Survey and Leveling -Teachers Training.pdf

Survey and leveling

2015.06.15

......? What is surveying?

,

,

,

Faculty of Agriculture-University of Ruhuna 2

....? What is leveling?

( )

( )


....?

-

,

-

- ,

, ,


.....?

- -

,

(cut and fill)


?

- Direct or Differential

leveling

- Tapes and

Graduated rods

- Trigonometric

Leveling

- Barometric

Leveling


-

Trigonometric

Leveling

V = S cos z

V = S sin

V = H tan

?


- Barometric

Leveling

?


- Direct Leveling

(Vertical

Height).

(Level Line) .

.


....

A1

A2

?

2.3 m 3.1 m

0.8 m

=250 m


?


..?


Use of A Frame A


.....? (Leveling Instrument)

- Dumpy level

- Auto level

- Tilting Level

- Theodolite

- Digital Auto Level

- Laser Level

- Tripod

- Staff gauge

- Staff bubble

- Change plate

- Filed note book


- Dumpy Level



- Tilting Level

- Auto Level


Suspended Compensation

Fixed Prism is

Used

- Theodolite


- Laser Level


- Tripod


- Staff gauge (Graduated Staff)


- Staff bubble


-

Change plate


- Filed note book


Important definitions used in Leveling - Vertical Line

- Horizontal Line

- Level Line

- Reference Level OR Datum

- -Bench Mark

- Reduced Level

- Line of Sight

- Height of Instrument OR Height of Collimation

- Back Sight

( ) - Fore Sight

- Intermediate Sight

- Turning Point


- Vertical Line


- Horizontal Line

-

Horizontal

Plane


- Level Line


(Reference

level or datum is a standard position or level

that measurements are taken from)

- Reference Level OR Datum


- -Bench Mark

(

)

- Fundamental Bench Mark-

- Survey Department

- Temporary Bench Mark


- Reduced Level

() Datum OR Reference Level

- Mean Sea Level-


- Line of Sight


- Height of Instrument OR Height of Collimation

-

Levelling Instrument-

Height of Collimation Or Height of the

instrument

The height to the horizontal line of sight which

passes though the optical center of the

telescope of the leveling Instrument above the

datum


- Back Sight

/ -Staff Gauge-


( ) - Fore Sight


- Intermediate Sight


- Change/Turning Point


IA IB

A1 A2 A3

A4 B1

B2 B3

Backsight (IA)

Intermediate sight

Backsight (IB)

Foresight (IB)

Foresight (IA)

Change point

Or turning point

R.L=220 m

- MSL

Line of sight

Height of instrument

(220 + h)

h


- -Ranging

Poles

-

- Staff gauge- - B.S

-

180


A1

A2

?

2.37 m 3.150 m

0.78 m


(BM)

-

- Bench Mark- - Staff gauge-

- B.S

-

180


A1

A2 ?

2.37 m 3.150 m

(BM)

R.L =250 m MSL

(Bench Mark)


- Bench Mark- -

Staff gauge- (Back

Sight- )

- Intermediate Sight-

- Fore

Sight-


R.L=250 m

MSL (BM)

2.91m 2.32 m 2.80 m 2.87 m 3.28 m 3.85 m

A1 A2

A3 A4

A5 A6

A1 A6


(Rise), (Fall)

- = (Positive

Value)

- = (Negative

Value)

(

)


-

Rise and Fall Method

BS

IS

FS

Rise

Fall

RL

/

Distance

Remarks

3.85 250 A1 (BM)

3.28 0.57 250.57 A2

2.87 0.41 250.98 A3

2.80 0.07 251.05 A4

2.32 0.48 251.53 A5

2.91 0.59 250.94 A6

BS-FS= Rises-Falls=Last RL-First RL

3.85-2.91 = (0.57+0.41+0.07+0.48)-0.59 = 250.94-250

0.94 = 1.53-0.59 = 0.94

0.94=0.94=0.94


-

Height of Collimation Method

BS

IS

FS

HC/HI

RL

/

Distance

Remarks

3.85 253.85 250 A1 (BM)

3.28 253.85 250.57 A2

2.87 253.85 250.98 A3

2.80 253.85 251.05 A4

2.32 253.85 251.53 A5

2.91 253.85 250.94 A6

BS-FS= Last RL-First RL

3.85-2.91 = 250.94-250

0.94 = 0.94


BS

FS

HC/HI

RL

/

Distance

Remarks

3.03 103.03 100.00 BM

3.86 103.03 99.17

2.60 101.77 99.17 TP1

4.53 101.77 97.24

4.22 101.46 97.24 TP2

6.16 101.46 95.30

6.43 101.73 95.30 TP3

4.44 101.73 97.29

3.85 101.14 97.29 TP4

2.96 101.14 98.18

5.11 103.29 98.18 TP5

3.30 103.29 99.99 BM


25.24 25.25 = 99.99-100.00 - 0.01 = -0.01


BS

FS

HC/HI

RL

/

Distance

Remarks

3.03 103.03 100.00 BM

3.86 103.03 99.17

2.60 101.77 99.17 TP1

4.53 101.77 97.24

4.22 101.46 97.24 TP2

6.16 101.46 95.30

6.43 101.73 95.30 TP3

4.44 101.73 97.29

3.85 101.14 97.29 TP4

2.96 101.14 98.18

5.11 103.29 98.18 TP5

3.30 103.29 99.99 BM


25.24 25.25 = 99.99-100.00 - 0.01 = -0.01

(Error of closure OR Misclosure)


1.5 km

0.8 km

1.0 km

1.9 km

0.5 km

A

E

D

C

B

20.00 m

IS=3.33

IS=2.32

IS=3.71

IS=1.47

BS=2.35

FS=2.37


BS

IS

FS

HC/HI

RL

/

Distance

Remarks

2.35 22.35 20.00 A (BM)

3.33 22.35 19.02 B

2.32 22.35 20.03 C

3.71 22.35 18.64 D

1.88 22.35 20.47 E

2.37 22.35 19.98 A


2.35 2.37 = 19.98-20.00 0.02 = 0.02

A

E

D

C

B

20.00 m

IS=3.33

IS=2.32

IS=3.71

IS=1.47

BS=2.35

FS=2.37

1.5

km

0.8

km

1.0

km

1.9

km

0.5

km


- Instrumental Errors

- Observational Errors

- Natural

Errors


- Instrumental Errors

- Residual Collimation Error

- Two Peg Test-

- Cross Hair Parallax Error

- Staff Graduation Error


- Observational Errors

- Systematic or Cumulative Errors -

- Random Errors

-Staff is not properly extended or assembled

, 3.538 3. 583


-

Natural Errors

-


Line of Sight OR Collimation Error occurs when telescope is not in a horizontal position

Keeping the horizontal distance of the backsights and

foresights at each instrument position equal will cancel

the error

Where observational distances are unequal, the error

will be proportional to the difference in distance

The collimation error will not cause errors in differential

leveling as long as backsight and foresight distances

are balanced

Two peg test (Horizontal Collimation Test)is used to

determine the error

TWO PEG TEST HORIZONTAL COLLIMATION TEST

Horizontal Collimation Test

Tachometry- Measurement of distance using

Stadia

The use of level for measuring the distance

Read the figure where the stadia lines cut the

staff

Calculate the difference (staff intercept(s))

Staff intercept multiplied by 100 give the

distance from the center of the instrument to the

staff position


When external focusing

telescope is used. Now these

types of telescopes are not

used and objective lence is

fixed The objective lens of an

internal focusing telescope

(the type now used in

surveying instruments)

remains fixed in position,

while

a movable negative-focusing

lens between the objective

lens and the plane of the

crosshairs changes directions

of the light rays.As a

result,the stadia constant (C)

is so

small that it can be assumed

equal to zero and drops out

of Equation (5.1).Thus


Diagram shows the principle when external focusing telescope is used. Now these

types of telescopes are not used. The objective lens of an internal focusing telescope

(the type now used in surveying instruments) remains fixed in position, while a

movable negative-focusing lens between the objective lens and the plane of the

crosshairs changes directions of the light rays. As a result, the stadia constant (C) is

so small that it can be assumed equal to zero

Most of

instruments

K is 100

f

D

C

E

B S

c

e

b

SK)Si

f(D

i)(cei

f

S

D

ce

Ab

CE

AB

1

Modern telescopes are made so

that f and i to be 100

Distance between stadia lines (S)

multiplied by 100 gives the

distance

A

-Leveling Practical

Profile Leveling

Measurement of height in two positions

Area Leveling

Contouring

Direct

Grid


Documents

Survey and Leveling -Teachers Training.pdf