Surveying♣It is the art of determination of horizontal distances,differences in elevation, directions, angles, locations, areas andvolumes on or near the surface of the earth.♣ It involves the measurement and recording of the size andshape (including the vertical shape) of an area on the earthssurface.
The process of survey divided into two parts: (a) Field work- taking measurements (b)Office work- computing and drawing
Object of survey♣The primary object of survey is the preparation of plan ormap.♣The results of surveys when plotted and drawn on paperconstitute a plan.♣The representation is called a map, if the scale is small. Ifthe scale is large, it is called a plan.
Primary division of surveying Surveying may be divided into two general classes: (a) Geodetic surveying (b)Plane surveyingGeodetic surveying is also called trigonometrical surveying . In this survey, thecurvature of the earth is taken into account, since large distances and areas arecovered.In plane survey, the earths surface is considered as a plane. The curvature ofthe earth is not taken into account, as the surveys extend only to smallareas.
I. Classification based upon the nature of the field of survey: (a) Land Surveys. (b) Marine or Navigation Surveys. (c) Astronomical Surveys.
II. Classification upon the object of survey:(i) Archaeological surveys.(ii) Geological Surveys -for determining different strata in theearths crust.(iii) Mine Surveys- for exploring mineral wealth such as gold,coal, etc.(iv) Military Surveys- for determining points of strategicimportance both offensive and defensive.
III. Classification based upon the methods employedin survey:(a) Triangulation Surveys. (b) Traverse Surveys
IV. Classification based upon the instrumentemployed: (i) Chain Surveys. (ii) Theodolite Surveys. (iii) Tacheometric Surveys. (iv) Compass Surveys. (v) Plane Table Surveys. (vi) Photographic and Aerial Surveys.
Uses of survey:The planning of all engineering and construction projectsextending over large areas, such as highways, railways,irrigation, water supply etc., are based upon elaborate andcomplete surveys.