Surveying is the technique of accurately determining positions and measurements of natural and man-made features on the Earth's surface. It involves measuring horizontal and vertical distances and angles. There are two main categories of surveying: plane surveying, which assumes a flat Earth, and geodetic surveying, which accounts for the Earth's curvature. The work of surveyors includes fieldwork to collect data, computations, mapping, and stakeouts. Surveying is used for applications such as boundary delineation, construction, and topographic mapping.
2. Surveying
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, commonly practiced by
licensed surveyors, and members of various building professions.
These points are usually on the surface of the Earth, and they are often used to
establish land maps and boundaries for ownership, locations (building corners,
surface location of subsurface features) or other governmentally required or civil
law purposes (property sales).
3. INTRODUCTION
Surveying is defined as “taking a general view of, by observation and
measurement determining the boundaries, size, position, quantity, condition,
value etc. of land, estates, building, farms mines etc. and finally presenting the
survey data in a suitable form”.
This covers the work of the valuation surveyor, the quantity surveyor, the building
surveyor, the mining surveyor and so forth, as well as the land surveyor.
Another school of thought define surveying “as the act of making measurement
of the relative position of natural and man made features on earth’s surface and
the presentation of this information either graphically or numerically”.
4. Introduction to Surveying
► Definition:
Surveying is the science and art of determining the relative positions of points
above, on, or beneath the earth’s surface and locating the points in the field.
5. Basic ideas
Surveying - the creation of a scale representation of the ground surface - is a basic
activity in many areas of Geography and environmental management.
A survey will be one of of two types:
Primary survey - to establish the position of objects
in three dimensions when no previous information
exists
Secondary survey - to add extra information to
existing data or to measure changes over an interval of
time.
6. The task of three dimensional position fixing is normally broken into two parts:
Determining plan position
Determining elevation
7. Basic ideas
Each of these determinations may be either:
absolute - made in terms of a fixed co-ordinate system
relative - made in terms of local co-ordinates which may later be converted to absolute co-
ordinates if required.
The majority of surveys carried out by survey of Pakistan are thus secondary
relative surveys as initially they were determiend by British government.
8. The work of the surveyor consists of 5
phases:
1. Decision Making – selecting method, equipment and final point locations.
2. Fieldwork & Data Collection – making measurements and recording data in the
field.
3. Computing & Data Processing – preparing calculations based upon the recorded
data to determine locations in a useable form.
4. Mapping or Data Representation – plotting data to produce a map, plat, or chart
in the proper form.
5. Stakeout – locating and establishing monuments or stakes in the proper locations
in the field.
9. Stages of surveying :
(i) Taking a general view. This part of the definition is
important as it indicates the need to obtain an overall
picture of what is required before any type of survey
work is undertaken. In land surveying, this is achieved
during the reconnaissance study.
(ii) Observation and Measurement. This part of the
definition denotes the next stage of any survey, which
in land surveying constitutes the measurement to
determine the relative position and sizes of natural
and artificial features on the land.
10. (iii) Presentation of Data:
The data collected in any survey must be presented in a form which allows the
information to be clearly interpreted and understood by others. This presentation
may take the form of written report, bills of quantities, datasheets, drawings and in
land surveying maps and plan showing the features on the land.
11. 2 Categories of Surveying:
1. Plane Surveying – surveying with the reference base for fieldwork and
computations are assumed to be a flat horizontal surface.
Generally within a 12 mile radius the pull of gravity is very nearly parallel to that at any
other point within the radius and thus horizontal lines can be considered straight. Up to
100 sq km area ca be easily mapped with plane surveying.
13. In plane surveying relatively small areas are involved and the area under
consideration is taken to be a horizontal plane. It is divided into three branches.
- Cadastral surveying
- Topographical surveying
- Engineering surveying
14. Cadastral surveying
These are surveys undertaken to define and record the boundary of properties,
legislative area and even countries.
It may be almost entirely topographical where features define boundaries with
the topographical details appearing on ordinance survey maps.
In the other hand, accurately surveyed beacons or markers define boundaries,
corner or line points and little account may be taken of the topographical
features
15.
16. Topographical Survey
These are surveys where the physical features
on the earth are measured and maps/plans
prepared to show their relative positions both
horizontally and vertically.
The relative positions and shape of natural and man –made features over an area
are established usually for the purpose of producing a map of the area of for
establishing geographical information system.
17. Engineering Survey
These are surveys undertaken to provide special information for construction of
Civil Engineering and building projects.
The survey supply details for a particular engineering schemes and could include
setting out of the work on the ground and dimensional control on such schemes.
18. Geodetic Survey
Takes into account the true size, shape, and gravity fields of the Earth
The geoid is the equipotential surface of the Earth’s gravity
field which best fits global mean sea level
Geodetic Surveying – surveying technique to determine
relative positions of widely spaced points, lengths, and
directions which require the consideration of the size and
shape of the earth. (Takes the earth’s curvature into account.)
• Provides significant precision
• Establishes highly accurate
control networks
Images courtesy NOAA
http://celebrating200years.noaa.gov/foundations/gravity_surveys/
19. In geodetic survey, large areas of the earth
surface are involved usually on national basis
where survey stations are precisely located large
distances apart.
Account is taken of the curvature of the earth,
hence it involves advanced mathematical theory
and precise measurements are required to be
made.
Geodetic survey stations can be used to map out
entire continent, measure the size and shape of
the earth or in carrying out scientific studies such
20. Geodetic vs. Plane Survey
Horizontal Plane
PlumbLine
Rod
Geodetic Survey
Line of equal elevation
Plane Survey
Line of equal elevation
Geoid or other Datum
Earth’s surface
Rod
21. CLASSIFICATION OF SURVEYORS
Surveying is made up of various specializations known as sectors or classes as shown below:
1. General Practice Surveyors: • Surveyors under this class are mostly concerned with valuation
and investment.
Valuation surveyors deal with property markets, land and property values, valuation procedures
and property law.
Investment surveyors help investors to get the best possible return form property.
They handle a selection of properties for purchase or sale by pension funds, insurance
companies, charities and other major investors.
They also specialize in housing policy advice, housing development and management.
22. 2. Planning and Development Surveyors
They are concerned with preparing planning applications and negotiating with
local authorities planners to obtain planning permission.
3. Building Surveyors
Their work involves advising on the construction, maintenance, repair and
refurbishment of all types of residential and commercial property.
The analysis of building defects is an important part of a building surveyors
discipline.
23. 4. The Quantity Surveyors
They evaluate project cost and advice on alternative proposals.
They also ensure that each element of a project agrees with the cost plan
allowance and that the overall project remains within budget.
5. Rural Practice Surveyors:
Surveyors in rural practice advice land owners, farmers and others with interests in
the country side.
They are responsible for the management of country estates and farms, the
planning and execution of development schemes for agriculture, forestation,
recreation, sales of properties and live stock.
24. 6. Mineral Surveyors
They plan the development and future of mineral workings.
They work with local authorities and the land owners on planning applications and
appeals, mining laws and working rights, mining subsidence and damage, the
environmental effects of land and rehabilitation of derelict land and deep
underground mines.
25. 7. Land surveyors:
They measure land and its physical features accurately and record them in the
form of a map or plan for the purpose of planning new building and by local
authorities in managing roads, housing estates, and other facilities.
They also undertake the positioning and monitoring for construction works.
This branch of survey is more concerned with Geography and Geomatics. Besides
Civil Engineers are also more concerned with this type of surveys.
26. 7 Types of Surveys:
1. Photogrammetry – mapping utilizing data obtained by camera or other sensors
carried in airplanes or satellites.
2. Boundary Surveying – establishing property corners, boundaries, and areas of land
parcels.
3. Control Surveying – establish a network of horizontal and vertical monuments that
serve as a reference framework for other survey projects.
4. Engineering Surveying – providing points and elevations for the building Civil
Engineering projects.
27. 7 Types of Surveys:
5. Topographic Surveying – collecting data and preparing maps showing the
locations of natural man-made features and elevations of points o the ground for
multiple uses.
6. Route Surveys – topographic and other surveys for long – narrow projects
associated with Civil Engineering projects.
Highways, railroads, pipelines, and transmission lines.
7. Hydrographic Surveying – mapping of shorelines and the bottom of bodies of
water.
Also known as bathymetric surveying.
28. Brief History of Surveying:
1. Surveying had it’s beginning in Egypt about 1400 BC
Land along the Nile River was divided for taxation. Divisions were washed away by
annual floods.
“ROPE-STRETCHERS” Egyptian surveyors were created to relocate the land divisions
(measurements were made with ropes having knots at unit distances).
Extensive use of surveying in building of Egyptian monuments
2. Greeks: expanded Egyptian work and developed Geometry.
Developed one of the earliest surveying instruments – Diopter (a form of level).
29. Brief History of Surveying:
3. Romans: developed surveying into a science to create the Roman roads,
aqueducts, and land division systems.
Surveyors held great power, had schools and a professional organization
Developed several instruments:
• Groma – cross instrument used to determine lines and right angles
• Libella – “A” frame with a plumb bob used for leveling
• Chorobates – 20’ straight edge with oil in notch for leveling
4. Middle Ages: land division of Romans continued in Europe.
Quadrans – square brass frame capable of turning angles up to 90° and has a graduated
scale developed by an Italian named Von Piso.
30. Brief History of Surveying:
5. 18th & 19th Century in the New World: the need for mapping and marking land
claims caused extensive surveying, especially by the English.
1785: United Stated began extensive surveys of public lands into one mile square
sections
30 states surveyed under the U.S. Public Land System (also called the Rectangular
System)
1807: United States Geological Survey founded to establish an accurate control network
and mapping
Famous American Surveyors: George Washington, Thomas Jefferson, George Rogers
Clark, Abe Lincoln and many more.
31. 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).
32. Types of Surveys
Control Survey
Topographic Survey
Property Survey
Site Survey
Construction Survey
33. Control Survey
Establish precise horizontal
and vertical positions of
points that serve as a
reference for other surveys
Courtesy Department of Public Works, Seminole County, FL
Photos Courtesy NOAA
34. Topographic Survey
Gathers data on the location of natural and man-made features, contours,
and ground elevation to create a topographic map
Courtesy USGS
36. Site Survey
(Plot Survey or Lot Survey)
Combination of a property survey and topographic survey
May be required to receive a construction permit
37. Construction Survey
Locates points and elevations that can be used to establish correct locations
and elevations for engineering and architectural projects
Courtesy Isle of Palms, SC Recreation Department
38. National Spatial Reference System (NSRS)
Common set of reference points for all surveys
Horizontal Datum = Collection of
points of known latitude and longitude
Vertical Datum = Collection of points
of known elevation
Benchmark (BM) = Permanent mark
that establishes a point of known
elevation
Wikimedia.org
Courtesy NOAA
http://oceanservice.noaa.gov/education/kits/geod
esy/geo05_horizdatum.html
Editor's Notes
A geodetic survey is based on the true shape of the Earth. The true shape of the Earth is not a sphere but an irregular ellipsoid shape. Many models of the true shape of the Earth exist. One model, the geoid, is a model of the assumed mean sea level which is dependent on the gravitational forces around the world.
The western hemisphere geoid is shown in the computer-generated model on the left. The yellow and orange areas are further from the center of the Earth than the blue areas.
Geodetic surveys use the geoid or another similarly shaped model as a basis. These surveys are performed with great precision and are used to establish highly accurate control networks that provide points of known position throughout the US and the world.
In a geodetic survey, the geoid is taken as the datum. Lines that indicate level surfaces undulate with the strength of the gravitational field. In a plane survey, the curvature the Earth is considered flat, and lines of equal elevation are assumed to be horizontal planes.
In this class, we will perform plane surveys.
Control surveys are used to establish the latitude, longitude, and/or elevation of reference points that can be used for other types of surveys. The image here is published in the Seminole County Geodetic Control Points document (2006), which provides a description of the location of each control point in addition to the latitude, longitude, and/or elevation. These control points can then be used as a basis for topographic, construction, or other surveys.
The photos show survey crew members setting survey marks during control surveys in Alaska. The black and white image was taken near White Pass, Alaska in 1936. The color photo is a more recent shot of a crew member mixing cement to set a mark in a rock in Southeast Alaska.
This is an example of a topographic map for the area surrounding Stowe, Vermont. The contour lines indicate lines of constant elevation.
This is an example of a recorded plat created from a property survey near Mount Pleasant, SC. The property lines are located using a length and a bearing angle.
This site plan shows both property lines and contours from a topographic survey.
Examples of construction surveys include staking a line and grade for a foundation, a fence, or a road.
In the picture, the string lines were laid out based on a construction survey. Notice the surveying equipment to the right in the picture used to ensure that the foundations are poured to the correct elevation.
The top photograph is an example of a horizontal datum marker. The bottom photo shows a benchmark.