Apply Eqs. 8 and 9 successively to obtain the elevations recorded in the accompany-
ing table.Point BS, ft(m) HI, ft(m) FS, ft(m) Elevation, ft (m)
BM42 2.076(0.63) 182.558(55.64) 180.482(55.01)
TPl 3.408(1.04) 177.243(54.02) 8.723 (2.66) 173.835(52.98)
TP2 1.987(0.61) 169.404(51.63) 9.826 (2.99) 167.417(51.03)
TP3 2.538(0.77) 161.476(49.22) 10.466 (3.19) 158.938(48.44)
TP4 2.754(0.84) 155.960(47.54) 8.270 (2.52) 153.206(46.70)
BM43 11.070 (3.37) 144.890(44.16)
Total 12.763(3.89) 48.355 (14.73)
- Verify the result by summing the backsights and foresights
Substitute the results in Eq. 10: 144.890 - 180.482 = 12.763 - 48.355 = -35.592.
STADIA SURVEYING
The following stadia readings were taken with the instrument at a station of elevation
483.2 ft (147.28 m), the height of instrument being 5 ft (1.5 m). The stadia interval factor
is 100, and the value of C is negligible. Compute the horizontal distances and elevations.Point Rod intercept, ft (m) Vertical angle
1 5.46(1.664) +2°40' on 8 ft (2.4 m)
2 6.24 (1.902) +3°12' on 3 ft (0.9 m)
3 4.83(1.472) -1°52' on 4 ft (1.2m)Calculation Procedure:- State the equations used
in stadia surveying
Refer to Fig. 9 for the notational sys-
tem pertaining to stadia surveying.
The transit is set up over a reference
point O 9 the rod is held at a control
point TV, and the telescope is sighted
at a point Q on the rod; P and R rep-
resent the apparent locations of the
stadia hairs on the rod.
The first column in these notes
presents the rod intercepts s, and the
second column presents the vertical
angle a and the distance NQ. Then FIGURE 9. Stadia surveying.
Line of sight•Rod