1. TYPES OF SURVEYING
December 24, 2016 shanmukha 10 Comments
Surveying is primarily classified as under:
1. Plane surveying
2. Geodetic Surveying
Plane Surveying is that type of surveying in which the mean surface of the earth is considered as a plane
and the spheroidal shape is neglected. All triangles formed by survey lines are considered plane triangles.
The level line is considered straight and all plumb lines are considered parallel. In everyday life were are
concerned with small portion of earth’s surface and the above assumptions seems to be reasonable in light
of the fact that the length of an arc 12 kilometers long lying in the earth’s surface is only 1cm greater than
the subtended chord and further that the difference between the sum of the angles in a plane triangle and
the sum of those in a spherical triangle is only one second for a triangle at the earth’s surface having an
area of 195 sq. km.
Geodetic Surveying is that type of surveying in which the shape of the earth is taken into account. All
lines lying in the surface are curved lines and the triangles are spherical triangles. It therefore, involves
spherical trigonometry. All Geodetic surveys include work of larger magnitude and high degree of
precision. The object of geodetic survey is to determine the precise position on the surface of the earth, of a
system of widely distant points which form controlstations to which surveys of less precision may be
referred.
Classification of surveying
Surveys may be secondarily classified under no. of headings which define the uses or purpose of resulting
maps.
Classification based upon nature of field:
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2. There are three types of surveying based upon the nature of field which are as follows:
1. Land Surveying: It can be further classified as i) Topographical survey ii) Cadastrial Survey and
iii) City Survey. It generally deals with natural or artificial features on land such as rivers, streams,
lakes, wood, hills, roads, railways, canals, towns, water supply systems, buildings & properties
etc.
2. Marine Surveying: Marine or hydrographic survey deals with bodies of water for purpose of
navigation, water supply, harbour works or for determination of mean sea level. The work consists
in measurement of discharge of streams, making topographic survey of shores and banks, taking
and locating soundings to determine the depth of water and observing the fluctutations of the
ocean tide.
3. Astronomical Surveying: The astronomicalsurvey offers the surveyor means of determining the
absolute location of any point or the absolute location of and direction of any line on the surface of
the earth. This consists in observations to the heavenly bodies such as the sun or any fixed star.
Classification based on object:
Based on object, there are four types of surveying which are as follows:
1. Geological Surveying
2. Mine Surveying
3. Archaeological surveying
4. Military surveying
Classification based on instruments used:
Based on various types of instruments used, surveying can be classified into six types.
1. Chain surveying
2. Compass surveying
3. Plane table surveying
4. Theodolite surveying
5. Tacheometric surveying
6. Photographic surveying
Classification based on methods used:
Based on methods adopted, surveying can be categorized into:
1. Triangulation surveying
2. Traverse surveying
Surveying is 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 details.
Types of Surveying
Surveying can mainly be classified into 2 groups-
Plane Surveying
Geodetic or Trigonometrical Surveying
3. Plane Surveying
Plane surveying deals with small areas on the surface of the earth assuming the surface of the
land to be plane. So curvature of the earth is neglected. Plane surveying can further be
subdivided in the following ways:
Chain Surveying
Area to be surveyed is divided into a number of triangles
The length of the sides are measured and the interior details recorded
Whole are then plotted on a drawing sheet to a suitable scale to produce the map
Traverse Surveying
The plot of the plan is enclosed by a series of straight lines making angles with each
other.
The length of the lines and angles are measured and plotted with details on a drawing
paper to a suitable scale to produce the map
Plane Table Surveying
The observations and plotting are done simultaneously
An art paper or sheet is fixed on a calibrated plane table
The field observations are taken and recorded side by side on the paper and eventually
the map is prepared.
Ordinary Leveling
The elevations of different points on the earth surface are determined.
Provides all the elevation data needed for construction activities
Geodetic Surveying
Geodetic surveying deals with vast areas, so curvature has to be considered. Geodetic
surveying can be subdivided in the following ways:
Triangulation
A network of well-defined triangles is formed on the plot of land to be surveyed.
One of the lines is considered as the baseline, all other lines and angles are then
measured accordingly.
Reciprocal Leveling
Used in leveling across streams, gullies, and other obstructions to eliminate
instrumental errors
Level readings are taken from two setups at two different points
The difference in levels between two sites with obstructions is determined through
this survey
4. Tacheometry or Stadia Surveying
A telescopic sight instrument is used to measure distances
It incorporates a theodolite controlled by an operator and a level staff held by another
surveyor at a distance.
Both vertical and horizontal distances are computed through stadia (the two horizontal
markings on a theodolite) readings
Astronomical Surveying
The meridian, azimuth, latitude, longitude, etc. of the plot to be surveyed is
determined with the help of celestial bodies.
Photographic surveying
Maps are prepared from photographs taken from suitable camera stations; the stations
can be even airplanes.
The output is a map, a drawing or a 3D model of some real-world scene or object.
