To Carry Out the Surveying to Find Out the Contour Map of Given Site (smit Compound) & Do Profile Levelling

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Because more commercial and industrial construction jobs have become centered on Building Information Model (BIM) the coordinates for virtually every pipe, conduit, duct and hanger support are available with digital precision. The application of communicating a virtual model to a tangible construction potentially eliminates labor cost related to moving poorly measured systems, as well as time spent laying out these systems in the midst of a full blown construction job in progress.

PROCEDURE

Creating Contour Map

- Initially the first station point is selected and instrument is set up with proper levelling and centering.

- Now once the adjustment of the instrument is completed, with some appropriate value of benchmark or known value benchmark is set in the instrument.

- Now the various readings, i.e. the reduced level of various points called foresight reading of the farthest visible point is measured or taken and the last visible point is marked which is the change point and second station point.

- Now the instrument is shifted to the second point and the staff, i.e. the prism is kept at first station point and the back sight reading is taken.

- Now again from so set up second station point again foresight readings up the last visible point is taken and again the last point is marked to change the station.

- In this way, the process is continued till the whole target area is surveyed.

- When the surveying of the target area is completed, the data record in the total station is transferred to the computer and is executed and the surface and contour map of the area is finally obtained.

- Finally so obtained contour map of required area from the surface is converted into an AutoCAD drawing.

Profile Levelling

- To carry out profile levelling, a level is placed at a convenient location (say L1) not necessarily around the line of observation.

- The instrument is positioned in such a way that first back sight can be taken clearly on a benchmark.

- Then observations are taken at regular intervals (say at 1, 2, 3, and 4) along the central line and foresight at a properly selected turning point (say TP1).

- The instrument is then re-positioned to some other convenient location (say L2).

- After proper adjustment of the instrument, observations are started from TP1 and then at regular intervals (say at 5, 6 etc.) terminating at another turning point, say TP2 .

- Staff readings are also taken at salient points where marked changes in slope occur.

- The distances as well as direction of lines are also measured.

- Profile levelling is carried out in both transverse as well as longitudinal direction.

Prism

The prism shown below is another tool of total station that reflects back the ray of light transmitted by the total station back to it and assists to provide the reduced level of the point at which the prism is placed.

[pic 2]

Tripod Stand

It is the three legged stand that is used to hold a total station in position.

[pic 3]