefficient of thermal expansion . The name, Invar, comes from the word invariable, referring to its lack of expansion or contraction with temperature changes.It was invented in 1896 by Swiss scientist...

. To measure horizontal distances, these chains or tapes were pulled taut according to temperature, to reduce sagging and slack. Additionally, attempts to hold the measuring instrument level would be made. In instances of 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.

Historically, horizontal angles were measured using a compass
Compass
A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...

, which would provide a magnetic bearing, from which deflections could be measured. This type of instrument was later improved, with more carefully scribed discs providing better angular resolution, as well as through mounting telescopes with reticles for more-precise sighting atop the disc (see theodolite
Theodolite
A theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for specialized purposes in fields like metrology and rocket launch technology...

). Additionally, levels and calibrated circles allowing measurement of vertical angles were added, along with vernier
Vernier scale
A vernier scale is an additional scale which allows a distance or angle measurement to be read more precisely than directly reading a uniformly-divided straight or circular measurement scale...

s for measurement to a fraction of a degree—such as with a turn-of-the-century transit.

The simplest method for measuring height is with an altimeter
Altimeter
An altimeter 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 underwater.-Pressure altimeter:...

— basically a barometer
Barometer
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather...

— using air pressure as an indication of height. But surveying requires greater precision. A variety of means, such as precise levels (also known as differential leveling), have been developed to do this. With precise leveling, a series of measurements between two points are taken using an instrument and a measuring rod. Differentials in height between the measurements are added and subtracted in a series to derive the net difference in elevation between the two endpoints of the series. With the advent of the Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

(GPS), elevation can also be derived with sophisticated satellite receivers, but usually with somewhat less accuracy than with traditional precise leveling. However, the accuracies may be similar if the traditional leveling would have to be run over a long distance.

Triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...

is another method of horizontal location made almost obsolete by GPS. With the triangulation method, distances, elevations and directions between objects at great distance from one another can be determined. 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. Then the height, 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 for this work, and angles between objects were measured repeatedly for increased accuracy.

Turning is a term used when referring to moving the level to take a elevation shot in a different location. When land surveying, there may be trees or other obstructions blocking the view from the level gun to the level rod. In order to "turn" the level gun, you mush first take a shot on the rod from your current location and record the elevation. Keeping the level rod in exactly the same location and elevation you may move the level gun to a different location where the level rod is still visible. Record the new elevation seen from the new location of the level rod and use the difference in elevations to find the new elevation of the level gun. Turning is not only used when there are obstructions in the way, but also when drastically changing elevations. You can turn up or down in elevation but the gun must always be at a higher elevation than the base of the rod. A level rod can usually be raised up to 25 feet high which enables the gun to be set much higher. However, if the gun is lower than the base of the rod, you will not be able to take a shot because the rod cannot be lowered beyond the ground elevation.

## Surveying equipment

As late as the 1990s, the basic tools used in planar surveying were a tape measure for determining shorter distances, a level to determine height or elevation differences, and a theodolite
Theodolite
A theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for specialized purposes in fields like metrology and rocket launch technology...

, set on a tripod
Tripod (surveying)
A surveyor's tripod is a device used to support any one of a number of surveying instruments, such as theodolites, total stations, levels or transits.- History :...

, to measure angles (horizontal and vertical), combined with the process of triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...

. Starting from a position with known location and elevation, the distance and angles to the unknown point are measured.

A more modern instrument is a total station
Total station
A total station is an electronic/optical instrument used in modern surveying. The total station is an electronic theodolite integrated with an electronic distance meter to read slope distances from the instrument to a particular point....

, which is a theodolite with an electronic distance measurement device (EDM). A total station can also be used for leveling when set to the horizontal plane. Since their introduction, total stations have made the technological shift from being optical-mechanical devices to being fully electronic.

Modern top-of-the-line total stations no longer require a reflector or prism (used to return the light pulses used for distancing) to return distance measurements, are fully robotic, and can even e-mail point data to the office computer and connect to satellite positioning systems, such as a Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

. Though real-time kinematic GPS systems have increased the speed of surveying, they are still horizontally accurate to only about 20 mm and vertically accurate to about 30–40 mm.

Total stations are still used widely, along with other types of surveying instruments. However, GPS systems do not work well in areas with dense tree cover or constructions. One-person robotic-guided total stations allow surveyors to gather precise measurements without extra workers to look through and turn the telescope or record data. A faster but expensive way to measure large areas (not details, and no obstacles) is with a helicopter, equipped with a laser scanner, combined with a GPS to determine the position and elevation of the helicopter. To increase precision, surveyors place beacons on the ground (about 20 km (12 mi) apart). This method reaches precisions between 5–40 cm (depending on flight height).

## Types of surveys and applicability

• ALTA/ACSM Survey: a surveying standard jointly proposed by the American Land Title Association
American Land Title Association
The American Land Title Association or ALTA, is a national trade association representing the interests of the abstract of title and title insurance industries...

and the American Congress on Surveying and Mapping
American Congress on Surveying and Mapping
The American Congress on Surveying and Mapping is an international professional association representing the interests of those engaged in measuring and communicating spatial data relating to the Earth's surface...

that incorporates elements of the boundary survey, mortgage survey, and topographic survey.
• Archaeological survey: used to accurately assess the relationship of archaeological sites in a landscape or to accurately record finds on an archaeological site.
• As-built survey: a survey carried out during or immediately after a construction project for record, completion evaluation and payment purposes. An as-built survey also known as a 'works as executed survey' documents the location of the recently constructed elements that are subject to completion evaluation. As built surveys are typically presented in red or redline and overlayed over existing design plans for direct comparison with design information.
• Bathymetric survey
Bathymetry
Bathymetry is the study of underwater depth of lake or ocean floors. In other words, bathymetry is the underwater equivalent to hypsometry. The name comes from Greek βαθύς , "deep", and μέτρον , "measure"...

:
a survey carried out to map the topography and features of the bed of an ocean, lake, river or other body of water.
• Boundary survey: a survey that establishes boundaries of a parcel using its legal description
Land description
A Land description consists 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 include a written description of the property.- Canada...

, which typically involves the setting or restoration of monuments or markers at the corners or along the lines of the parcel, often in the form of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

rods, pipes
Pipe (material)
A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases , slurries, powders, masses of small solids...

, or concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

monuments in the ground, or nails set in concrete or asphalt.
• Deformation survey
Deformation monitoring
Deformation monitoring is the systematic measurement and tracking of the alteration in the shape or dimensions of an object as a result of stresses induced by applied loads...

:
a survey to determine if a structure or object is changing shape or moving. The three-dimensional positions of specific points on an object are determined, a period of time is allowed to pass, these positions are then re-measured and calculated, and a comparison between the two sets of positions is made.
• Engineering surveys: those surveys associated with the engineering design (topographic, layout and as-built) often requiring geodetic computations beyond normal civil engineering practise.
• 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.
• Geological survey: generic term for a survey conducted for the purpose of recording the geologically significant features of the area under investigation. .
• Hydrographic survey: a survey conducted with the purpose of mapping the coastline and seabed for navigation, engineering, or resource management purposes.
• 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 "as built survey"
• Mortgage survey or physical survey: a simple survey that delineates land boundaries and building locations. In many places a mortgage survey is required by lending institutions as a precondition for a mortgage loan.
• Soil survey, or soil mapping
Soil survey
Soil survey, or soil mapping, is the process of classifying soil types and other soil properties in a given area and geo-encoding such information. It applies the principles of soil science, and draws heavily from geomorphology, theories of soil formation, physical geography, and analysis of...

, is the process of determining the soil types or other properties of the soil cover over a landscape, and mapping them for others to understand and use.
• Structural survey: a detailed inspection to report upon the physical condition and structural stability of a building or other structure and to highlight any work needed to maintain it in good repair.
• Tape survey: this type of survey is the most basic and inexpensive type of land survey. Popular in the middle part of the 20th century, tape surveys while being accurate for distance lack substantially in their accuracy of measuring angle and bearing. Standards that are practiced by professional land surveyors.
• Topographic survey: a survey that measures the elevation of points on a particular piece of land, and presents them as contour line
Contour line
A contour line of a function of two variables is a curve along which the function has a constant value. In cartography, a contour line joins points of equal elevation above a given level, such as mean sea level...

s on a plot.

## Surveying as a career

The basic principles of surveying have changed little over the ages, but the tools used by surveyors have evolved tremendously. Engineering, especially civil engineering
Civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...

, depends heavily on surveyors.

Whenever there are roads, railways, reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

, dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

s, retaining wall
Retaining wall
Retaining walls are built in order to hold back earth which would otherwise move downwards. Their purpose is to stabilize slopes and provide useful areas at different elevations, e.g...

s, bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

s or residential areas to be built, surveyors are involved. They establish the boundaries of legal descriptions and the boundaries of various lines of political divisions. They also provide advice and data for geographical information system
Geographic Information System
A geographic information system, geographical information science, or geospatial information studies is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data...

s
(GIS), computer databases that contain data on land features and boundaries.

Surveyors must have a thorough knowledge of algebra
Algebra
Algebra is the branch of mathematics concerning the study of the rules of operations and relations, and the constructions and concepts arising from them, including terms, polynomials, equations and algebraic structures...

, basic calculus
Calculus
Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...

, geometry
Geometry
Geometry arose as the field of knowledge dealing with spatial relationships. Geometry was one of the two fields of pre-modern mathematics, the other being the study of numbers ....

, and trigonometry
Trigonometry
Trigonometry is a branch of mathematics that studies triangles and the relationships between their sides and the angles between these sides. Trigonometry defines the trigonometric functions, which describe those relationships and have applicability to cyclical phenomena, such as waves...

. They must also know the laws that deal with survey
A cadastre , using a cadastral survey or cadastral map, is a comprehensive register of the metes-and-bounds real property of a country...

s, property
Property
Property is any physical or intangible entity that is owned by a person or jointly by a group of people or a legal entity like a corporation...

, and contract
Contract
A contract is an agreement entered into by two parties or more with the intention of creating a legal obligation, which may have elements in writing. Contracts can be made orally. The remedy for breach of contract can be "damages" or compensation of money. In equity, the remedy can be specific...

s.

In addition, they must be able to use delicate instruments with accuracy and precision
Accuracy and precision
In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...

. In the United States, surveyors and civil engineers use units of feet wherein a survey foot is broken down into 10ths and 100ths. Many deed descriptions requiring distance calls 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 such as this will vary from project to project, in the field and day to day usage beyond a 100th of a foot is often impractical.

In most of the United States, surveying is recognized as a distinct profession apart from engineering. Licensing requirements
Professional Engineer
Regulation of the engineering profession is established by various jurisdictions of the world to protect the safety, well-being and other interests of the general public, and to define the licensure process through which an engineer becomes authorized to provide professional services to the...

vary by state, but they generally have components of education, experience and examinations. In the past, experience gained through an apprenticeship
Apprenticeship
Apprenticeship is a system of training a new generation of practitioners of a skill. Apprentices or protégés build their careers from apprenticeships...

, together with passing a series of state-administered examinations, was required to attain licensure. Now, most states insist upon basic qualification of a degree in surveying, plus experience and examination requirements.

The licensing process typically follows two phases. First, upon graduation, the candidate may be eligible to take the Fundamentals of Land Surveying exam, to be certified upon passing and meeting all other requirements as a surveyor in training (SIT). Upon being certified as an SIT, the candidate then needs to gain additional experience to become eligible for the second phase. That typically consists of the Principles and Practice of Land Surveying exam along with a state-specific examination.

Licensed surveyors usually denote themselves with the letters P.S. (professional surveyor), L.S. (land surveyor), P.L.S. (professional land surveyor), R.L.S. (registered land surveyor), R.P.L.S. (Registered Professional Land Surveyor), or P.S.M. (professional surveyor and mapper) following their names, depending upon the dictates of their particular jurisdiction of registration.

In Canada, land Surveyors are registered to work in their respective province. The designation for a land surveyor breaks down by province, but follows the rule whereby the first letter indicates the province, followed by L.S. There is also a designation as a C.L.S. or Canada lands surveyor, who has the authority to work on Canada Lands, which include Indian Reserves, National Parks, the three territories and offshore lands.

In many Commonwealth countries, the term Chartered Land Surveyor is used for someone holding a professional license to conduct surveys.

A licensed land surveyor is typically required to sign and seal all plans, the format of which is dictated by their state jurisdiction, which shows their name and registration number. In many states, when setting boundary corners land surveyors are also required to place survey monuments bearing their registration numbers, typically in the form of capped iron rods, concrete monuments, or nails with washers.

### Building surveying

Building surveying emerged in the 1970s as a profession in the United Kingdom by a group of technically minded General Practice Surveyors. Building surveying is a recognised profession in Britain, Ireland, Australia and Hong Kong. In Australia in particular, due to risk mitigation and limitation factors, the employment of surveyors at all levels of the construction industry is widespread. There are still many countries where it is not widely recognized as a profession.

Building Surveyors are trained to some extent in all aspects of property but with specific training in Building Pathology, as such they have a wide understanding of the end implications of decisions taken by more specific professions and trades during the realisation process, thus making them ideal Project and Property Managers on the client side.

Services that building surveyors undertake are broad but can include:
• Construction design and building works
• Project management and monitoring
• Insurance assessment and claims assistance
• Defect investigation and maintenance advice
• Building surveys and measured surveys
• Handling planning applications
• Building inspection to ensure compliance with building regulations
• Pre-acquisition surveys
• Negotiating dilapidations claims

Building surveyors also advise on many aspects of construction including:
• design
• cost
• maintenance
• sustainability
• repair
• refurbishment
• restoration and preservation of buildings and monuments

Clients of a building surveyor can be the government agencies, businesses and individuals. Surveyors work closely with architects, planners, quantity surveyors, engineers, homeowners and tenants groups. A building surveyor may be called to act as an expert witness
Expert witness
An expert witness, professional witness or judicial expert is a witness, who by virtue of education, training, skill, or experience, is believed to have expertise and specialised knowledge in a particular subject beyond that of the average person, sufficient that others may officially and legally...

. It is usual for building surveyors to earn a college degree before undertaking structured training to become a member of a professional organisation.

With the enlargement of the European community, the profession of the building surveyor is becoming more widely known in other European states, particularly France, where many English-speaking people buy second homes.

Lidar Surveying – Three-dimensional laser scanning provides high definition surveying for architectural, as-built, and engineering surveys. Recent technological advances make it the most cost-effective and time-sensitive solution for providing the highest level of detail available for interior and exterior building work.

## Land surveyor

The job of the land surveyor is to find and mark certain locations on land. A typical location of interest, for example, is the boundary of a person's property. That boundary is described in legal documents and the land surveyor follows that description and locates the boundary on the physical land and marks it, so the owner knows what land he can legally use. As an example, such a legal description may refer to a point as being 120.25 feet south of some existing marker. The land surveyor in that case would find the existing marker and use measuring instruments to find the point 120.25 feet south of that, and place a new marker at that location. These markers are called monuments.

Over time, development, vandalism, and acts of nature often wreak havoc on monumentation, so the land surveyor is often forced to consider other evidence such as fence locations, woodlines, monuments on neighboring property, recollections of people, and other evidence.

Reference monumentation refers to actual physical points on the ground that define location of boundary lines that divide neighboring parcels as well as their respective corners. Also called survey control, they are most often 1/2" or 5/8" iron rebar rods or pipes placed at 18" minimum depth. These rods and/or pipes usually have an affixed plastic cap over the top bearing the responsible surveyors' name and license number. In addition to rods and pipes, surveyors often use 4x4" concrete posts at corners of large parcels or anywhere that would require more stability (e.g. beach sand). They place them three feet deep. In places where there is asphalt or concrete, it is common to place nails or aluminum alloy caps to re-establish boundary corners. Marks are meant to be durable, stable, and as "permanent" as possible. The aim is to provide sufficient marks so some marks will remain for future re-establishment of boundaries. The material and marking used on monuments placed to mark boundary corners are often subject to state laws.

In the United States, cadastral surveys are typically conducted by the federal government, specifically through the Cadastral Surveys branch of the Bureau of Land Management
Bureau of Land Management
The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...

(BLM), formerly the General Land Office
General Land Office
The General Land Office 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 of the Treasury...

(GLO).
They consult with USFS, Park Service, Corps of Engineers, BIA, Fish and Wildlife Service, Bureau of Reclamation, etc. In states that have been organized per the Public Land Survey System
Public Land Survey System
The Public Land Survey System is a method used in the United States to survey and identify land parcels, particularly for titles and deeds of rural, wild or undeveloped land. Its basic units of area are the township and section. It is sometimes referred to as the rectangular survey system,...

(PLSS), surveyors carry out BLM Cadastral Surveys in accordance with that system.

A common use of a survey is to determine a legal property boundary. The first stage in such a survey is to research relevant title records such as deeds, survey monumentation (marks on the ground), and any public or private records that provide relevant data.

In order to properly establish the position for survey markers, the surveyor must then take measurements. To do this, the surveyor usually places a total station
Total station
A total station is an electronic/optical instrument used in modern surveying. The total station is an electronic theodolite integrated with an electronic distance meter to read slope distances from the instrument to a particular point....

over various points on the ground and records distances taken with the EDM
EDM
EDM may also refer to:In information technology:* Electronic direct marketing, another term for E-mail marketing* Electronic Direct Mail*Electronic document management, the tracking and storage of electronic documents...

.

The surveyor analyses the data and makes comparisons with existing records to determine evidence that can be used to establish boundary positions. The surveyor calculates the bearing and distance of lines between the boundary corners and total station positions and uses them to set out and mark the corners in the field. He may check measurements by measuring directly between places using a flexible tape.

### The art of surveying

Many properties have considerable problems with regards to improper bounding, miscalculations in past surveys, titles, easements, and wildlife crossings. Also many properties are created from multiple divisions of a larger piece over the course of years, and with every additional division the risk of miscalculation increases. The result can be abutting properties not coinciding with adjacent parcels, resulting in hiatuses (gaps) and overlaps. The art plays a role when a surveyor must solve a puzzle using pieces that do not exactly fit together. In these cases, the solution is based upon the surveyor's research and interpretation, along with established procedures for resolving discrepancies.