3. Principles
Incline Sight With The Staff Vertical
dH
hi
s = the staff intercept AB
h = the length of the centre hair reading from the staff base
V = the vertical component XY, the height of the centre hair reading above
(or below) the instrument axis
D = the length of the line of sight IX
H = the horizontal distance required.
hi = instrument height
4. Publication formula
To obtain Slope distance;
distance
So,
D
= Ks + C
= K(A’B’) + C
But, A’B
= ABCos θ atau sCos θ
So
D
= KABCos θ + C
D
= Ks.Cos θ + C
To obtain Horizontal Distance and Vertical Distance ;
H = DCos θ
= Ks.Cosθ 2 + C.Cos θ
V = Dsin θ
= Ks.Cos θ.Sin θ + C.Sin θ
= ½ (Ks.Sin 2θ ) + C.Sin θ
Determination First Reduced Level Station ;
RLstn= RLTBM – hi ± V – h
Determination Difference Height ;
dH = hi ± V – h
The reduced level of the instrument position I plus the difference in height
equal the reduced level of the staff position S. Therefore:
R.L.s = R.L.I + hi ±
V–h
5. Cycle Diagram
Where
D = Distance
K & C = constant (if not given assume K = 100 & C = 0)
S = staff intercept
H = horizontal distance
V = vertical distance
θ = zenith angle (positive for angles of the elevation,
negative for angles of the depression)
hi = the height of instrument (always positive)
h = the centre hair reading (always negative)
6. Work procedure EXAMPLE RESULT PRACTICAL 2 - TACHEOMETRY BOOKING FORM
(The stadia system Incline Sights With The Staff Vertical)
Inst. Stn. Sta Horizontal
and Ht. of ff
angle, HL
inst. axis stn
Horizontal
angle, HR
Average
horizontal
angle
Vertical
angle, V
Upper
stadia
Middle
stadia
Lower
stadia
Text
A
B
SETTING
SETTING
105015’30” 285015’30”
95 11’25”
1.205
1.080
0.950
(1.455 m)
C
155010’36” 335012’30” 335011’33” 90012’20”
1.050
1.030
1.010
C
A
SETTING
SETTING
335011’33” 155011’33”
85016’25”
1.345
1.145
0.945
(1.305 m)
D
45020’26”
225032’30” 225026’28” 88018’10”
1.250
1.100
0.950
D
C
SETTING
225026’28”
SETTING
45026’28”
90010’20”
1.530
1.230
0.930
(1.250 m)
E
345005’26” 165002’30” 165003’58” 92045’00”
Text
0.855
0.755
0.655
E
D
SETTING
SETTING
165003’58” 345003’58”
89035’00”
1.855
1.605
1.355
(1.256 m)
B
265045’55”
85040’05”
85025’40”
1.055
0.755
0.455
B
E
SETTING
85043’00”
SETTING
265043’00”
90016’35”
Text
1.355
1.055
0.755
(1.355 m)
A
285015’26” 105012’30” 105013’58” 90015’50”
1.555
1.305
1.055
0
Text
Text
85043’00”
Remarks
GIVEN REFERENCE
BERING AB =
105015’30” (25m)
7. •
•
•
•
GIVEN THE TBM (Temporary bench mark) – Stn A & B
READING VERTICAL ANGLE BELONG THE SITUATION
TRAVERSE METHOD
TAKE TOPOGRAPHY ITEMS (Tree, Building)
Refer the plan
AB
H=
V=
S upper=
S middle=
S lower =
AC
H=
V=
S upper=
S middle=
S lower =
BA
H=
V=
S upper=
S middle=
S lower =
CA
H=
V=
S upper=
S middle=
S lower =
BE
H=
V=
S upper=
S middle=
S lower =
ED
H=
V=
S upper=
S middle=
S lower =
EB
H=
V=
S upper=
S middle=
S lower =
CD
H=
V=
S upper=
S middle=
S lower =
DC
H=
V=
S upper=
S middle=
S lower =
DE
H=
V=
S upper=
S middle=
S lower =
8. Practical 2
E Tree 2
H=
V=
S upper=
S middle=
S lower =
D Tree 1
H=
V=
S upper=
S middle=
S lower =
A Building 1
H=
V=
S upper=
S middle=
S lower =
A Building 2
H=
V=
S upper=
S middle=
S lower =
C Tree 3
H=
V=
S upper=
S middle=
S lower =
C Building 3
H=
V=
S upper=
S middle=
S lower =
C Building 4
H=
V=
S upper=
S middle=
S lower =
9. Calculation – example for field book
Inst. Stn.
and Ht.
of inst.
axis
Staff
stn.
B
A
(155 m)
Horizontal
angle, HL
Horizontal
angle, HR
Average
horizontal
angle
Vertical
angle, V
Upper stadia
Middle
stadia
Lower
stadia
Remarks
GIVEN REFERENCE
BERING AB =
b1
Building 1
b2
Building 2
C
A
b3
C
(155 m)
Building 3
b4
Building 4
tree3
Tree 3
D
