Tacheometric Surveying MCQ Quiz in বাংলা - Objective Question with Answer for Tacheometric Surveying - বিনামূল্যে ডাউনলোড করুন [PDF]

Concept:

Slope, temperature, and tension corrections are required in chain surveying, not in Tacheometric surveying.

In Method of Tacheometry

In this figure, the Line of sight is horizontal and staff is held truly vertical.

Tacheometric distance formula

\(D=\left(\dfrac{f}{i}\right)s + (f+d)\)

D = KS + C

Where,

K is (f/i) → called as multiplying constant

C is (f + d) → called as additive constant

Important Points

For Annallatic Len

K = 100

C = 0

Explanation

Moveable hair method 

Stadia hair is not fixed but can be moved by means of micrometer screws.

•  The stadia hair can be moved in case of Movable hair method which is also known as subtense method.
• The intercept on leveling staff is kept constant and stadia hair interval is variable.
• The stall is provided with 2 vanes or targets fixed at a known distance apart.
• The variable stadia distance measured from this value, the required horizontal distance may be found out.
• It is a slow method as compared to other methods.

Additional Information 

Fixed hair method

• In this method distance between hairs is fixed
• If the stadia wires are fixed, this method is known as Fixed hair method.
• The intercept on leveling staff is variable and the stadia hair interval is fixed.
• The staff intercept value varies with its distance from the instrument, this is most commonly used in tacheometry  

Tangential hair method

• In the tangential hair method, the stadia hairs are not used.
• The readings being taken against horizontal crosshair.
• It is slower than the stadia hair method.

Distance from instrument location to staff is given by:

D = ks +c

Where, c is the additive constant and k is the multiplying constant.

\(k = \frac{f}{i}\)

c = f + d

where,

i = stadia interval = staff intercept = 2 mm

f = focal length = 250 mm

d = distance of the instrument axis from the centre of the object glass = 190 mm

\(k = \frac{{250}}{2} = 125\)

For tacheometric surveying:

In Tacheometric surveying by stadia method, Horizontal distance of the Staff from the optical centre of the objective is given by equation-

\(\mathbf{D}=\left( \frac{\mathbf{f}}{\mathbf{i}} \right)\mathbf{s}+\mathbf{(f+d)}\)

Where,

u = horizontal distance of the staff from the optical centre of the objective, f = focal length of the objective, i = stadia interval, and s = staff intercept

The equation can also be written as:

D = k × s + C

Where k = f/i is called the multiplying factor.

Explanation:

When staff is held vertically to the ground surface:

L = Ks cos θ + C

Now vertical distance

V = L sin θ

V = (Ks cos θ + C) sin θ = ( Ks Sin2θ )/2 + C sin θ 

Now horizontal distance

H = L cos θ

H = (Ks cos θ + C) cos θ

H = Ks cos 2θ  + C cos θ

Explanation

Moveable hair method 

• Stadia hair is not fixed but can be moved by means of micrometer screws.
• The intercept on leveling staff is kept constant and stadia hair interval is variable.
• The stall is provided with 2 vanes or targets fixed at a known distance apart.
• The variable stadia distance measured from this value, the required horizontal distance may be found out.
• It is the slow method as compared to other methods

Fixed hair method

• In this method distance between hairs is fixed
• The intercept on leveling staff is variable and stadia hair interval is fixed.
• The staff intercept value varies with its distance from the instrument, this is most commonly used in tacheometry  

Tangential hair method

• In the tangential hair method the stadia hairs are not used.
• The readings being taken against horizontal cross hair.
• It is slower than the stadia hair method.

Concepts:

Electronic distance measurement (EDM)

• Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves.
• EDM instruments are highly reliable and convenient pieces of surveying equipment and can be used to measure distances of up to 100 kilometers.
• They measure the length between two points, using phase changes that occur as electromagnetic energy waves travels from one end of the line to the other end.
• They have accuracy up to 1 in 10⁵.

Concept:

K = Multiplying Constant

C = additive constant

Anallatic lens is a special case in which k = 100 and c = 0. The type of lens used in anallatic telescope is a convex lens.

Horizontal distance, D = ks + c

Solution:

D = 1.5 × 100 + 0 = 150 m

Explanation

Moveable hair method 

• Stadia hair is not fixed but can be moved by means of micrometer screws.
• The intercept on leveling staff is kept constant and stadia hair interval is variable.
• The stall is provided with 2 vanes or targets fixed at a known distance apart.
• The variable stadia distance measured from this value, the required horizontal distance may be found out.
• It is the slow method as compared to other methods

Fixed hair method

• In this method distance between hairs is fixed
• The intercept on leveling staff is variable and stadia hair interval is fixed.
• The staff intercept value varies with its distance from the instrument, this is most commonly used in tacheometry  

Tangential hair method

• In the tangential hair method the stadia hairs are not used.
• The readings being taken against horizontal cross hair.
• It is slower than the stadia hair method.