Tacheometry +part 2
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The document discusses tacheometry, which uses a theodolite fitted with a stadia diaphragm to measure distances. It describes the key components of tacheometry including the tacheometer, stadia rod, and stadia interval. The document explains that tacheometric distance (D) can be calculated using the formula D=Ks+C, where K is the multiplying constant, s is the stadia interval, and C is the additive constant. It also provides methods for determining the tacheometric constants K and C, including direct measurement and computation from multiple measured distances. Examples of solving tacheometry problems involving distance, elevation, and reduced level calculations are given.
Tacheometry +part 2
- 1. BY ---- MOHIT DUREJA
- 2. BY ---- MOHIT DUREJA
- 3. BY ---- MOHIT DUREJA
- 4. INSTRUEMENT USED IN TACHEOMETRY 1) TACHEOMETER • IT IS A TRANSIT THEODOLITE FITTED WITH A STADIA DIAPHRAGAM. • THE STADIA DIAPHRAGAM CONSIST OF ONE STADIA ABOVE AND OTHER AN EQUAL DISTANCE BELOW THE HORIZONTAL CROSS HAIR BY ---- MOHIT DUREJA
- 5. DIFFERENT TYPES OF DIAPHRAGAM CROSS HAIR DIAPHRAGAM STADIA HAIR DIAPHRAGAM BY ---- MOHIT DUREJA
- 6. 2) STADIA ROD • For small sights ordinary leveling staff is used. It has a least count of 5mm. • For long sight stadia rod is used. The least count is 5mm or 10mm cont… INSTRUEMENT USED IN TACHEOMETRY BY ---- MOHIT DUREJA
- 7. Requirement/ Characteristics of Tacheometer • The value of multiplying constant should be 100 • The central horizontal hair must be exactly mid way between the other two horizontal hair • The value of additive constant should be zero. • In order to have bright image the aperture of objective should be 35 to 45 mm. BY ---- MOHIT DUREJA
- 8. METHODS OF TECHEOMETRY BY ---- MOHIT DUREJA
- 9. STADIA INTERVAL 0R STAFF INTERCEPT (S) S=(12.38 - 11.98) S= 0.40 M BY ---- MOHIT DUREJA
- 10. BY ---- MOHIT DUREJA
- 11. :-The stadia method is based on the principle that the ratio of the perpendicular to the base is constant in similar isosceles triangles D BY ---- MOHIT DUREJA
- 12. D= K s + C WHERE; K= MULTIPLYING CONSTANT C = ADDITIVE CONSTANT TACHEOMETRIC CONSTANT Multiplying constant is usually taken as 100 Additive constant is taken as zero(0) There values are generally provide by manufacturers BY ---- MOHIT DUREJA
- 13. DETERMINATION OF STADIA CONSTANT 1) BY DIRECTLY MEASURE FROM THE INSTRUMENT D= f s + (f+d) i f BY ---- MOHIT DUREJA
- 14. 2) BY COMPUTATION D1= f S1 + (f+d) i D2= f S2 + (f+d) i D3= f S3 + (f+d) i …………..1 …………..2 …………..3 SOLVE EQ. 1 & 2 EQ. 2 & 3 EQ. 3 & 1 And find exact value by their mean f i (f+d) = ? = ?K C BY ---- MOHIT DUREJA
- 15. Q .) Two distance of 90m and 250m were accurately measured out and the intercepts on the vertical were 0.895 & 2.495m respectively. Calculate Tacheometric constant. BY ---- MOHIT DUREJA
- 16. Q. With telescope horizontal, the readings taken by upper and lower wires were 3.840 and1.060 m. Find the horizontal distance and elevation of staff station if the RL of instrument axis is 341.540m. The central hair reading was 2.450. (K=100, c=0.4) BY ---- MOHIT DUREJA
- 17. Distance and elevation formula with inclined sight D=K Cos α S Cos α + C Cos α V=K Sin α S Cos α + C Sinα D= K S + C ……from Case 1 RL of staff station (M)= RL of Inst. Axis + (V-h) D α =ANGLE OF ELEVATION BY ---- MOHIT DUREJA
- 18. Distance and elevation formula with inclined sight D=K Cos α S Cos α + C Cos α V=K Sin α S Cos α + C Sinα D= K S + C ……from Case 1 RL of staff station (M)= RL of Instrument Axis - (V+h) α =ANGLE OF DEPRESSION BY ---- MOHIT DUREJA
- 19. Q.) A tacheometer was set up at A and the readings on staff held vertical at B were 1.215, 1.825, 2.435, the line of sight at elevation of 6ᴼ30’. Calculate distance between them and RL of point B if the RL of the sight is 350.700 m. ( K=100 ,C=0.35) BY ---- MOHIT DUREJA
- 20. Tangential method • Stadia hairs are not used to bisect the staff. • Two vanes are fixed at a constant distance apart on the staff. • Each vane is bisected by the cross hair. • Staff reading and vertical angle corresponding to each vane is measured and recorded. D S V
- 21. Case 1: When observed angles are angle of elevation
- 22. Case 2: When observed angles are angle of Depression
- 23. Case 3: When one angle is angle of Depression and other is elevation