Some vital definitions in surveying

Surveying is the art to create horizontal measurements for finding out the relative position of several objects on the surface of the earth.

Objective of surveying - To work from the whole to the part, To determine the new station by minimum two methods

Categorization of surveying:

1. Geodetic surveying: It is also known as trigonometrically surveying. In this type of surveying, the curvature of the earth is taken into consideration. It handles long distance and large area. The joining line in earth is curved and develops arc of a two point great circle.

2. Plane surveying: Plane surveying handles small area and short distances. The curvature is the earth and it is not taken into consideration. The line that is attached in two points in earth surface is considered as a straight line. Geodetic surveying is more accurate with regard to plane surveying.

Classification of surveying on the basis of instruments applied:

a. Chain survey
b. Compass survey
c. Theodolite survey
d. Plane table survey
e. Tachometric survey
f. Photographic survey
g. Aerial survey

Categorization of scales:

a. Plain scales
b. Diagonal scale
c. Comparative scale
d. Vernier scale

Well conditioned triangle: It is described as there is no include angle is under 30 and more than 120. Equilateral triangle is the superior conditioned triangle.

Jargon in chain surveying:

a. Survey station
b. Base line
c. Chain line
d. Tie line
e. Offsets

Categories of chains applied in surveying:

a. Metric chain
b. Non metric chain
c. Gunter’s chain
d. Engineers chain
e. Revenue chain

To get more details, go through the following link www.learntocivilfield.com



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Published By
Rajib Dey
www.constructioncost.co
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Types of Engineering Surveying

Surveying is primarily categorized as below :

1. Plane surveying

2. Geodetic Surveying

Plane surveying refers to the survey in which the earth surface is considered as plane and the curvature of the earth is not taken into consideration. The plane surveys encompass only over lesser areas and the lines linking any two points on the surface of the earth are defined as straight lines and the angles among such lines are assumed as plane angles. To start with plane surveys, understanding of plane geometry and trigonometry is essential. In plane surveys, the covered are must be up to 260 km. In this regard, please remember that the variance in length among the arc and the subtended chord on the earth surface toward a distance of 18.2 km is only 0.1 m.

Geodetic Surveying refers to the particular type of surveying in which the shape of the earth should be considered primarily. All lines assigned in the surface are arc or curved lines and the angles belong to spherical angles. So, it contains spherical trigonometry. These measurements are applied for modifying curvature on maps and plans. Geodetic surveys also offer a wide array of control points over the Earth's surface which produce perfect plane surveys. All Geodetic surveys comprise work of larger magnitude and superior degree of accuracy. The motive of geodetic survey is to obtain the exact position on the surface of the earth. Geodetic surveys are initiated with extreme degree of precision to arrange broadly spaced control points on the earth surface for successive plane surveys.

Categorization of surveying

Surveys are also secondarily categorized with no. of headings which describe the applications or objectiveØÇ of resulting maps.

Categorization is done on the basis of type of field and there are three types of surveying :

1. Land Surveying: It is further divided as i) Topographical survey ii) Cadastrial Survey and iii) City Survey. It usually handles natural or artificial features on land like rivers, streams, lakes, wood, hills, roads, railways, canals, towns, water supply systems, buildings & properties etc.

2. Marine Surveying: Marine or hydrographic survey handles bodies of water for navigation, water supply, harbour works or for assessing mean sea level. The work comprises measurement of discharge of streams, arranging topographic survey of shores and banks, consiering and discovering soundings to ascertain the depth of water as well as observing the variations of the ocean tide.

3. Astronomical Surveying: The astronomical survey provides the surveyor means of ascertaining the absolute location of any point or the absolute location of and direction of any line on the surface of the earth. ‪

There are four types of surveying which are given below:

1. Geological Surveying

2. Mine Surveying

3. Archaeological surveying

4. Military surveying

Categorization on the basis of types of instruments applied: 

1. Chain surveying

2. Compass surveying

3. Plane table surveying

4. Theodolite surveying

5. Tacheometric surveying

6. Photographic surveying

Categorization on the basis of techniques used:

1. Triangulation surveying

2. Traverse surveying

Ref.: www.civileblog.com

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Published By

Rajib Dey

www.constructioncost.co

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