Join 60,000+ competitive exam aspirants
Difference between upper and lower stadia reading on staff it gives __________
stadia slope
stadia coordinate
stadia intercept
staff intercept
staff intercept
In tacheometry, the difference between the upper stadia hair reading and the lower stadia hair reading taken on a leveling staff is known as the staff intercept (s). It represents the height of the staff segment intercepted between the top and bottom stadia lines of the diaphragm.
In tacheometry, the difference between the upper stadia hair reading and the lower stadia hair reading taken on a leveling staff is known as the staff intercept (s). It represents the height of the staff segment intercepted between the top and bottom stadia lines of the diaphragm.
s=SupperтАЛтИТSlowerтАЛ тАФ Staff intercept formula
D=kтЛЕs+c тАФ Horizontal distance equation in tacheometry (where k is multiplying constant, c is additive constant)
When viewing a leveling staff through the telescope of a tacheometer, the reticle contains two horizontal cross-hairs equidistant from the central hair (the upper and lower stadia hairs). The light rays passing through these hairs subtend a fixed angle, making the intercepted length on the distant staff directly proportional to the horizontal distance from the instrument to the staff.
The standard value of the multiplying constant (k=f/i) for a tacheometer is usually 100.
The standard value of the additive constant (c=f+d) for an anallatic lens system is 0.
Eliminates the need for chaining or taping in rough or inaccessible terrain.
Allows rapid measurement of horizontal distances and vertical elevations simultaneously.
Less precise compared to precise chaining or modern electronic distance measurement (EDM).
Measurement errors increase with larger sights due to difficulty in reading the staff.
Topographic surveying in hilly or broken terrain.
Contouring, location survey, and reconnaissance for route selection.
Option A (stadia slope) refers to the angle of inclination of the sight line, not the reading difference.
Option B (stadia coordinate) is an invalid term in tacheometry.
Option C (stadia intercept) is commonly used loosely in general talk, but technically the intercept measured on the physical leveling staff is specifically termed the 'staff intercept'.
D is correct тАФ The difference between the upper and lower stadia hair readings on a leveling staff gives the staff intercept.
Remember that for an anallatic telescope, k=100 and c=0, simplifying the distance formula directly to D=100s when the line of sight is horizontal.