Q1: What is the principle of chain surveying?
Ans:The principle of chain surveying is triangulation. This means that the area to be surveyed is divided into a number of small triangles which should be well-conditioned. In chain surveying, the sides of the triangles are measured directly in the field using a chain or tape, and no angular measurements are taken.
Q2: What do you mean by triangulation?
Ans:Triangulation is a surveying method in which an area is divided into a series of triangles, and the distances and angles of these triangles are measured to determine the positions of points.
Q3: Why is the triangle preferred to the quadrilateral?
Ans:A triangle is preferred because it is the simplest geometric figure that remains stable and does not deform, whereas a quadrilateral can change shape unless its angles and sides are precisely controlled.
Q4: What is the disadvantage of using ill-conditioned triangles?
Ans:Ill-conditioned triangles have very small or very large angles, making them difficult to measure accurately and leading to significant plotting errors.
Q5: What is reconnaissance survey?
Ans:A reconnaissance survey is a preliminary inspection of the survey area to identify key features and plan the main survey work accordingly.
Q6: What is an index sketch?
Ans:An index sketch is a rough drawing that shows the locations of survey stations and major landmarks, helping in fieldwork planning and referencing.
Q7: What is 'base line of survey'?
Ans:The base line is the most important line of the survey on which the framework of the survey is built. It is usually the longest main survey line and should be measured very accurately.
Q8: How is the north line of the chain survey map fixed?
Ans:The north line of the chain survey map is fixed by taking the magnetic bearings of the base line using a compass.
Q9: What should be the maximum length of offset?
Ans:The maximum length of an offset depends on the precision required, but generally, offsets should be kept short to reduce errors. Perpendicular offsets are preferred for accuracy.
Q10: How is a station marked on the ground?
Ans:A station is marked on the ground using wooden pegs, ranging rods, or nails, depending on the type of survey being conducted.
Q11: What is the need for a reference sketch?
Ans:A reference sketch is needed to ensure that survey stations can be easily located again if required, reducing the chances of errors in future surveys.