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INTRODUCTION
LEVELLING
Levelling or leveling is the measurement of geodeticheightusing
a levelling instrument and
alevel staff. Common levelling instruments include the spirit
level, the dumpy level, andthe laser level. The two main types of
levelling are single-levelling and double-levelling. In
double-levelling, a surveyor takes two foresights and two
backsights and makes sure the
difference between the foresights and the difference between the
backsights are equal, thereby
reducing the amount of error. ouble-levelling costs twice as
much as single-levelling.
!n automatic level or dumpy was commonly used in surveying work
to transfer, measure or to
test levels. It is used to gather and"or to transfer a known
level to any unknown level. This survey
work is a common practice and basic procedure during site
surveys, building construction or
other civil constructions.
TRAVERSE
Traverse is a method in the field ofsurveyingto establish
control networks. It is also used in
geodetic work. Traverse is a series of surveys points whose
relative positions are determined by
measured distances and directions between each set of
consecutive points. The measured
distances are usually referred to as #course$ or #leg$. The
survey points are called #traverse
stations$, or angle points.
TACHEOMETRY
Tacheometry is a system of rapid surveying,by which the
positions, both hori%ontal and vertical,
of points on the earth surface relatively to one another are
determined without using a chain or
tape or a separate levelling instrument.
The introduction of tacheometry, in which, instead of the pole
formerly employed to mark a
point, a staff similar to alevel staff is used. This is marked
with heights from the foot, and is
graduated according to the form of tacheometer in use.
Thea%imuthangle is determined as
formerly. The hori%ontal distance is inferred either from the
vertical angle included between two
well-defined points on the staff and the known distance between
them, or by readings of the staff
indicated by two fi&edstadiawires in the diaphragm 'reticle(
of thetelescope. The difference of
height is computed from the angle of depression or elevation of
a fi&ed point on the staff and the
hori%ontal distance already obtained. Thus all the measurements
requisite to locate a point both
vertically and hori%ontally with reference to the point where
the tacheometer is centred are
determined by an observer at the instrument without any
assistance beyond that of a man to hold
the staff.
http://en.wikipedia.org/wiki/Geodetic_systemhttp://en.wikipedia.org/wiki/Heighthttp://en.wikipedia.org/wiki/Level_staffhttp://en.wikipedia.org/wiki/Spirit_levelhttp://en.wikipedia.org/wiki/Dumpy_levelhttp://en.wikipedia.org/wiki/Laser_levelhttp://en.wikipedia.org/wiki/Surveyinghttp://en.wikipedia.org/w/index.php?title=Control_networks&action=edit&redlink=1http://en.wikipedia.org/wiki/Surveyinghttp://en.wikipedia.org/wiki/Level_staffhttp://en.wikipedia.org/wiki/Azimuthhttp://en.wikipedia.org/wiki/Stadiumhttp://en.wikipedia.org/wiki/Reticlehttp://en.wikipedia.org/wiki/Telescopehttp://en.wikipedia.org/wiki/Geodetic_systemhttp://en.wikipedia.org/wiki/Heighthttp://en.wikipedia.org/wiki/Level_staffhttp://en.wikipedia.org/wiki/Spirit_levelhttp://en.wikipedia.org/wiki/Dumpy_levelhttp://en.wikipedia.org/wiki/Laser_levelhttp://en.wikipedia.org/wiki/Surveyinghttp://en.wikipedia.org/w/index.php?title=Control_networks&action=edit&redlink=1http://en.wikipedia.org/wiki/Surveyinghttp://en.wikipedia.org/wiki/Level_staffhttp://en.wikipedia.org/wiki/Azimuthhttp://en.wikipedia.org/wiki/Stadiumhttp://en.wikipedia.org/wiki/Reticlehttp://en.wikipedia.org/wiki/Telescope
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METHODOLOGY
LEVELLING
)( *e started the leveling process from the given benchmark
point.
+( The !uto-level was set up accordingly by fi&ing the
bubble method.
( enchmark is the first back-sight and staff was placed there.
The well-balanced !uto-
level was shooting e&actly to the staff and first benchmark
reading was obtained.( Then the staff was moved to the ne&t
point referred as the front-sight, the reading was
obtained as the first front-sight.'the distance was
fi&ed(
/( Then the !uto-level was moved and shoot to the previous staff
position and reading
obtained was the backside reading. Then the staff was moved to
ne&t point and referred
as the front-sight.
0( This step was repeated until we arrived at the last point
which was fi&ed by the lecturers.
1( Then we repeat again but in reverse direction until we met
the benchmark again.2( !ll the arithmetical check, errors and
misclosures was computed.
TRAVERSE
)( *hen the area of traversing was described to us, firstly we
walk around the location and
develop a simple sketch, in order to assist us in making the
e&act plan.
+( Then we mark the traverse location by spraying a nail onto
the ground. *e manage to
give the area into two four sided polygon.( ! tripod was placed
above the first point and a plumb line, 'a piece of lead with a
tapering end hung to the base of the tripod pointing e&actly
on the nail hanging by a thin
thread(, plumb bob was placed at the point of convergence of the
legs of the tripod, and
made to drop freely onto the top of the nail.
( To set up the theodolite properly we refer to the bubble
ad3ustment method./( 4ame procedures are repeated to set up the
theodolite at each station.
0( !fter set up was done, the recording are started, we were
using the face-to-the-left
traversing method. Therefore from our first point, we will
measure the angle from right to
the left which was the last and the second point.1( Then we hold
the reading in theodolite and moved to the second point.
2( The method is repeated until all the internal angle of our
polygon was measured.
5( *e supposed to measure the distance between points but its
quite impossible and thus we
decided to obtain the distance in tacheometry.
)6( !ll readings were recorded in a table provided.
))( Then the error of traverse was determined by calculating the
total internal angle andcompares it to the theoretical value.
TACHEOMETRY
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)( *e did the tacheometry using the same location and the same
e&act traverse station.
+( ! tripod was placed above the first point and a plumb line,
'a piece of lead with a
tapering end hung to the base of the tripod pointing e&actly
on the nail hanging by a thin
thread(, plumb bob was placed at the point of convergence of the
legs of the tripod, and
made to drop freely onto the top of the nail.
( To set up the theodolite properly we refer to the bubble
ad3ustment method.( 4ame procedures are repeated to set up the
theodolite at each station.
/( In tacheometry we faced several problems such as difficulties
in obtaining e&act 567 for
the vertical angles. This is due to the environmental
condition.
0( Then we obtain the reading of the stadia hair 'upper and
lower(, mid-reading, hori%ontal
and vertical angle from each station.
1( 8ach data was tabulated in the table given.2( The error
internal angle were determined.
DISCUSSION
LEVELLING
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Levelling is operation the comparison of heights of point on the
surface of the
earth. In levelling, the things that we have to measure is the
backsight and the foresight.
*e have start the levelling from the ukit !yer until reached the
mosque. It is about
.2)1 km. Then we continue from mosque until ukit !yer back. 4o
the total distance is
double. In levelling there are two methods of calculating level.
The first one is
collimation method and the second one is 9ise-and-:all method.
;ur group have choose
9ise-and-:all method to calculate the level. *e have measure the
backsight and the
foresight. Then, we have to take backsight minus foresight. If
the answer is positive, it
known as rise but if the answer is negative, it known as
fall.
*e have to calculate all the backsight and foresight. ased on
the result that we
have calculated for the levelling, finally we get the level
which is 555.21.It is only 6.)+0
to )666 km. It is because due to the error that may occurred
during carry this e&periment.
The error may occurred when taking the measurement due to
paralla& error. To prevent
this error, we have to take the repeated readings and fine the
average. Then, when holding
the stuff, the bubble of the stuff may not be in the middle of
the circle. This make the
stuff do not vertically straight. To prevent this error, we have
to make sure that the bubble
is in the middle of the circle. esides that, the autolevel also
have the bubble to show the
stability and accuracy. *e have to make sure that, the bubble at
the autolevel also is in
the middle of the circle. This is because, along the road, the
surface of the road is not
plane. There is up and down in road. :urthermore, using the
9ise-and-:all method, it is
laborious and several calculations. This system is suitable for
fly leveling where they are
no intermediate sights. In
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Tacheometry is a branch of surveying in which hori%ontal and
vertical distances
are determined by taking angular observations with an instrument
known as tacheometer.
This method is very useful to us since the environmental
conditions in our assigned
location aren=t very suitable for direct surveying like
traverse. :irstly we take a look
around the ma3or location described by the lecturers and choose
the appropriate point so
that there are no difficulties while tacheometry is done. The
point must be seen clearly
from consecutive point and any minor obstacles that can be
removed are removed. In this
practical the readings that must be considered are the
hori%ontal and vertical angle, the
stadia readings 'upper and lower(, and also the mid-reading.
:rom the theoretical formula
that we learnt in class, the value of > 'the hori%ontal
distances(, and ? 'vertical
distances(, and also the height of instrument at each
station.
*e didn=t manage to obtain e&act 56@ since there are so many
obstacles such as
trees and other structure. Therefore the vertical must be taken.
*e divided the area of
surveying into two ma3or areas. The first area covers half of
the location but not including
the poolside. The difference sign in the vertical distances
obtained is due to the
difference level of each point considering the elevation and
depression angle 'the sight
uphill and sight downhill(. *ith this value we can determine the
reduced level at each
point precisely. Then we sketch the plan accordingly to its
ratio and importance structures
are included to give a better graphical appearance. The actual
si%e might not be e&act to
its original structure since it is the bird view. !ll the ma3or
station determined by the
lecturers has taken into consideration an include in our plan.
The errors occurs in this
practical might due to the environmental factor and also the
paralla& error done while
taking the stadia reading. The surface condition of the location
such as big drain, river,
pool, and big rock preventing us from getting a straight view
also made us choosing more
point and thus increasing the number of errors.
TRAVERSE
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:or this e&periment, we have conducted a traversing with a
theodolite in >utan
Lipur ukit !yer. !s we know traversing is a series of survey
points whose relative
positions are determine by measured distance and direction
between each consecutive
point. In this survey , we have separate the area to two area
due to the area is too big and
there are too many things such as the branches of trees and the
leaves or the utility of the
park that block our sight while the survey is done when we want
determine our hori%ontal
.The both area of our survey consist of four corners and it is
combine through a line of
each area, therefore by using the formula )26'n-+(, we can find
the total interior angle is
06 degree. In this survey we have also can determine the
distance of the points but due
to the distance of each points is far from each other, we
calculate the distance using
formula. :rom this survey, we can determine the location and
distance of each item in the
park. In our survey, we are doing closed traverse which starts
and ends on the point of
known position. Then our survey is also a loop traverse because
it starts and ends at the
same point. y the result we get in the survey, we can calculate
the latitude and departure
and the ad3usted coordinates of the survey we do.
*hen we are conducting the survey, several errors might occur
.;ne of the error
that occur during the survey is conducted is systematic error,
where it is due to the
sensitivity of the theodolite. esides that, paralla& error
also might occur while
conducting the survey as they didn=t observed the result while
taping is not watch 56
degree. Therefore we need to calculate the linear error of
misclosure, 8 using the formula
'latABdepA( and the precision error using the formula
8"'perimeter(. y calculating
these values, we will know whether our result is precise or
not.
CONCLUSION
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:rom the three e&periments that we have done, we are now
have gained a lot of knowledge of
basic geomatic work and how to conduct the instruments.
In levelling, we are now completely understood on how to do the
work. Long distance and
working under the heat of the sun have really gives us
e&periences. :rom what we have done, we
successfully obtained a good result of the e&periment.
In tacheometry and traverse, we have done both in one
measurement. It means that everytime we
take the measurement, we will use the value for both tacheometry
and traverse calculations. The
whole area is like a trape%ium shape. :or such a huge area, we
divided it into two portions. *e
calculate the distance using formula. *e get the degree of
stations in clockwise direction. This
kind of surveying works also have give us a lot of
e&periences. *e have mastered on how to
handle the instruments such as theodolite, staff, tape, and
tripod.
!s a conclusion, we finally have reach the real ob3ectives of
the e&periments. 8&periences and
knowledge of how to do the real leveling, techeometry, and
traverse are the most important part
of this Deomatic Camp and honestly, we were having a good time
doing it.
REFERENCES
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Doogle.com
E4urveying for Construction=, *illiam >yslop Irvine
EConstruction 4urveying and LayoutF ! 4tep-y-4tep :ield
8ngineering
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Practical 7geomatic camp
