INTRODUCTION
Advanced
instruments plays very vital role in investigating their basic technical
parameters to improve the engineering, surveying measurements Total station is
a combination of an electronic theodolite and electronic distance meter makes
it possible to determine the coordinates of a reflector by aligning the
instrument cross hair on the reflector and simultaneously measuring the
vertical and horizontal angles and slope distance a micro processor in the
instrument takes care of recording reading, and the necessary computations. The
data is easily transferred to a computer where it can be used to generate a
map. The GPS concept is based on time. The satellites carry very stable atomic
clocks that are synchronized to each other and ground clocks. GPS satellites
continuously transmit their current time and position. GPS provides specially
coded satellite signals that can be processed in a GPS receiver, enabling the
receiver to compute position, velocity and time. GIS is more than a tool for map
preparation or for generating presentation graphics that allows a user to bring
together spatial data and databases containing attribute and other types of
data (e.g., images or graphs). This provides users the opportunity to realize
greater benefits from their data because most data include a significant
geographic component. Aerial survey is recognized for aero photogrammetry, part
of photogrammetry using aero planes, helicopters, UAVs, balloons or other
aerial methods, where the camera is placed in the air. Drones are very popular
in travelling sectors as mass media networks patronize its functionality and
efficiency when capturing videos and images. Measurements on aerial images are
provided by photogrammetric technologies and methods. In the present study,
Surveying of total Shraddha Park college, Nagpur campus was done to check the
accuracy of these advanced instruments and to determine most accurate
positioning of college campus as well as developing the map using the surveying
coordinates in Auto Cad Software. The decisions based on essential
characteristics of engineering that are accuracy in measurement, actual
positioning, and economy.
DEFINITION OF SURVEYING
In
general, surveying is performed to determine the relative location or
positioning of points on or near the earth's surface. More specifically,
surveying is the science of making measurements, relative to known or assumed
datum’s and standards, and applying the principles of mathematics to such
measurements to determine existing or future horizontal and vertical position,
from area, magnitude, boundaries, and extent of land parcels and topographical
features.
Surveying
encompasses the following categories:
1.
Geodetic Surveys - Surveys, which establish control networks on a mathematical
datum so that measurements will reflect the curved (ellipsoidal) shape of the
earth.
2.
Land Surveys - Surveys which include retracement of existing land ownership
boundaries or the creation of new boundaries.
3.
Engineering Surveys - Surveys performed for the location, design, construction,
maintenance and operation of engineering projects.
4. Construction Surveys - Surveys which
establish stakes in the ground, and other like reference points, at known
horizontal and vertical positions to define location and size of each component
of the facility to be constructed, enable inspection of contract items, and
serve as a basis of payment for work.
5.
Cartographic Surveys - Map making from original surveys.
IMPORTANCE OF SURVEYING
1.
The Basic Engineering Discipline - Surveying is basic to all civil engineering
works. In transportation engineering, surveying provides the foundation and
continuity for route location, design, land acquisition, and all other
preliminary engineering. Surveys also set a basic "framework" of
stakes, which is used by contractors and engineers in building and inspecting
transportation projects.
2.
The Thread of Continuity - Surveying is the single engineering function which
links all the phases of a project including conception, planning design, land
acquisition, construction and final monumentation.
3.
Basis for Efficiency - To a great degree, the acceptability and
cost-effectiveness of planning, land acquisition, design, and construction are
dependent upon properly performed surveys.
1]
STUDY
OF THEODOLITE
·
Objective: To study different parts of Theodolite and temporary adjustments.
·
Equipment: Theodolite.
SKETCH:
Figure 1: Transit
theodolite (optical theodolite)
VERTICAL AXIS: It is
the axis about which the telescope can be rotated in a horizontal plane.
HORIZONTAL AXIS: It is
the axis about which the telescope can be rotated in a vertical plane.
LINE OF COLLINATION: It
is the imaginary line joining the intersection of the cross hairs of the
diaphragm to the optical center of the object glass and its continuation.
AXIS OF THE TELESCOPE:
It is the line joining the optical center of the object glass to the center of
the eye-piece.
AXIS OF THE LEVEL TUBE:
It is the straight line tangential to the longitudinal curve of the level tube
at the center of the tube.
CENTERING: The process
of setting the theodolite exactly over the station mark.
·
Equipment Description:
TELESCOPE: It consists
of eye-piece, object glass and focusing screw and it is used to sight the
object.
VERTICAL CIRCLE: It is
used to measure vertical angles.
LEVELLING HEAD: It
consists of two parallel triangular plates called tribrach plates. Its uses
are:
1) To support the main
part of the instrument,
2) To attach the
theodolite to the tripod.
LOWER PLATE: It
consists of lower clamp screw and tangent screw.
UPPER PLATE: The upper
plate is attached to the inner axis and it carries two verniers. It consists of
an upper clamp screw and tangent screws. These screws are used to fix upper
plate with lower plate accurately.
FOOT SCREWS: These are used to level the
instrument.
PLUMB BOB: It is used
to center theodolite exactly over the ground station mark.
SWINGING THE TELESCOPE: It means turning the
telescope about its vertical axis in the horizontal plane. A swing is called
right or left according as the telescope is rotated clockwise or counter
clockwise.
FACE LEFT: If face of
the vertical circle is to the left side of the observer, then the observation
of the angles taken is known as face left observation.
FACE RIGHT: If the face
of the vertical circle is to the right side of the observation, then the
observation of the angles taken is known as face right observation.
CHANGING FACE: It is an
operation of bringing the face of the telescope from left to right and
vice-versa.
2] STUDY OF TOTAL STATION
·
Objective: study of total station
·
Equipments: Total station (Leica TS02 Total Station)
SKETCH:
· Instrument
Setup Procedure (Leica TS02 Total Station):
TRIPOD:
1.
Set up the tripod at the appropriate height.
2.
Visually check that the tripod is level and centered over the ground point.
3.
Press the tripod legs into the ground to guarantee a firm foothold.
4.
Attach the instrument to the tripod and “center” the foot screws.
PLUMB:
5.
Turn on the instrument. The laser plummet will be activated automatically, and
the Level/Plummet screen appears. If this screen does not appear, press user
key 1.
6.
IF NECESSARY Move the position of the tripod legs to make large adjustments to
center the plummet over the ground point.
7.
Use the foot screws to make small adjustments to center the plummet over the
ground point.
ROUGH LEVELING:
8.
Adjust the height of the tripod legs to level the circular level bubble. Note:
Do not move the legs from their position just lengthen or shorten them, one at
a time, as necessary to bring the bubble into center.
FINE PLUMB & LEVEL:
9.
At this time your instrument should be very close to level and very close to
the ground point, check the plummet & circular level bubble to verify this.
If this is not the case you must repeat the Plumb & Rough Leveling steps
above, otherwise, continue on to the next step.
10.
Turn the instrument until it is parallel to two footscrews.
11.
Center the electronic level of the first axis by turning the two footscrews.
Arrows show the direction of rotation required. When the electronic level is
centered the arrows are replaced by checkmarks.
12.
Center the electronic level for the second axis by turning the last footscrew.
An arrow shows the direction of rotation required. When the electronic level is
centered the arrow is replaced by a checkmark.
13.
When the electronic level is centered and three checkmarks are shown, the
instrument has been perfectly leveled up.
14.
IF REQUIRED, Center the instrument precisely over the ground point. Loosen the
instrument from the tripod (loosen only) and slide the instrument over the
point while sighting.
3] SURVEY OF AN AREA BY CHAIN SURVEY (CLOSED
TRAVERSE)
· Objective:
To
survey an open field by chain survey in order to calculate the area of the open
field.
· Equipments:
Chain,
Tape, Ranging Rods, Arrows, Cross Staff.
SKETCH:
· Procedure for
surveying the given open field (Closed Traverse):
Note: This procedure is
general procedure only. This procedure varies with the experiment given to
students. Therefore students are required to write the procedure according to
the experiment given to them.
Example:
1. ABCDEF is the
required closed traverse open field to be surveyed for calculating the area as
shown in Fig
2. From the station A
the length of all the opposite corners such as AC, AD and AE are measured with
a chain and the longest distance is considered for laying off the main chain
line. In this case AD is the longest and a chain line running from A to D is
laid.
3. Offsets to corner
points B, C, E and F are now laid from the chain line AD either by tape or
cross-staff and their foot of offsets are G, I, J, H respectively.
4. All the offset
lengths GB, HF, IC and JE are measured either by chain or tape depending on the
length of offsets.
5. The distances
between all the points AG, GH, HI, IJ and JD are also measured along the chain
line.
6. Area Calculations:
(Note: Areas of all triangles and trapeziums are calculated and added together
to calculate the total area of open field (Closed Traverse) as described in
class).
FORMULA:
Area of the triangle Δ = √ s (s-a) (s-b) (s-c)
Where S = (a + b+ c) / 2
a, b, c, are the sides of the triangle.
4] CHAINING ACROSS OBSTACLES
· Objective:
To survey an area by
chain survey across obstacles and to calculate the obstructed lengths by using
different methods.
· Equipments: Chain, Tape, Ranging Rods, Arrows, Cross Staff.
SKETCH:
· Obstacles to
Chaining:
During measurements, it
is impossible to set out all the chain lines in a straightforward method
because of a variety of obstacles to chaining and ranging in the field.
1) Obstacles to
measurement: The obstacles which do not obstruct the ranging (view) like ponds,
rivers are known as Obstacles to Measurement.
2) Obstacles to
alignment: The obstacles which we cannot see across, i.e. both the chaining and
ranging are obstructed, e.g. houses, stacks, etc. are known as Obstacles to Alignment.
·
Procedures to find out Obstructed Length:
1) Obstacles to
measurement:
A) First Method:
Let ABCD be a chain line obstructed by a pond
(Fig 1). Let BC be the obstructed length. Two offsets BE and CF of equal
lengths are made at B and C and chaining is done along EF to measure the
distance EF.
Now the required
obstructed length BC is equal to the measured distance EF.
Therefore, BC = EF
B) Second Method:
Let AB be the
obstructed length across the river AC is laid off, of any convenient length,
perpendicular to the required distance AB.
Now a perpendicular is
laid off from C such that it meets the extended line of AB at D.
Triangles ABC and ADC
are similar triangles.
From the principle of
similar triangles,
AB / AC = AC / AD
Therefore, obstructed
length AB = AC2 / AD
C) Third Method:
Let AB be a chain line
obstructed by a river (Fig 3). A point I is assumed anywhere in line with the
required distance AB. A point H is taken in such a way that HJ = HI and HK =
HB.
Now a point L is
established in line AH and at the same time in the line JK produced.
Triangles KHL and ABH
are similar triangles and their corresponding sides are equal to each other as
the points K, B and I, J are equidistant either side from H.
Therefore, the
obstructed length AB = KL
5] STUDY OF LEVEL AND LEVELLING STAFF
· Objective:
Study of components of
dumpy level and leveling staff.
·
Equipments:
Level, Leveling staff,
Tripod, Staff bubble.
1.
Levels A level
is basically a telescope attached to an accurate leveling device, set upon a
tripod so that it can rotate horizontally through 360°. The following figure
shows the level and its components.
Figure 1: Level
2. Tripod The tripod
consists of three legs and a head where the level instrument is mounted. The
tripod could be of aluminum or wood material. When leveling the level
instrument, the tripod head must be set approximately level beforehand by
adjusting the tripod legs.
3. Leveling staff The
leveling staff is a box section of aluminum or wood, which will extend to 3 or
5 m in height by telescoping, hinging or addition of sections. One face has a
graduated scale attached for reading with the cross-hairs of the level
telescope.
4. Staff bubbles These
are generally a small circular bubble on an angle plate which is held against
one corner of the staff to ensure that the staff is held in a vertical
position. If the staff is not held vertical, the reading will be too large and
may be significantly in error.
SETTING UP OF THE DUMPY LEVEL:
1. Release the clamp
screw of the instrument
2. Hold the instrument
in the right hand and fix it on the tripod by turning round only the lower part
with the left hand.
3. Screw the instrument
firmly and bring all the foot screws to the center of its run.
4. Spread the tripod
legs well apart and fix any two legs firmly into the ground by pressing them
with the hand.
5. Move the third leg
to up or down until the main bubble is approximately in the center.
6. Then move the third
leg in or out until the bubbles of the cross-level is approximately in the
center.
7. Fix the third leg
firmly when the bubbles are approximately in the centers of their run.
LEVELLING UP:
1. Place the telescope
parallel to a pair of foot screws.
2. Bring the bubble to
the center of its run by turning the foot screws equally either both inwards
and both outwards.
3. Turn the telescope
through 90º, so that it lies over the third foot screw.
4. Turn this third foot
screw so that the bubble comes to the center of its run.
5. Turn the telescope
through and check whether the bubble remains central.
ELIMINATION OF PARALLAX:
1. Remove the lid from
the object glass.
2. Hold a sheet of
white paper in front of the object glass.
3. Move the eyepiece
right or left until the cross hairs are distinctly visible.
4. Direct the telescope
towards the staff.
5. Turn the focusing
screw until a clear and sharp image is formed in the plane of the cross hairs.
Conclusion
we know how to determine the
final bearing by using suitable method. Then, we have a knowledge of all the
equipment required to carry out. And then, we know the advantages of bearing
and their use in various survey works.
After done the practical, we understand how to
understand and describe closed traverse survey. Example of tool station,
tripod, prism, prismatic
We are to be familiar with the checks and errors in a
closed travers and solve them. We are also to be familiar with various
types and methods of traverse surveying for detailing and we are know well
about the traverse computation and be fluent in it. We also be able to read
After that, we also be able carry out and reduce a closed traverse. And
then,
we get the basic principles of traversing and experiences of the
field works procedure, so that we are able to establish the control points by
surveying approach with minimize errors and practicable. Furthermore, we
obtained develop skill in using total station thus could be explored more
function that assist on the instrument. Finally, we get to know or understand
collimation error and how it can be corrected
REFERANCES
WWW.Surveyingmanual.com
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