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

Chain surveying is the simplest method of surveying where the area is divided into a network of triangles and the sides are measured directly with a chain or tape. The execution involves several systematic operations:

1. Reconnaissance: The surveyor walks over the entire area to understand the topography, identify potential obstacles, and select suitable station points to form well-conditioned triangles.
2. Marking Stations: Once the layout is determined, station points are marked on the ground using ranging rods, wooden pegs, or iron spikes to ensure they remain visible throughout the survey.
3. Reference Sketching: A field book is used to draw a neat sketch of the area, showing the stations, survey lines, and important physical features (buildings, trees, fences) to be located.
4. Running Survey Lines: This involves ranging, where intermediate points are established on a long survey line to ensure it is straight, followed by chaining, where the actual distance is measured using a chain or tape.
5. Taking Offsets: Lateral measurements are taken from the main survey lines to locate the positions of various objects. These can be perpendicular offsets (taken at right angles to the chain line) or oblique offsets (taken when objects are at an angle).
6. Recording in Field Book: All measurements, including chainages and offsets, are meticulously recorded in a field book. The double-line or single-line method is used to represent the survey line, with offsets recorded to the left or right as observed.
7. Plotting: Finally, the data is transferred to a drawing sheet. The framework of triangles is plotted first, followed by the details located via offsets, to produce an accurate map of the surveyed area.