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Solution: Trig Leveling
Problem (1)
A TSI is set up 5.41' over point Q whose elevation is 745.39'. The following readings are taken:
| Point | Horizontal angle |
Vertical angle |
Slope distance |
| 101 | 0°00'00" | 4°24'10" | 145.25' |
| 102 | 39°56'15" | -6°00'25" | 89.32' |
| 103 | 79°05'45" | -2°58'30" | 118.95' |
The reflector height in each case was 5.64'. The instrument and reflector heights were measured with the same cloth tape.
What are the horizontal distances to and elevations of the observed points? Compute values to 0.01'.
Solution
To use the equations from Chapter D. Stadia, each vertical angle must be converted to a zenith angle.
Point 101
Because the curvature and refraction is so small, it can be ignored for the other horizontal distances.
Because the curvature and refraction is so small, it can be ignored for the other vertical distances.
Point 102
Point 103
Solution
| Point | Horiz dist | Elevation |
| 101 | 144.82 | 756.31 |
| 102 | 88.83 | 735.81 |
| 103 | 118.79 | 738.99 |