Surveying-levelling
July 31, 2020
What is surveying and classification of surveying and its classification
What is surveying?
Surveying is the important topics in civil engineering. In this we have to determine the relative positions between the objects which is on, above or beneath the earth surface. It is done by means of direct or indirect measurement and surveying meaning finally representing them on the sheet of paper with suitable scale which is known as a plan or map. It is done by various equipments like chain, tape, compass, theodolite, tacheometer etc
Object of surveying
The purpose or aim of surveying is to be prepared a map to point out the relative positions of the item on the surface of earth. Types of surveying The map is drawn with the assistance of an appropriate scale. The surveying shows the natural features of a rustic like rivers, forest, hills, valley ,etc and artificial features like dam, reservoirs, roads, railway ,etc.
Uses of surveying :-
Surveying may be used for the following various application are as follows -
- To prepare an engineering map while shows the details of engineering Works such as roads, railway, canals, bridges, etc.
- Prepare a codastral map showing the boundaries of a field, house, and other properties
- To prepare a geological map showing area including the underground resources or different strata in the earth crust.
- To prepare an archaeological map including the un-eathening relics of antiquity.
- To prepare topographical map which showing rivers, forests, etc.
Classification of surveying
A) Primary surveying
B) Secondary surveying
A) Primary surveying
There are two types of primary surveying :-
1) Plane surveying
The surveying in which the curvature of earth is not taken into consideration is known as plane surveying.
It is carried out over a small area. So the surface of earth is considered plane. The level line is considered as straight and plump bob line is considered as parallel.
All triangles formed by survey line is considered as plane trianges. Generally, area less than 250 kilometre square are treated as a plan.
2) Geodetic surveying
The surveying in which the curvature of earth is taken into surveying mcq question consideration is known as geodetic surveying. It is also known as trigonometry surveying.
All lines lying in the surface are curved and plump bob line intesect each other and the triangles are spherical triangles. This survey extended over a large area (more than 250 kilometre square) I and where degree of accuracy required high.
B) Secondary surveying
According to base on instrument
- Chain surveying
- Compass surveying
- Theodolite surveying
- Tacheometric surveying
- Plane table surveying
- Photographical or aerial surveying
1) Chain surveying
It is type of surveying in which only linear measurements are made in the field. The principal of chain surveying is triangulation.
2) Compass surveying
It is type of surveying in which the length of survey line is measured by chain or tape and the direction of survey line is measured by compass is known as compass surveying.
3) Theodolite surveying
The theodolite is an accurate instrument which is used for the measurement of vertical angle and horizontal angle.
4) Tacheometric surveying
A branch of surveying in which horizontal and vertical distance of a point are obtained by angular observations with a tacheometer is known as tacheometric surveying.
5) Plane table surveying
Plane table may be a graphical method of surveying within which the sector observations and plotting proceed simultaneously.
6) Photographic or aerial surveying
It is type of surveying in which camera is used from the helicopter or ground surface is known as aerial surveying.
According to based on method
- Triangulation surveying
- Traverse surveying
1) Triangulation surveying
It is type of Surveying in which large area is divided into the number of small wells triangles and find out about it is known as a triangulation surveying.
These methods are generally occurs in chain surveying.
2) Traverse surveying
A traverse surveying consists of a series of connected lines with the help of chain or tape and direction are determined by compass or theodolite.
There are two types of traverse surveying
- Open traverse surveying
- Close traverse surveying
According to based on objects
- Geological surveying
- Archeological surveying
- Military surveying
- Mine surveying
1) Geological surveying
It is type of surveying which is related to different strata in the earth crust.
2) Archaeological surveying
It is type of surveying which is used to collect the data related to the relics of antiquity.
3) Military surveying
It is type of surveying which is done for the strategic importance of defense is known as military surveying.
4) Mine surveying
It is type of surveying which is used for the mineral wealth or collecting the information related to mine is called mine surveying.
According to based on the nature of field
- Land surveying
- Marine surveying
- Astronomical surveying
1) Land surveying
It is type of surveying which is done to find out relative positions of any point on the ground.
There are following types of land surveying
- City surveying
- Codastral surveying
- Engineering surveying
- Topographical surveying
City surveying
It is type of land surveying which
is done for the construction of street, water supply, sanitary, etc.
Codastral surveying
It is type of land surveying which is done for fixing the property line such as boundaries of a field is called codastral surveying.
Engineering surveying
It is type of land surveying which is done for the construction of engineering works surveying diploma such as roads, railway, reservoirs, irrigation canals, etc is called engineering surveying.
Topographical surveying
It is type of land surveying surveying and levelling by nn basak which located the relative positions of natural features such as rivers, hills etc and artificial features such as dam, roads, railway, etc is called topographical surveying.
2) Marine or hydrographical surveying
It is type of surveying which is related to water bodies for the purpose of navigation & harbor is known as marine surveying.
3) Astronomical surveying
It is type of surveying which is done for the determination of relative positions of heavenly bodies such as sun, stars, moon, etc is known as astronomical surveying.
