A surveyor at work with a retroreflector used for distance measurement
Surveying or land surveying is the technique, profession, 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, locations, such as building corners 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 geometry, trigonometry, regression
analysis, physics, engineering, metrology, programming languages, and
the law. They use equipment, such as total stations, robotic total
GPS receivers, retroreflectors, 3D scanners, radios,
handheld tablets, digital levels, subsurface locators, drones, GIS,
and surveying software.
Surveying has been an element in the development of the human
environment since the beginning of recorded history. 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. It is an important tool for research in
many other scientific disciplines.
2.1 Ancient surveying
2.2 Modern surveying
2.3 20th century
2.4 21st century
4.4 Determining position
4.5 Reference networks
4.5.1 Datum and coordinate systems
4.6 Errors and accuracy
5 Types of surveys
5.1 Plane and geodetic surveying
6 The surveying profession
6.3 Building surveying
6.4 Cadastral surveying
6.5 Noteworthy Surveyors
7 See also
9 Further reading
10 External links
American Congress on Surveying and Mapping (ACSM), defines
surveying as the science and art of making all essential measurements
to determine the relative position of points 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 or
Also per ACSM, the type of surveying known as "land surveying" 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 surveys 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 or 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.
International Federation of Surveyors
International Federation of Surveyors defines the function of
A surveyor is a professional person with the academic qualifications
and technical expertise to conduct one, or more, of the following
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.
Cadastre § History,
Cartography § History, and
Topographic mapping § History
A plumb rule from the book Cassells' Carpentry and Joinery
Surveying has occurred since humans built the first large structures.
In ancient Egypt, a rope stretcher would use simple geometry to
re-establish boundaries after the annual floods of the Nile River. The
almost perfect squareness and north-south orientation of the Great
Pyramid of Giza, built c. 2700 BC, affirm the Egyptians' command of
surveying. The Groma instrument originated in
Mesopotamia (early 1st
millennium BC). The prehistoric monument at
Stonehenge (c. 2500 BC)
was set out by prehistoric surveyors using peg and rope geometry.
Liu Hui described ways of measuring distant objects
in his work
Haidao Suanjing 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.
In medieval Europe, beating the bounds 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.
William the Conqueror
William the Conqueror commissioned the
Domesday Book 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
Table of Surveying, 1728 Cyclopaedia
Abel Foullon described a plane table in 1551, but it is thought that
the instrument was in use earlier as his description is of a developed
Gunter's chain was introduced in 1620 by English mathematician Edmund
Gunter. It enabled plots of land to be accurately surveyed and plotted
for legal and commercial purposes.
Leonard Digges described a
Theodolite that measured horizontal angles
in his book A geometric practice named Pantometria (1571). Joshua
Habermel (de: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.
In the 18th century, modern techniques and instruments for surveying
began to be used.
Jesse Ramsden introduced the first precision
theodolite in 1787. It was an instrument for measuring angles in the
horizontal and vertical planes. He created his great theodolite using
an accurate dividing engine of his own design. Ramsden's theodolite
represented a great step forward in the instrument's accuracy. William
Gascoigne invented an instrument that used a telescope with an
installed crosshair as a target device, in 1640.
James Watt developed
an optical meter for the measuring of distance in 1771; it measured
the parallactic angle from which the distance to a point could be
Willebrord Snellius (a.k.a. Snel van Royen)
introduced the modern systematic use of triangulation. In 1615 he
surveyed the distance from
Alkmaar to Breda, approximately 72 miles
(116,1 kilometres). 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 resection, 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 and his son
César undertook the first triangulation of France. They included a
re-surveying of the meridian arc, leading to the publication in 1745
of the first map of
France constructed on rigorous principles. By this
time, triangulation methods were by then well established for local
A map of
India showing the Great Trigonometrical Survey, produced in
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's
Ordnance Survey of Great Britain began the
Triangulation of Britain. The first
Ramsden theodolite was
built for this survey. The survey was finally completed in 1853. The
Great Trigonometric Survey
Great Trigonometric Survey 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 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 profession developed more
accurate instruments to aid its work. Industrial infrastructure
projects used surveyors to lay out canals, roads and rail.
In the US, the
Land Ordinance of 1785
Land Ordinance of 1785 created the Public Land Survey
System. 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
Napoleon Bonaparte founded continental Europe's first cadastre in
1808. This gathered data on the number of parcels of land, their
value, land usage, and names. This system soon spread around Europe.
A railroad surveying party at Russel's Tank,
Arizona in the 1860s
Robert Torrens introduced the
Torrens system 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.
A German engineer surveying during the First World War, 1918
At the beginning of the century surveyors had improved the older
chains and ropes, but still faced the problem of accurate measurement
of long distances. Dr Trevor Lloyd Wadley developed the Tellurometer
during the 1950s. It measures long distances using two microwave
transmitter/receivers. During the late 1950s Geodimeter introduced
electronic distance measurement (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 stations. 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 TRANSIT system.
The first successful launch took place in 1960. The system's main
purpose was to provide position information to Polaris missile
submarines. Surveyors found they could use field receivers to
determine the location of a point. Sparse satellite cover and large
equipment made observations laborious, and inaccurate. The main use
was establishing benchmarks in remote locations.
The US Air Force launched the first prototype satellites of the Global
Positioning System (GPS) in 1978.
GPS used a larger constellation of
satellites and improved signal transmission to provide more accuracy.
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 (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.
The theodolite, total station, and RTK
GPS 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 for
topographical surveys. UAV technology along with photogrammetric image
processing is also appearing.
Further information: List of surveying instruments
Surveying equipment. Clockwise from upper left: optical theodolite,
robotic total station, RTK
GPS base station, optical level.
The main surveying instruments in use around the world are the
theodolite, measuring tape, total station, 3D scanners, GPS/GNSS,
level and rod. Most instruments screw onto a tripod 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 is a form of theodolite that uses a gyroscope to
orient itself in the absence of reference marks. It is used in
The total station 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. Real time kinematic
GPS systems have increased the
speed of surveying, but they are still only horizontally accurate to
about 20 mm and vertically to 30–40 mm.
GPS surveying differs from other
GPS uses in the equipment and methods
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
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
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 on the ground (about
20 km (12 mi) 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.
Land surveyors, construction professionals and civil engineers using
total station, GPS, 3D scanners and other collector data use Land
Surveying Software to increase efficiency, accuracy and productivity.
Surveying Software is a staple of contemporary land
A standard Brunton Geo compass, still used commonly today by
geographers, geologists and surveyors for field-based measurements
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.
Example of modern equipment for surveying (
Field-Map technology): GPS,
laser rangefinder and field computer allows surveying as well as
cartography (creation of map in real-time) and field data collection.
Before EDM devices, distances were measured using a variety of means.
These included chains with links of a known length such as a Gunter's
chain, or measuring tapes made of steel or invar. 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.
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
Historically, horizontal angles were measured by using a 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). Levels
and calibrated circles allowed measurement of vertical angles.
Verniers allowed measurement to a fraction of a degree, such as with a
The plane table provided a graphical method of recording and measuring
angles, which reduced the amount of mathematics required. In 1829
Francis Ronalds invented a reflecting instrument for recording angles
graphically by modifying the octant.
By observing the bearing from every vertex in a figure, a surveyor can
measure around the figure. The final observation will be between the
two points first observed, except with a 180° difference. This is
called a close. If the first and last bearings are different, this
shows the error in the survey, called the angular misclose. The
surveyor can use this information to prove that the work meets the
Main article: Levelling
Center for Operational Oceanographic Products and Services staff
member conducts tide station leveling in support of the US Army Corp
of Engineers in Richmond, Maine.
The simplest method for measuring height is with an
altimeter using air pressure to find 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 (GPS), elevation can be measured with satellite receivers.
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.
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 25 feet high, allowing
the level to be set much higher than the base of the rod.
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.
Main article: Geodetic network
A survey using traverse and offset measurements to record the location
of the shoreline shown in blue. Black dashed lines are traverse
measurements between reference points (black circles). The red lines
are offsets measured at right angles to the traverse lines.
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 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
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.
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 surveys 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
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
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. Errors can be
detected by comparing the results of the two measurements.
Once the surveyor has calculated the level of the errors in his work,
it is adjusted. This is the process of distributing the error between
all measurements. Each observation is weighted according to how much
of the total error it is likely to have caused and part of that error
is allocated to it in a proportional way. The most common methods of
adjustment are the Bowditch method, also known as the compass rule,
and the Principle of least squares method.
The surveyor must be able to distinguish between accuracy and
precision. 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 of surveys
Survey (other) and Survey (other)
§ Earth sciences
Local organisations or regulatory bodies class specializations of
surveying in different ways. Broad groups are:
As-built survey: a survey that documents the location of recently
constructed elements of a construction project. As-built surveys are
done for record, completion evaluation and payment purposes. An
as-built survey is also known as a 'works as executed survey'. As
built surveys are often presented in red or redline and laid over
existing plans for comparison with design information.
Cadastral or boundary surveying: a survey that establishes or
re-establishes boundaries of a parcel using a legal description. 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, pipes, or concrete monuments in the ground, or nails set in
concrete or asphalt. The ALTA/ACSM Land Title Survey is a standard
proposed by the
American Land Title Association
American Land Title Association and the American
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.
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
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
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.
LOMA survey: Survey to change base flood line, removing property from
a SFHA special flood hazard area.
Measured survey : a building survey to produce plans of the
building. such a survey may be conducted before renovation works, for
commercial purpose, or at end of the construction process.
Mining surveying: Mining surveying includes directing the digging of
mine shafts and galleries and the calculation of volume of rock. It
uses specialised techniques due to the restraints to survey geometry
such as vertical shafts and narrow passages.
Mortgage survey: A mortgage survey or physical survey is a simple
survey that delineates land boundaries and building locations. It
checks for encroachment, building setback restrictions and shows
nearby flood zones. In many places a mortgage survey is a precondition
for a mortgage loan.
Photographic control survey: A survey that creates reference marks
visible from the air to allow aerial photographs to be rectified.
Stakeout, layout or setout: an element of many other surveys where the
calculated or proposed position of an object is marked on the ground.
This can be temporary or permanent. This is an important component of
engineering and cadastral surveying.
Structural survey: a detailed inspection to report upon the physical
condition and structural stability of a building or structure. It
highlights any work needed to maintain it in good repair.
Subdivision: A boundary survey that splits a property into two or more
Topographic survey: a survey that measures the elevation of points on
a particular piece of land, and presents them as contour lines on a
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.
The surveying profession
See also: Geomatics,
Surveying In North America, and
The pundit cartographer
Nain Singh Rawat
Nain Singh Rawat (19th century) received a
Royal Geographical Society
Royal Geographical Society gold medal in 1876, for his efforts in
exploring the Himalayas for the British
An all-female surveying crew in Idaho, 1918
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, pipelines, retaining walls, bridges, and buildings. They
establish the boundaries of legal descriptions and political
divisions. They also provide advice and data for geographical
information systems (GIS) that record land features and boundaries.
Surveyors must have a thorough knowledge of algebra, basic calculus,
geometry, and trigonometry. 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 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 principals of surveying
firms hold this status.
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, 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
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 students with their professor at the Helsinki University of
Technology in the late 19th century
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 (Abbreviated FIG, for French: Fédération Internationale
des Géomètres). They represent the survey industry worldwide.
Main article: Building surveying § Profession
Most English-speaking countries consider building surveying a distinct
profession. They have their own professional associations and
licensing requirements. Building surveyors focus on investigating the
condition of buildings as well as legal compliance work.
Main article: Cadastral surveying
One of the primary roles of the land surveyor is to determine the
boundary of real property on the ground. The surveyor must determine
where the adjoining landowners wish to put the boundary. The boundary
is established in legal documents and plans prepared by attorneys,
engineers, and land surveyors. The surveyor then puts monuments on the
corners of the new boundary. They might also find or resurvey the
corners of the property monumented by prior surveys.
Cadastral land surveyors are licensed by governments. The cadastral
survey branch of the
Bureau of Land Management
Bureau of Land Management (BLM) conducts most
cadastral surveys in the United States. They consult with Forest
Service, National Park Service, Army Corps of Engineers, Bureau of
Indian Affairs, Fish and Wildlife Service, Bureau of Reclamation, and
others. The BLM used to be known as the
General Land Office
General Land Office (GLO).
In states organized per the
Public Land Survey System
Public Land Survey System (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.
Three of the four U.S. Presidents on
Mount Rushmore were land
surveyors. George Washington, Thomas Jefferson, and Abraham Lincoln
surveyed colonial or frontier territories prior to serving office.
David T. Abercrombie
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 Harrison Fawcett is 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
Lost City of Z publication and
later adapted on film screen.
International Federation of Surveyors
Prismatic compass (surveying)
Surveying in early America
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Public Land Survey System
Public Land Survey System Foundation (2009) Manual of Surveying
Instructions For the Survey of the Public Lands of the United States.
Look up surveying in Wiktionary, the free dictionary.
Library resources about
Resources in your library
Resources in other libraries
Wikimedia Commons has media related to Surveying.
Géomètres sans Frontières : Association de géometres pour
aide au développement. NGO Surveyors without borders (in French)
SurveyorConnect Community forum for Land Surveyors and Geomatics
Professionals offering peer-to-peer support, education, networking and
tales from the field.
The National Museum of
Surveying The Home of the National Museum of
Surveying in Springfield, Illinois
Land Surveyors United Support Network Global social support network
featuring surveyor forums, instructional videos, industry news and
support groups based on geolocation.
Natural Resources Canada –
Surveying Good overview of surveying with
references to construction surveys, cadastral surveys, photogrammetry
surveys, mining surveys, hydrographic surveys, route surveys, control
surveys and topographic surveys
Table of Surveying, 1728 Cyclopaedia
Triangulation The History Of
Surveying And Survey
NCEES National Council of Examiners for
Engineering and Surveying
NSPS National Society of Professional Surveyors (NSPS)
Ground Penetrating Radar FAQ Using Ground Penetrating Radar for Land
Survey Earth Global event and community of land surveyors.
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