Tacheometry

INTRODUCTION TO TECHEOMETRY

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

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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 Sin α 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 Sin α 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