CLASSIFICATION OF SURVEYING
Surveying may be classified as follows :
(A) CLASSIFICATION BASED UPON THE NATURE OF THE FIELD SURVEY :
(1) Land Surveying :-
(i) Topographical Survey :
This consists of horizontal and vertical location of certain points by linear and angular measurements and is made to determine the natural features of a country such as rivers, streams, lakes, woods, hills, etc., and such anificial features as roads, railways, canals, towns and villages.
(ii) Cadastral Surveys :
Cadastral surveys are made incident to the fixing of property lines, the calculation of land area, or the transfer of land property from one owner to another. They are also made to fix the boundaries of municipalities and of State and Federal jurisdictions.
iii) City Surveying :
They are made in connection with the construction of streets, water supply systems, sewers and other works.
2) Marine or Hydrographic Survey :
Marine or hydrographic survey deals with bodies of water for purpose of navigation, water supply, harbour works or for the 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 fluctuations of the ocean tide.
3) Astronomical Survey :
The astronomical survey offers the surveyor means of determining the absolute location of any point or the absolute location 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.
(B) CLASSIFICATION BASED ON THE OBJECT OF SURVEY :
1) Engineering Survey :
This is undertaken for the determination of quantities or to afford sufficient data for the designing of engineering works such as roads and reservoirs, or those connected with sewage disposal or water supply.
2) Military Survey :
This is used for determining points of strategic importance.
3) Mine Survey :
This is used for the exploring mineral wealth.
4) Geological Survey :
This is used for determining different strata in the earth’s crust.
5) Archacological Survey :
This is used for unearthing relics of antiquity.
(C) CLASSIFICATION BASED ON INSTRUMENTS USED :-
An alternative classification may be based upon the instruments or methods employed, the chief types being :
1) Chain survey :
Chain surveying is that type of surveying in which only linear measurements are made in the field.
This type of surveying is suitable for surveys of small extent on open ground to secure data for exact description of the boundaries of a piece of land or to take simple details.
2) Compass Survey :
Compass surveying is a type of surveying in which the directions of surveying lines are determined with a magnetic compass, and the length of the surveying lines are measured with a tape or chain.
3) Theodolite survey :
In theodolite survey the horizontal angles are measured with theodolite more precisely than compass and linear measurements are made with a chain or a tape.
4) Traverse survey :
Traversing is that type of survey in which a number of connected survey lines form the framework and the directions and lengths of the survey lines are measured with the help of an angle or direction) measuring instrument and a tape (or chain) respectively.
5) Triangulation survey :
Triangulation is a basic method of surveying in which entire area to be surveyed is divided into a network of triangles.
6) Tacheometric survey :
A special type of theodolite known as tacheometer is used to determine horizontal and vertical distance indirectly.
7) Plane table survey :
Plane table surveying is a graphical method in which Field works and plotting both are done simultaneously.
8) Photogrammetric Survey :
Photogram metric surveying or photogrammetry is the science and art of obtaining accurate measurements by use of photographs.
9) Aerial Survey :
Aerial survey is a method of collecting geomatics or other imagery by using airplanes, helicopters or other aerial methods.
10) EDM :
Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves.