Surveying

 

Surveying: Studying is the craft of deciding the overall places of various articles on the outer layer of the earth by estimating the level distances among them, and by setting up a guide to any appropriate scale. Along these lines, in discipline, the estimations are taken uniquely in the level plane.

Surveying is primarily classified as under: 

1. Plane surveying 

2. Geodetic Surveying 

Plane Surveying is that kind of looking over in which the mean surface of the earth is considered as a plane and the spheroidal shape is dismissed. All triangles shaped by study lines are viewed as plane triangles. The level line is viewed as straight and all plumb lines are viewed as equal. In regular daily existence were are worried about little piece of earth's surface and the above presumptions is by all accounts sensible considering the way that the length of a circular segment 12 kilometers extended lying in the world's surface is just 1cm more noteworthy than the subtended harmony and further that the contrast between the amount of the points in a plane triangle and the amount of those in a round triangle is just one second for a triangle at the world's surface having an area of 195 sq. km. Geodetic Surveying is that kind of looking over in which the state of the earth is considered. All lines lying in the surface are bended lines and the triangles are round triangles. It in this way, includes circular geometry. All Geodetic overviews incorporate work of bigger greatness and serious level of accuracy. The object of geodetic overview is to decide the exact situation on the outer layer of the earth, of an arrangement of generally far off directs which structure control stations toward which studies of less accuracy might be alluded. Order of reviewing Surveys might be optionally grouped under no. of headings which characterize the utilizations or motivation behind coming about maps.

 Classification based upon nature of field: 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. 

1. 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. 

2. Astronomical Surveying: The astronomical survey 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 Triangulation is a method of surveying that measures the angles in a triangle formed by three survey control points. Using trigonometry formula and the measured one side’s length, the other distances in the triangle are calculated respectively. 

2. Traverse surveying It is also a well-known method of surveying. A traverse is a series of connected lines whose lengths and direction are measuring instrument and tape or chain respectively