What is Surveying? Surveying is the technique of determining the relative position of different features on, above or beneath the surface of the earth by means of direct or indirect measurements and finally representing them on a sheet of paper known as plan or map. Surveying is the means of determining the relative position of points and the relative distances. It is very important in the field of Civil Engineering. We can find uses of surveying in all civil engineering projects. The objectives of surveying may very depending on the type of project. A surveyor must be clear about the objects of surveying. The main objectives of surveying are discussed below. Objectives of Surveying • To determine the relative position of any objects or points of the earth. • To determine the distance and angle between different objects. • To prepare a map or plan to represent an area on a horizontal plan. • To develop methods through the knowledge of modern science and the technology and use them in the field. • To solve measurement problems in an optimal way.
Importance of Surveying • The first necessity in surveying is to prepare a plan and a section of an area to be covered by the project. From these prepared maps and sections the best possible alignment, amount of earthwork and other necessary details depending upon the nature of the project can be calculated. • The planning and design of all Civil Engineering projects such as railways, highways, tunneling, irrigation, dams, reservoirs, waterworks, sewerage works, airfields, ports, massive buildings, etc. are based upon surveying measurements. • During execution of the project of any magnitude is constructed along the lines and points established by surveying. • The measurement of land and the fixation of its boundaries cannot be done without surveying. • The economic feasibility of the engineering feasibility of a project cannot be properly ascertained without undertaking a survey work. • The execution of hydrographic and oceanographic charting and mapping requires. • Surveying is used to prepare a topographic map of a land surface of the earth.
Surveying is the process of finding the relative position of various points on the surface of the earth by measuring distance among them and setting up a map to any reasonable scale. Various methods of surveying are established on very simple fundamental principles. The surveying basic principles can be stated under two aspects. Principles of Surveying 1. To locate the position of a point by measurement from two reference points 2. To work from whole to part 3. Uses of Surveying 4. Some of the numerous functions of surveying are given below. 5. Topographical maps showing hills, rivers, towns, villages, forests etc. are prepared by surveying. 6. For planning and estimating new engineering projects like water supply and irrigation schemes, mines, railroads, bridges, transmission lines, buildings etc. surveying is required. 7. Cadastral Map showing the boundaries a field houses and other properties are prepared by surveying. 8. Engineering map showing the position of engineering works like roads, railways, buildings, dams, canals etc. are prepared through surveying.
9. To set out a work and transfer details from map to ground knowledge of surveying is used. 10. For planning navigation routes and harbors, marine and hydro-graphic surveying are used. 11. To help military strategic planning, military maps are prepared by surveying. 12. For exploring mineral wealth, mine survey is necessary 13. To determining different strata in the earth crust, geological surveys are required 14. Archaeological surveys are used to unearth relics of antiquity. 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