What is surveying and it's classification ?

 

Surveying:

Surveying is the art of determining the  relative positions of points on, above or beneath the surface of the earth by means of direct or indirect measurements of distance, direction and elevation. It also includes the art  of establishing points by predetermined angular and linear measurements. The application of surveying required skill as well as the knowledge of mathematics, physics and to some extent astronomy.

Levelling is a branch of surveying the object of which is (i)to find the elevations of points with respect to a given elevation or at different elevations  with respect to a given or assumed datum. The first operation is required to enable the works to be designed while the second operation is required in the setting out of all kinds of engineering works . Levelling deals with measurements in a vertical plane.

 

CLASSICFICATION :

Surveys mau ne classified under headings which define the uses or purpose of the resulting maps:

(A) Classification base upon the nature of the field survey:

             (1) Land Surveying:

                        (i)Topogrphical  survey:This consists of horizontal and vertical location of certain points by linear and angular measurement and is made to determine the natural features of a country such as river,streams,lakes,woods,hills etc.

                       (ii)Cadastral survey: Cadastral survey 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.

                        (iii)City survey: They are made in connection with the construction of streets, water supply, sewers and other works.

            (2) Marine or Hydrographic Survey: Marine or hydrographic survey deals with bodies of water for purpose of navigation, water supply ,harbor works or for the determination of mean sea level.

            (3)Astronomical  survey:The astronomical survey offers the surveyor of determining the absolute location of nay point or the absolute location and direction of nay line on the surface of the earth.

(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) Archeological Survey: This is used for unearthing relics of antiquity.

(C) Classification based on instruments used:

            (1) Chain survey .

           (2) Theodolite survey.

           (3) Travers survey.

           (4) Triangulation Survey

           (5) Tacheometric Survey

           (6) Plane table survey