The art of measuring the distances and angles on ground in such a way that it becomes reproducible on a map which is drawn to scale later on, is called surveying.Surveying is a science as well as an art, by which studies are made of the objects present on the ground and below the ground at different points. Knowing about the relative position of various objects, determination of distances between them, measurement of angles, measurement of height,determination of boundaries and relative heights of various points come under the purview of surveying.It is very essential to mark the various points on the land, boundary lines of the proposed construction sites and levels (heights) of the various locations before starting the construction of building, bridge, embankment, railway line etc.After performing the measurements of the shape, size and location of objects on ground, the details are plotted on paper (drawing sheet). After the completion of drawing which may be one or more than one, describing the details, the construction process is started. After determining the details of the soil strata below ground and bearing capacity of soil which is called Geo technical survey, the depth of earth work is decided by the engineer. All these things are interrelated and forms the part of the total survey work.