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1. TACHEOMETRY SURVEY
OBJECTIVES:-
 Producethe topographic map and detailed plan of the proposed area by using surveying
software(Theodolite, Total Station)
INSTRUMENT REQUIRED:-
 Total Station or Theodolite
 Stadia Rod
 Peg
 Reflected Prism (i.e. only fortotal station)
 Tripod Stand
INTRODUCTION:-
Tacheometry survey is a branch of surveying in which horizontal and verticaldistance of points
are obtained by optical measurement avoiding ordinary and slower process of measurement
tape. Tacheometric surveys are usually performed to produce contourand details plans for
further work,or to produce coordinates forarea and volume calculations. Observation are
usually performed fromknown survey stations, oftenestablished by traversing.
THEORY:-
Useda Total Station,ableto readdistanceby reflectingoffaprism.
It is now possible to produce plans of large areas that previously wouldhave taken weeks, in a
matter of days. This instrumentation has facilitated the development of this method of detail
and contoursurveying into a very slick operation.
Useda Theodolite,ableto readdistanceby sightingfrominstrumentat Stadiarods.
It is also possible now to detailing but it is slowest process than Total Station.
FIELDWORKS FORTRAVERSING:-
a. Reconnaissance:Itis done to-
 To locatesuitable positions for stations, poorly executed reconnaissance can result from
difficultiesat later stages leading waste of time and inaccurate work
 To obtain overall picture of the area.
b. Duringselectionof stationfollowingpointsshouldbenoted
 Number of station should be kept minimum as possible
 Length of traverse legs should be kept as long as possible to minimize effectof centering
error, however toolong leg can also result from refractionerror,
 Station should be located such that they are clearly intervisible
 Station should be placed on firm, level ground so that the theodolite/total station and
tripod are supported adequately during measurement
 Interior angle of the station between traverse legs should not be less than 30° or should
not be around 180° to minimize error during plotting

2. c. Stationmarking
 Station marking needs to be done by the permanent marker foreasy allocationof station
throughout the survey period.
 Generally for traverse purpose, wooden pegs are flush into the ground, a nail is tapped
into the top of peg to define exact position of station
 A reference or witnessing sketch of the features surrounding each station should be
prepared especially if the stations are to be leftfor any time beforeused or if they are
required again
d. Linearmeasurementof traverse line will normally be measured by EDMor by
measuring tape
 During Linear measurement, for precision both way (forwardand backward direction)
measurement is carried out and discrepancy should be better than 1:2000
e. ForAngularmeasurement,if the internal angles are being read, it is usual to proceed
from station to station round the traverse in an anticlockwisedirection
 Generally, more than one set of reading is preferred for higher accuracy measurement
along withboth face (right and left face) reading
 If external angles are observed then one should occupy the stations in a clockwise
direction
 When all internal angles are measured, sum of internal angle should be equal to (2n-
4)*90, for external angle (2n+4)*90,
REQUIREMENTS OF FIELD NOTES:-
 Accuracy:Field data and reference data should be accurately noted
 Integrity:A single omitted measurement or detail can nullify the use of notes for
plotting. So Notes should be checked carefully forcompleteness before leaving
 Legibility:Notescan be used only if they are legible. A professional-looking set of notes
is likely to be professional in quality
 Arrangement:Note forms appropriate to the particular survey contribute to accuracy,
integrity, and legibility
 Clarity:Advanceplanning and proper field procedures are necessary to ensure clarity of
sketches and tabulations and to minimize the possibility of mistakes and omission.
CONCLUSION:-
We know that when the stations have been sighted, a sketchof the traverse should be prepared
approximately to scale. The stations are given reference letters or numbers. This greatly assists
in planning and checkingof field work.
RESULT:-
Making topographic map and detailed plan of proposed area.