JNTU B.Tech II SURVEYING AND GEOMATICS Previous Question Paper (March - 2022 - R18)

The differences between a Prismatic compass and a Surveyor’s compass regarding reading and tripod usage are as follows:

A closing error occurs in a closed traverse when the final position of the last station, as plotted from the survey measurements, does not coincide with the starting station. It represents the resultant displacement between the calculated end point and the actual starting point.

The graphical method (also known as Bowditch's graphical method) for adjustment is performed as follows:

1. Plot the traverse to a suitable scale on a drawing sheet. Let the closing error be represented by the vector e, which is the distance between the starting point A and the final point A'.
2. Draw a straight line representing the total perimeter of the traverse to a convenient scale.
3. Mark the lengths of individual traverse lines sequentially along this line.
4. At the end of the total length, erect a perpendicular equal to the magnitude of the closing error e.
5. Connect the end of this perpendicular to the start of the line.
6. For each station, draw a perpendicular from the point representing its cumulative distance on the base line to the hypotenuse. These perpendicular segments represent the correction to be applied to the corresponding station point in the plotted traverse.