Test: Traverse Surveying - Civil Engineering (CE) MCQ

The double meridian distance of a line is equal to the sum of the meridian distances of the two extremities, which is useful for the determination of the required area of the plot.

• The sum of the meridian distances of the ends of a survey line.
• In practice, assuming a closed traverse with the meridian of reference passing through the initial station, the double meridian distance (DMD) of the first course (line) is equal to the departure of that course; the double meridian distance of each succeeding course (line) is equal to the double meridian distance of the preceding course, plus the departure of the preceding course, plus the departure of the course itself.
• If the DMD of each course is multiplied by the latitude of the corresponding course, double areas are obtained, from which the area of the tract can be obtained.
• By a strictly analogous procedure, double parallel distances (DPD) can be computed, using the latitudes of the successive courses instead of departures, and using an east-west line as the reference parallel.

Answer: a
Explanation: The latitude of the survey line may be defined as its coordinate length measured parallel to an assumed meridian direction. True north or magnetic north or any other reference direction.

Traverse is a method in the field of surveying to establish control networks.

Traverse surveying: 

• A traverse is a series of connected lines whose lengths and directions are to be measured and the process of surveying to find such measurements is known as traversing.
• In Traverse, surveying measurements are carried out in a long series of interconnected survey lines, either from a closed or an open traverse.
• In general, chains are used to measure the length and a compass or theodolite is used to measure the direction of traverse lines.
• Methods of traversing: 1. Chain traversing 2. Compass traversing 3. Theodolite traversing  4. Plane table Traversing.

​Cadastral surveying: 

• These involve determination and plotting boundary locations of individual land holding and/or laying out new property boundaries.

Topographic surveying: 

• For the preparation of plans and maps delineating natural and man-made surface features and ground undulations.  

Hydrographic surveying: 

• To obtain information and data about underwater features of the ground, e.g. showing shorelines, water depths, the shape of the river bed, and other marine features.

The latitude of the line is positive when measured northward. It is termed as northing.

All of the above are Advantages of Traverse networks.

Principle of Compass Surveying :

• In compass traversing the directions of survey lines are fixed by angular measurements and not by forming a network of triangles.
• A compass survey is one in which the traverse work consists of a series of lines the lengths and directions of which are measured with a chain or a tape, and with an angular instrument respectively.

A traverse may be classified as:
Closed traverse (link traverse):

• A closed traverse is a traverse in which the sides of a traverse form a closed polygon.

Open traverse (loop traverse):

• An open traverse is a traverse in which the sides of the traverse do not form a closed polygon.

The latitude of the line is negative when measured southward. It is termed as southing.

There are mainly two types of traverse: closed and open.

Magnetic declination: At any place horizontal angle between true meridian and magnetic meridian is called magnetic declination.
For Eastern Declination:
α = β + θ_e or T.B = M.B + θ_e
Here, α = True bearing (T.B)
β = Magnetic bearing (M.B), and
θ_E = Eastern declination
For Western Declination:
α = β – θ_w or T.B = M.B – θ_w
Here, θ_w = western declination.
Calculation:
Magnetic bearing of a line AB = 132°45’
Declination = 10°20’ West
∴ True bearing = 132°45’ - 10°20’ = 122°25' = S57°35’E