Question

Offsets are of two types that are ________ .

• A. Perpendicular and oblique
• B. Straight and oblique
• C. Horizontal and vertical
• D. Horizontal and curved oblique

Answer 1

The correct option is A Perpendicular and oblique

An offset is the lateral distance of an object or ground feature measured from a survey line

There are two types of offsets :

I. Perpendicular offsets

II. Oblique offsets

I. Perpendicular offsets or simply offsets: When the lateral measurements of locating details are at right angles to the chain line, the offsets are called perpendicular offsets.

Simply, when the angle of offset is ${90}^{\circ },$ it is called perpendicular offset.





II. Oblique offsets: When the lateral measurements for fixing details are not at right angles to the chain line, the offsets are called oblique offsets.

Simply, when the angle is other than ${90}^{\circ },$ an offset is called oblique offset.


Uses of offset in horizontal measurement in chain surveying :

(i) Offsets are used to locate details like boundaries, culverts etc measured right or left of chain line.

(ii) Any point or an object at some distance away from chain line can be located by measuring distance and angle from a point on chain line.

(ii) Method of perpendicular offsets involve less measurement on the ground.