Survey Report Written for Tacheometry.

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Setting Trends in Higher Education, Research and Innovation
School of Civil Engineering and Geospatial Engineering
Bachelor of Geomatics Engineering and Geospatial Systems
Bachelor of Geospatial Information Science
INTERNAL ATTACHMENT
Group 4
Fieldwork 3 Report
TACHEOMETRY
Student Name Registration Nº
Gavin Kendo ENC221-0330/2016
Stildon Kimani ENC222-0337/2016
Tarri Halakhe ENC221-0159/2016
Calvin Kiplimo ENC222-0168/2016
Ivy Njeri ENC221-0157/2016
Raymond Rawlings ENC222-0362/2016
Sharon Mwanza ENC221-0098/2016
Barasa Samuel ENC222-0351/2016
Faith Mwende ENC221-0311/2016
Kosgei Antoney ENC222-0354/2016
Paul Akelo ENC222-0331/2016

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Introduction
Tacheometric survey (Tacheometry) is a branch of surveying in
which horizontal and vertical distance of points are obtained by
optical measurement avoiding ordinary and slower process of
measurement tape. Tacheometric surveys are usually performed to
produce contour and details plans for further work, or to produce
coordinates for area and volume calculations. Observation are
usually performed from known survey stations, often established by
traversing.
Objectives:
 Produce the topographic and detail plan of the proposed area
using surveying software.
 To provides a check on distances measured with the tape.
 To Checking of already measured distances.
Instruments to be used:
1. Theodolite.
2. Staff.
3. Tripod.
4. Ranging Rod.
Procedure
Tacheometry or detail survey is a continuation of traversing and
leveling wherein all the detail are observe from the traverse point
with (x, y, h).
 All the traverse point had the reduced level from the
leveling.
 The leveling data of traverse point is referred.
1) All the details including topography and man-made features have
observed.

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2) The instrument was setup over the traverse (i.e. station 4). The
pole with mini prism was put at the back sight (station 1) and
foresight (station 3).
3) The temporary adjustment (leveling, centering) over the point was
performed.
4) The height of instrument (IH) was measured and recorded.
5) The bearing for line 4-1 was set as datum. The distance of station
4-station 1 was measured and recorded. Used a final bearing
from traverse sheet.
6) A pole was used as a target over the point. The pole height (HT) is
measured and the reading was recorded.
7) The horizontal bearing (HR), horizontal distance (HD) and vertical
distance@height difference (VD) for each observation was
recorded.
8) All the features surrounding the station 4 were observed. We
make sure the HT was measured and recorded for each
observation.
9) The instrument was moved to the next station (i.e. station 2). The
bearing for line 2-3 was set as a datum. The process was
repeated and all the features from station 2 were observed. The
IH at each station setup was measured.
10) Additional control point must be setup when it found missing
or disturbed; or obstruction of the features from observed
station.
Sources of Error
 They are staff readings and tilt of the pole or staff. Observer
tends to make wrong observation when observing the staff
reading, they might misread the staff marking scales and this
brought to the crucial error along the booking process.
Besides, the tilting of the staff rod can influence the accuracy
of the height readings taken from the staff. When the staff is
not truly vertical (90º) or almost to it, the reading taken is
incorrect and lead to the failure of tachometry process.
 Errors in conducting tachometry survey also caused by
natural causes. These include errors due to high winds.

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During high winds, it is difficult to keep the staff vertical and
read it accurately. Works should be undertaken during hot
mid-day period. In very hot conditions, the instrument should
be protected with an umbrella to avoid errors due to the
unequal expansion of different parts of instruments. Work
may also be hampered by bad visibility due to strong sunlight
and glare.
 Error due to manipulation and sighting are inaccurate leveling
of the instrument, inaccurate reading of horizontal line and
vertical angles, poor focusing errors, inaccurate bisection of
the target, inaccurate reading of the staff intercept and lastly
due to errors in holding the staff.
 Instrumental errors. They are those caused by the adjustment
of the instruments used or faults in them. Any errors in these
measurements have serious implications in the heights and
distances measured with the instruments. To avoid such
errors, the following points should be taken care of:
a) The tachometer should be in perfect adjustment for
taking observation.
b) The altitude bubble should be at the centre of its run
while reading the vertical circle for angles. Any index
error should be detected and eliminated or accounted for.
c) The multiplying and additive constants of the instrument
should be periodically checked to see that they indeed
have the values that are being used.
d) The stadia rod (staff) should be accurately divided into
parts. The graduations should be uniform and free of
errors. They should be marked bold for greater visibility
from a large distance.
Conclusion
In conclusion, after complete this project we can know the
object detail in our area. Then we use trimmap software to analyze
our data and we can know the result. To avoid errors, we must be

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carefully when using the theodolite and careful when taking the
readings.
Lastly, after we get contour, we know the height of the ground
and its datum. In engineering field, we use contour to determine the
ground level is suitable for construction work or not.