linear measurement and levelling practical report

7/23/2019 LINEAR MEASUREMENT AND LEVELLING PRACTICAL REPORT

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JOMO KENYATTA UNIVERSITY

OF

AGRICULTURE AND

TECHNOLOGY

Civil, Construction & Environmental Engineering Department.

SURVEY PRACTICA REP!RT !" I"EAR #EASURE#E"T A"D EVEI"$.

%n YEAR 'IRST SE#ESTER.

ECE %%(%.

SURVEY ).

SU*#ITTI!" DATE+)-)%-%(). PREPARED *Y !D/IA#*! *RIA" !D/IA#*!.

$R!UP #E#*ERS.

).!D/IA#*! *RIA" !D/IA#*! E"%)0(1%20%()1

%."YA3U"DI 3EVI" SIR! E"%)0(1%40%()1

4.#UI$AI *E"S!" #5AT/I E"%)0(1%(0%()1

1."DEDA ERIC $A"D/I E"%)0(0%()1

."YA"$EC/I "IC!DE#US !"DU#A E"%)0(1%0%()1

6."YA#*A3A RYA" E"%)0(1%10%()1

2.S/ARIA E"!C/ TI"$A E"%)0(1440%()1

7.*ARASA DA"IE E"%)0%760%()1



A.OBJECTIVES.

1.To familiarize and be able to work with the various linear measuring equipment .

2.To familiarize and be able to work with the various levelling equipment .

3.To be able to use the practical knowledge learnt in 1 and 2 above to carry out

linear measurement and levelling on a given site.

4.To prepare a topographical map of the site.

B.INTRODUCTION.

y the various methods of determining distance the most accurate and common

method is the method of measuring distance with a chain or tape is called !haining.

"or work of ordinary precision a chain is used. ut where great accuracy is required

a steel tape is invariably used. The term chaining was originally applied to measure

of distance with a chain. The term chaining is used to denote measuring distance

with either chain or tape. #n the process of chaining$ The survey party consists of a

leader %the surveyor at the forward end of the chain& a follower %the surveyor at therare end of the chain and an assistant to establish intermediate points& .The

accuracy to which measurement can be made with chain and tape varies with the

methods used and precautions e'ercised. The precision of chaining. "or ordinary

work$ ranges from 1(1))) to 1(3)$))) and precise measurement such as aseline

may be of the order of 1)))))). *n the other hand levelling is an operation

required in the determination or more strictly $the comparison $of heights of points

on the surface of the earth. The quali+cation is necessary since the height of one

point can be given only relative to a plane$ this plane is called a datum and in

topographical work the datum used is the mean sea level since it makes comparison

of sea level possible.

#n this practical we used the knowledge acquired in class and that from theintroductions made by the ,-,# practical technicians to carry out linear

measurements in our site. The surveyors chain and drag tape were the main

instruments used for linear measurements. /evelling process in the site was started

on a benchmark% 100).3)m *& which was available within the site . umpy

level was used for this practical although we were introduced to other types of

levels.

)mm allowable error was issued for the levelling process.

!.#5T678-5T.

9e used the following instruments to carry out linear measurements and levellingfor our site:

-LINEAR MEASUREMENT INSTRUMENTS.

1.urveyor;s !hain.

2.!haining rrows.

3.rag Tape.



4.*ptical quare.

0.4 6anging 6ods.

-Levelling equipments.

1. umpy level

2. !hange plate.

3. /evelling sta<.

4. ubble tube.

0.=egs

>.urveyors tape.

=icture showing the group;s practical site :

D.METHODOLOGY.

1. Reconnaissance.

The survey site was issued on *ctober 2)th 2)10 the group visited the site on 20th

*ctober 2)10 .9here we:

1.#dentifed main features on our site i.e. equally spaced planted trees

2.#denti+ed the di<erent kinds of obstacles to the survey process .

3.#denti+ed the nature of our site i.e. gentle sloped land.

4. sketch of the plan was then made containing the identi+ed features andobstacles.

2.Linear Measre!en".

1.The four lengths of the site were accurately measured using a drag tape andrecorded. 9hile carrying out measurements it was ensured that the tape wasstraight $taut and lying on the ground.



2.The longest diagonal across the site was identi+ed and a surveyors chain laidacross this diagonal. 6anging was done to ensure the chain running along thediagonal was straight .*nce the chain was con+rmed to be straight a chainingarrow was +'ed at its end in place of the ranging rod.

3."eatures near this diagonal were mapped alternatively by ties and o<sets. The

optical square was used to erect o<sets from the baseline while ties wereconstructed from 2 di<erent points on the chain using the surveyors tape.

8any features were marked up to the end one chain length .istances of thefeatures along the baseline and from the baseline was also measured and bookedappropriately.

4.The chain was then dragged until the opposite corner at the end of the diagonal.6anging was again done with one member at the end of the chain to ensure the itwas straight. *nce straight a chaining arrow was then pinned in place of the rangingrod.

0.8apping of points was resumed up to the end of the second chain length

% also end of the longest diagonal& and booked appropriately>.ome features were also mapped from the boundaries of our areas by erecting ofo<sets$ the horizontal distances between trees in organized rows was alsomeasured and recorded.

5. wall obstacle was encountered when measuring one of the lengths howeverthe method of repeated alignment was used to mitigate this error

#.LEVELLING $ROCESS.

1.The area was divided at 1)m intervals using pegs along the longest side as thearea was generally $marking of grid intervals started at a distance m from theupper region as that region was generally ?at.

2. istance of 1)m was measured using a surveyors tape from the pegs along thelongest side into the site$ pegs were +'ed at distances of multiples of 1) up to theopposite longest side of the area. This way the area had been divided into gridsquares of 1)m length.

3.The level was set up in the upper region close to the bench@mark. levelling sta<was placed on the bench@mark$ temporary adAustments were made to the level andthe sta< reading at the benchmark read and recorded as back@sight.

5: This +rst station was still outside the grid area.

4. spot height was taken at the upper region as a representative of the generally

?at upper area.

0.*n peg on the edge of the grid line was removed and a levelling sta< paced atthat spot this level reading was taken as a foresight.

>.The level was then moved into the grid area$ temporary adAusted and the readingof the stu< taken again as back@sight.

.The level stu< was then removed at this point and the peg replaced $pegs insidethe grid area were removed each time being replaced by a levelling stu< and the



reading made on this levelling stu< were booked as inter@sights. fter every readingof the level sta< the pegs were inserted back in place.

. last reading was taken as foresight and the instrument moved to a thirdstation $the levelling process repeated and closed on afore@sight at the corner of thesite.

B./evelling was again done from this last point to the bench@mark. uring the ?y@back$sta< readings were taken on the same initial points only the instrumentposition was changed.

These readings were booked separately on a fresh page.

5: -very time a level stu< was used it was placed on top of a change plate and abubble tube was used to ensure it was perpendicular to the ground .6eadings wereonly made when the sta<@man indicated that the level stu< was perpendicular.

t least 2 members of the group con+rmed the main bubble formed a complete C7Dbefore any stu< reading was taken.

%.$RE$ARATION O&' TO$OGRA$HICAL MA$.

1.n appropriate scale 1:2)) was chosen and used to plot all lengths with theappropriate dimensions as per the revised sketch.

2.ll features in the sketch were appropriately represented on the map $in the casewhere abbreviations were used e'planation were given in the legend.

3.ll reduced levels were represented on the map . 9hen representing the reducedlevels sketch 3%attached& was used to identify points @/ on the map whose reducedlevels had been booked book .=oints booked were The highest and lowest reducedlevel were identi+ed and vertical interval was decide i.e. ).0m

E.RESULTS .

LINEAR MEASUREMENTS.

ll linear measurements were denoted on the revised sketch and others included inthe +led notes attached.

LEVELLING.

BAC(SIGHT INTERSIGHT &ORESIGHT REMAR(S

1.3B0m enchmark1.)1m 1.43m %!=&

1.1>1m 1.113m !1.))3m 1.23m -1.410m "1.4B3m ,1.>20m E

1.1)3m 1.0)2m #%!=&



1.>0m F1.>>m G

1.20)m /

&LY BAC(.

!G#,ET #5T-6#,ET "*6-#,ET 6-86G1.423m /

1.4m G 1.43m F

1.>Bm 1.2>0m # %!=&1.03)m E1.44m ,1.4))m "1.2>0m -).B0)m 1.)Bm !1.14m

1.>Bm 1.)33m %!=&1.20)m -5!E86G

6-#5, *" /-H-/ T"" T =*T E-#,ETI1.2Bm.

&.DATA ANALYSIS

BAC(SIG

HT

INTERSIG

HT

&ORESIG

HT

RISE &ALL REDUCED

LEVELS

REMAR(S

1.3B0m 100).3)

m

enchmar

k1.)1m 1.43m ).44m 104B.B22

m

%!=&

1.1>1m ).144m 104B.

m

1.113m ).)4m 104B.2>

m

!

1.))3m ).11)m 104B.B3>m

1.23m ).2)m 104B.>0>

m

-

1.410m ).132m 104B.024

m

"

1.4B3m ).)m 104B.44>

m

,



1.>20m ).132m 104B.314

m

E

1.1)3m 1.0)2m ).123m 104B.43

m

#%!=&

1.>0m ).02m 104.>0

m

F

1.>>m ).))1m 104.>4

m

G

1.20)m ).42>m 104B.2B)

m

/

JI3.010

m

@

J"I4.0B0

m

J"I4.0B0

m

J6

).)m

@

J"1.

m

J"1.

m

104B.2B)

m

@

104B.B22

m@1.)m @1.)m

&LYBAC(.

BAC(SIG

HT

INTERSIG

HT

&ORESIG

HT

RISE &ALL REDUCEDLE

VELS

REMAR(

S

1.423m 104B.)BBm /1.4m ).424

m

104.>0m G

1.43m ).))4

m

104.>Bm F

1.>Bm 1.2>0m ).0

m

104B.20m # %!=&

1.03)m ).1>

m

104B.420m E

1.44m ).)0>

m

104B.41m ,

1.4))m ).)4

m

104B.000m "

1.2>0m ).130

m

104B.>B)m -

).B0)m ).310

m

100).))0m

1.)Bm ).14

m

104B.0m !

1.14m ).)4B

m

104B.)m

1.>Bm 1.)33m ).114

m

104B.B22m %!=&

1.20)m ).44 100).3)m -5!E8



m 6G

J 4.1Bm

@J3.04m

J3.04m J1.B2

m

@

J).>21

J).>2

1

1.21m 1.21

m

G.CONCLUSION.

9hen carrying out linear measurements the length of the chain was measured

using the drag tape this length was found to be 3)m i.e. there chain had no lose in

length however sag$ tension $slope corrections could not be applied as instruments

required for measurement of temperature $tension $and vertical angles were not

provided.

8easurement values were recorded by 2 group members to reduce error inbooking$ when these values were con+rmed they were found to match.

8ethods of linear measurement such as the use of -8 and ground catenary was

not employed .

fter construction of grid lines not all points pegged were levelled$ consecutive

pegs which from observation seemed to on the same ground level were ignored

during levelling.

-ach group member was involved in all levelling activities alternatively and every

member was able to at one time $read sta< readings$ holding the survey sta< $level

the level among other activities. The levelling process was also started and ended on a benchmark.

The reduced levels obtained during the ?y back only varied slightly with the

reduced levels of the same points taken during the survey process$

I.RECCOMMENDATIONS.

1.=racticals should be in smaller groups if possible or the number of instruments per

group increased.

2.ite survey areas should be of much more rugged terrain so that many survey

methods are involve in chaining or levelling

linear measurement and levelling practical report

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