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Stadia method can also be known as __________
Fixed hair method
Movable hair method
Tangential method
Both A and B
Both A and B
The stadia method is the most common system of tacheometry in which a reticle with stadia wires is used to determine distances and elevations. Depending on whether the stadia hair interval is kept constant or variable, it is classified into the fixed hair method and the movable hair method. Therefore, the stadia method encompasses both the fixed hair and movable hair methods.
The stadia method is the most common system of tacheometry in which a reticle with stadia wires is used to determine distances and elevations. Depending on whether the stadia hair interval is kept constant or variable, it is classified into the fixed hair method and the movable hair method. Therefore, the stadia method encompasses both the fixed hair and movable hair methods.
D=kтЛЕs+C тАФ Tacheometric distance formula where D is horizontal distance, k is multiplying constant (ifтАЛ), s is staff intercept, and C is additive constant (f+d)
k=ifтАЛ тАФ Multiplying constant of the tacheometer
C=f+d тАФ Additive constant of the tacheometer
In the fixed hair method, the distance between the top and bottom stadia hairs is kept constant, and the staff intercept varies with distance. In the movable hair method (subtense method), the staff intercept is kept constant between two targets, and the distance between the stadia hairs is varied using micrometer screws until they coincide with the targets.
The stadia method is a branch of tacheometry using diaphragms with two horizontal stadia hairs.
In the fixed hair method, distance is determined by reading the variable staff intercept s for a known stadia interval i.
In the movable hair method, the distance between horizontal hairs i is varied and measured using a micrometer screw while keeping staff intercept s constant.
The tangential method does not use stadia hairs; instead, vertical angles to two targets on the staff are measured.
Fixed Hair Method: Fast, simple, and standard method widely used in field surveying.
Movable Hair Method: Can be used over very long sights where staff readings become difficult to read.
Fixed Hair Method: Sights are limited by the readability of the staff graduations at long distances.
Movable Hair Method: Requires expensive and complex instruments equipped with micrometer screws, making it prone to mechanical wear.
Topographic mapping and contouring in difficult terrains.
Location surveys for roads, railways, and reservoirs.
| Feature | Fixed Hair Method | Movable Hair Method |
|---|---|---|
Stadia Hair Interval (i) | Constant / Fixed | Variable |
Staff Intercept (s) | Variable | Constant / Fixed |
Measurement Technique | Direct reading of intercept on staff | Micrometer screw adjustment of hair spacing |
For an anallatic lens, the additive constant C=0 and multiplying constant k=100.
Option C (Tangential Method) is incorrect because it relies on measuring vertical angles to two vanes at a known distance on a staff without using stadia wires.
D is correct тАФ The stadia method includes both the fixed hair method and the movable hair method based on whether the stadia hair spacing is kept constant or adjusted.
Remember that while stadia methods require stadia hairs, the tangential method requires NO stadia hairs at allтАФonly an ordinary transit theodolite measuring vertical angles.