TOTAL STATIONA total station or TST (total station theodolite) is an electronic/optical instrument used in modern surveying and building construction. The total station is an electronic theodolite (transit) integrated with an electronic distance meter (EDM) to read slope distances from the instrument to a particular point.Robotic total stations allow the operator to control the instrument from a distance via remote control. This eliminates the need for an assistant staff member as the operator holds the reflector and controls the total station from the observed point.

Angle measurement

Most modern total station instruments measure angles by means of electro-optical scanning of extremely precise digital bar-codes etched on rotating glass cylinders or discs within the instrument. The best quality total stations are capable of measuring angles to 0.5 arc-second. Inexpensive "construction grade" total stations can generally measure angles to 5 or 10 arc-seconds.

Distance measurement

Measurement of distance is accomplished with a modulated infrared carrier signal, generated by a small solid-state emitter within the instrument's optical path, and reflected by a prism reflector or the object under survey. The modulation pattern in the returning signal is read and interpreted by the computer in the total station. The distance is determined by emitting and receiving multiple frequencies, and determining the integer number of wavelengths to the target for each frequency. Most total stations use purpose-built glass corner cube prism reflectors for the EDM signal. A typical total station can measure distances with an accuracy of about 1.5 millimeters (0.0049 ft) + 2 parts per million over a distance of up to 1,500 meters (4,900 ft).Reflectorless total stations can measure distances to any object that is reasonably light in color, up to a few hundred meters.

Coordinate measurement

The coordinates of an unknown point relative to a known coordinate can be determined using the total station as long as a direct line of sight can be established between the two points. Angles and distances are measured from the total station to points under survey, and the coordinates (X, Y, and Z or easting, northing and elevation) of surveyed points relative to the total station position are calculated using trigonometry and triangulation. To determine an absolute location a Total Station requires line of sight observations and must be set up over a known point or with line of sight to 2 or more points with known location.For this reason, some total stations also have a Global Navigation Satellite System receiver and do not require a direct line of sight to determine coordinates. However, GNSS measurements may require longer occupation periods and offer relatively poor accuracy in the vertical axis.

Data processing

Some models include internal electronic data storage to record distance, horizontal angle, and vertical angle measured, while other models are equipped to write these measurements to an external data collector, such as a hand-held computer.When data is downloaded from a total station onto a computer, application software can be used to compute results and generate a map of the surveyed area. The newest generation of total stations can also show the map on the touch-screen of the instrument immediately after measuring the points.

Applications

Total stations are mainly used by land surveyors and civil engineers, either to record features as in topographic surveying or to set out features (such as roads, houses or boundaries). They are also used by archaeologists to record excavations and by police, crime scene investigators, private accident reconstructionists and insurance companies to take measurements of scenes. Meteorologists also use total stations to track weather balloons for determining upper-level winds.

Mining

Total stations are the primary survey instrument used in mining surveying.A total station is used to record the absolute location of the tunnel walls (stopes), ceilings (backs), and floors as the drifts of an underground mine are driven. The recorded data are then downloaded into a CAD program, and compared to the designed layout of the tunnel.The survey party installs control stations at regular intervals. These are small steel plugs installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed in opposite walls, forming a line perpendicular to the drift. For back stations, two plugs are installed in the back, forming a line parallel to the drift.A set of plugs can be used to locate the total station set up in a drift or tunnel by processing measurements to the plugs by intersection and resection.

Mechanical and Electrical Construction

Total stations have become the highest standard for most forms of construction layout.It is most often used in the X and Y axis to layout the locations of penetrations out of the underground utilities into the foundation, between floors of a structure, as well as roofing penetrations.Because more commercial and industrial construction jobs have become centered around Building Information Modeling (BIM) the coordinates for virtually every pipe, conduit, duct and hanger support are available with digital precision. The application of communicating a virtual model to a tangible construction potentially eliminates labor costs related to moving poorly measured systems, as well as time spent laying out these systems in the midst of a full blown construction job in progress.

OBJECTIVESTo introduce and familiarize students with measuring distance and angles with a total station.

TERMS IN TOTAL STATION

Level Line

A line lying on the level surface is known as a level line. Every point of a level line is equidistant from then centre of the earth. The cross section of still water of a lake represents a level line .

Reduced Level ( RL )

It is a vertical height or depth of a point above or below the datum. It is also known as elevation of the point. The elevation of a point is positive or negative according as the point lies above or below the datum

Bench Mark ( BM )

A benchmark is a point of reference which is convenient for leveling in a given locality. The relation to sea-level is very precise and obtained by running a level circuit such that the elevation of the beginning and the end of the circuit are known and tied together .

Temporary Bench Mark ( TBM )

Temporary benchmark is fixed dots but behave less permanent and established nearby to site survey to save works reference to benchmark which may too long

Backsight (B.S) or Backsight Reading

It is a staff reading taken on a point of known elevation (or reduced level) as on a bench mark or a change point. It is the first staff reading taken after the level is set up and levelled. It is also called a plus sight.

Intermediate Sight (I.S) or Intermediate Sight Reading

It is any other staff reading taken on a point of unknown elevation (or reduced level) from the same set up of the level. All sight taken between the back sight and fore sight are intermediate sights.

Fore Sight (F.S) or Fore Sight Reading

It is a staff reading taken on a point whose elevation (or reduced level) is to be determined as on a change point. It is the last staff reading taken before shifting of the level to another position. It is also called a minus sight.

Change Point

The point at which both the fore sight and back sight are taken during the operation of leveling, is called a change point. Two sight, are taken from two different instrument stations, a fore sight to ascertain the elevation of the point while a back sight is taken on the same point to establish the height of the instrument of the new setting of the level. The change point is always selected on a relatively permanent point .

Aras Lompat

Kerja pengukuran aras untuk menyemak satu siri pengukuran yang telah dijalankan dari titik akhir ke titik mula

EQUIPTMENTSEQUIPTMENTS FUNCTIONS

AUTOMATIC LEVELS In automatic level, spirit level tube is not used anymore for horizontal collimation set up.But, adjustment still need to make sure that circular bubble is exactly in the centre of circle.This level are easy to set up and used

DIGITAL LEVELS This instrument has been designed to carry out all reading and data processing automatically via an on-board computer which is accessed through a display and keyboard. Used with a special bar-coded staff There is no need to read the staff as the display will show the staff reading about two or three seconds after the measuring key has been pressed.In good condition, a digital level has range of about 100m.Observations are taken quickly over longer distances without the need to read staff or record anything by hand. The data stored in a digital level can also be transferred to a removable memory card and then to a computer

TRIPOD The legs of the tripod are adjustable and are made of wood, fiberglass or aluminum and are adjustable for use with many different pieces of surveying equipment. Tripods made of wood or aluminum can influence readings in certain weather conditions, fiberglass can be heavy to carry when surveying over various terrains and distances. Tripods come with two different styles of heads: flat or dome. Dome heads allow for more adjustment suitable for automatic level. While flat head tripods have less play suitable for dumpy and Titling levels, but are sometimes easier to fit.

PEGS

STAFF Is the equivalent of a long ruler and it enables distances to be measured vertically from the

horizontal plane established by a level to points where heights are required.

STAFF BUBBLE The rectangular sectioned rods are either the folding (hinged) or the sliding variety. Newer fiberglass rods have oval or circular cross section and fit telescopically together for heights of 3, 5 and 7 m. Benchmark leveling utilizes folding (one-piece) rods or invar rods, both of which have built-in-handles and rod levels. When the bubble is centered, the rod is plumb. All other rods can plumbed by using rod level

MEASURING TAPE Used to measure the vertical distance between two points. Only applicable when an unobstructed vertical line between the two points exists.

FIELD WORK BOOK Field book used to record reading and make barrel level count. Recording and count can be made with two methodologies, namely rise and fall method or height Collimation

ELECTRONIC MEASUREMENT DISTANCE

The electromagnetic principles of EDM theory and operation are well covered in most surveying text books and on the internet. The intent here is to give the reader a general understanding of EDM so that error sources are better understood and controlled.

PRISM Transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a

triangular base and rectangular sides, and in colloquial use "prism" usually refers to this type. Some types of optical prism are not in fact in the shape of geometric prisms. Prisms can be made from any material that is transparent to the wavelengths for which they are designed. Typical materials include glass, plastic and fluorite.

PRACTICAL THEORYElectromagnetic Energy

The electromagnetic principles of EDM theory and operation are well covered in most surveying text books and on the internet. The intent here is to give the reader a general understanding of EDM so that error sources are better understood and controlled.An EDM uses electromagnetic (EM) energy to determine the length of a line. The energy originates at an instrument at one end of a line and is transmitted to a "reflector" at the other end from where it is returned to the originating instrument. The nature of the "reflector" is dependant on the type of EM. If electro-optical (infrared or laser) EM is used then the "reflector" is typically a passive medium which bounces the signal back. If the EM is microwave, then the reflector is a second instrument which captures the incoming energy and re-transits it back to the originating instrument.

Electro-optical System

Microwave System

In either case the measurement is the total distance from the instrument to the reflector and back to the instrument. Comparing the two EM types:

EM Type Advantages Disadvantages

Electro-optical Less susceptible to atmospheric conditions.

Less expensive: only a single transmitter needed.

Shorter range.

Microwave Can penetrate fog and rain.Longer range.

Atmospheric affects are greater.

Transmitter at both ends allows voice communication.

Susceptible to ground reflected signals.More expensive: requires two transmitters.

The rest of this chapter will limit discussion to electro-optical EM instruments since the majority of EDMs (and Total Stations) employ that EM type.

Distance Determination

An EDM does not determine distance by measuring the travel time of the EM signal. Instead, an EDM uses the signal structure and determines the phase shift. The EM signal has a sinusoidal wave form. Remember from trigonometry that the sine curve looks like:

Sine Curve

This wave form repeats every 360°. The distance between wave form ends is the wavelength, ?:

Wavelength

Different wavelengths are generated at different modulation frequencies, f. Wavelength, frequency, and the speed of light are related by:

Eqn (III-1)

The wavelength is a known quantity since it is generated by the EDM at a specific frequency. The signal leaves the EDM at 0° phase, goes thru N number of full phases on its way to

and from the reflector, and returns to the EDM at some angle between 0° and 360° creating a partial wavelength, p:

Signal Propagation

The total distance is (Nλ + p). The EDM can very accurately determine the length of the last partial wavelength from its phase.

Example

Assume the wavelength in Fig 5 is 20.00 ft. The last partial wave is:

If N=10, then the total distance EDM-reflector-EDM is:

The distance between the EDM and reflector is half that: 204.584 ft / 2 = 102.292 ft.

Unfortunately, the EDM can't determine it how many full wavelengths occurred along the distance.So how does it resolve this dilemma? By decreasing the frequency by a factor of 10 and repeating the process. Decreasing the frequency by a factor of 10 increases the wavelength by a like amount. The partial wavelength at this level will give the next higher distance digit. This is repeated a number of times until the distance is resolved.

illustrates three frequencies each folded out to show a continuous EDM-reflector-EDM path:

f1 = 10xf2; f2 = 10xf3

Multiple frequencies

Example

The following table shows the length of the last partial wave for each of 4 different wavelengths. What is the total distance?

λ, ft10.00 ft100.0 ft1000. ft10,000 ft

p, ft3.6953.74548450

dist, ft

The digits in bold represent the digits added to the distance as a result of each partial wavelength.

λ, ft 10.00 ft100.0 ft1000. ft10,000 ft

p, ft3.6953.74548450

dist, ft3.6953.69453.698453.69

The total distance is 8453.69 feet. The distance from the EDM to the reflector is 8453.69/2 = 4226.84 ft

Distance Reduction

An EDM measures the line of sight distance between the instrument and reflector. This is a slope distance and not horizontal unless the EDM and reflector are at the same elevation.

Slope Distance

In order to determine a horizontal or vertical distance additional information is needed. Combining an EDM with a digital theodolite results in a Total Station Instrument (TSI). When distance measurement is made, the TSI measures the slope distance and a zenith angle.

Total Station Instrument

From these two measurements, the Horizontal and Vertical distances are computed by the instrument:

Eqn (III-2)

Eqn (III-3)

It's a little more complex than this and we'll discuss a refinement in the section on Errors.

Evolutionary sidebar

Early attempts to integrate EDMs with theodolites resulted in some pretty interesting (and bizarre) hybrid instruments. When EDMs were first affordable a typical procedure a surveyor used would be: (1) measure a zenith angle with a theodolite, (2) remove the theodolite from the tripod and mount the EDM (often using the same tribrach to maintain the same setup) and measure the slope distance, and, finally (3) manually reduce the slope distance to horizontal.As EDMS became more affordable and smaller, other integration methods appeared.EDMS were placed in yokes mounted to a theodolite's standards. The vertical angle would be measured with the theodolite, and recorded or manually entered into the EDM. The slope distance would be measured with the EDM. Slope would be reduced to horizontal either manually or by the EDM if it could accept angle input.The advantage of this mounting method was that the EDM's measuring center was always vertically above the same point - it did not change position as it was elevated or depressed to sight the

prism. The disadvantage was that if the zenith angle was measured to the center of the prism an offset error was introduced because the signal path and line of sight weren't coincident.Another mounting method placed the EDM on top of, and later above and below, the theodolite telescope. Measurement and slope reduction was similar to that of a yoke-mount EDM.This method had the same disadvantage as the yoke mount plus two additional ones: (1) It shifted the measuring center of the EDM as the zenith angle changed (necessitating more computations), and, (2) it stressed the telescope mount and lock which were not designed for the additional eccentric weight.It wasn't until the digital theodolite was developed that the EDM could be seamlessly integrated with an angle measuring device: the Total Station. This has become the primary instrument for most surveyors and represents the latest evolutionary step of the EDM. For the rest of this chapter, we will discuss distance measurement with a TSI.

Reflector

Any surface capable of reflecting the electro-optical signal will allow distance measurement. However, the more efficient the reflector, the stronger the returned signal and the longer distance which can be measured. Efficiency includes amount of signal reflected along with the direction of its return path. For example, while a flat mirror reflects most of the signal, if it is not perpendicular to the incoming path, the signal will be reflected away from the TSI.

Mirror perpendicular to signal path Mirror not perpendicular to signal path

Mirror Reflector

To overcome this problem, a corner cube prism is used as a reflector for most TSIs. A corner cube prism is based on a 45° right angle prism. This type of prism has the property that any signal which intersects its long

(hypotenuse) side will be reflected parallel to the incoming path even if the prism is not perpendicular to the signal path.

Prism perpendicular to signal path Prism not perpendicular to signal path

Prism Reflector

A typical corner cube prism uses a glass cylinder having three 45° facets at one end. This creates three right angle prisms all sharing the glass cylinder's flat front as their hypotenuse. From the front the facets appear as six radial segments:

Prism, front view

The result is a highly efficient reflector for both signal strength and direction. Efficiency can be increased by using multiple prisms - this results in more signal being reflected increasing distance range. Using a triple prism can increase range by 50-60% depending on atmospheric conditions.

Triple prism

Over short distances of a few hundred feet, other objects such as bicycle reflectors and reflective tape will also work. While not as efficient as a prism they have the advantage of being cheap.

Reflectorless Total Stations

The past decade has seen the introduction and maturation of reflectorless total stations. Their inherent advantage is the ability to measure distances to points not accessible with a prism. Their biggest drawback is their generally (much) shorter range. This is in large part dependent on surface reflectivity. However, most reflectorless instruments can also use a prism as a conventional TSI giving them greater flexibility. A reflectorless TSI uses short pulses of high energy laser light. This energy is considerably higher than that used by phase shift TSIs in order to get a return signal off low reflection surfaces. The instrument measures travel times of the laser pulses and from that can

determine the total instrument-surface-instrument distance.Because the laser pulses reflect off different surfaces, care must be exercised when pointing the instrument. This is especially critical when there are multiple surfaces at various orientations near the measurement point. Many instruments feature a built-in laser pointer which provides the operator a visual indication of where the measurement will be made.

WORKING PROCEDURE The TA will demonstrate how to use each of the total stations in the field.

That tangent locks do not need to be rotated more than ¼ of a turn tolock or unlock the circle. If you over-tighten the tangent locks when lockingthe circle, this will strip the lock assembly

Do not unlock the lower circleassembly, as this instrument does not function like a theodolite. Take the timeto learn which screws adjust which orientations.

Take the instrument out of the box and insert the battery into the slot on theside of the instrument.

Put the instrument back in the box, lock the latches, and head for the NorthLawn. Use this checklist to remember the point-to-point procedure. Setup and level the instrument over the point. Backsight the previous point with a plumb bob or prism. Calculate and enter the azimuth to the backsight in the instrument. Foresight the next point and shoot the horizontal distance. Record the azimuth and distance to the foresight. Traverse to the next point. Set up the instrument over HAINES in a similar fashion to setting upthe theodolite. Make

sure you are directly over the station and the instrument islevel. Turn the instrument on and index it. Turn the instrument and backsight to station ECKL. Be sure to lock the motion of the

instrument. A proper alignment will look like this but withoutthe target board: Calculate and enter the appropriate backsight azimuth. This stepaligns the total station so

that the angle indicated on the total stationcorresponds to the azimuth. There is a different method to do this depending onwhich total station you are using. Your TA will demonstrate to your groupwhat to do. PAY ATTENTION to how it is done.

With the rodperson holding the pole in the center of the foresight point, turn the angle to your first foresight point, which is one of your parcelcorners. Note that the horizontal angle on the total station will indicate theazimuth of the foresight. Allow the rodperson to plumb the pole, and then sightthe center of the prism.

‘Shoot’ the distance to the foresight. Note that we are recording thehorizontal distance. Again, the methods differ so PAY ATTENTION whenyour TA shows you how to do it.7.Record the azimuth and distance to the foresight.

Traverse to the next point (which will be your previous foresight).Repeat the procedure beginning at Step 1.

Complete the traverse by recording the closing point, which should be the first parcel corner you collected from HAINES.

Calculate the closure of your parcel as learned in class. You shouldhave a loop precision of better than 1/7,500.

We were assigned to take the equipment to be brought into the area of the purpose of measuring the surface area of the land.

We find an appropriated area and draw position. We measured between picket to picket with 20mm spacing. When finished measuring the distance between the pickets,we start measured the distance

between pickets wit iron pickets at a distance of 5mm. Next we put the device level at an angle of 90 degree from the first point of picket. Then the device level is placed in the right direction to get the reading of staff. This method is done in the same way as much as 5 times.

Perform reconnaissance survey and mark stations with picket The Station can be set up by open traverse or closed traverse which started from a TBM or BM and ended at the same or different TBM or BM

Start observation with observe to a height reference point known as mean sea level ( MSL ) called Bench mark (BM) or Temporary Bench Mark ( TBM ) You can mark BM or TBM as station 1 or you can mark others station as station 1.

Manage temporary adjustment between station 1 and 2 and get staff reading in in station 1 as back sight ( BS ) view and fore sight view (FS) in station 2. Distance between BS and FS must be almost equal.

When making observation between Station 1 and 2 observe for 3 or 4 intermediate sight ( IS ) for checking purposes. Repeat step 5 to 7 until the leveling work revert to station 1.

The final position of staff must at point that we know the value of the reduced level. This is very important because fieldwork work must begin and ends on point that known the reduced level. If not it was impossible to detect the misclosure.

Only backsight, intersight, foresight and marks reading will be acquired in the fieldwork First reading that called BS is obtained from station that first once namely station 1 or BM

and marked in Backsight column and being recorded as BM in marks column if there is intersight reading write the value in Intersight column where only one columns for

a value and write any recognition to that value in marks column Then for the last one, take foresight reading and write in foresight column and marks it Then, do temporary adjustment in L2 and read BS on station 2, so station 2 will be having

two readings and it called change point. The value that been obtained will be included inside BS column a row of with FS value that taken from earlier station

Finish the intersight and foresight reading to station 3 Transfer instrument to L3 and repeat step v & vi but this time no intersight taken, so to

write the value just jump off the intersight column The others column will be filled by ccalculation the reduced level of each point can be calculate using the value of rise & fall. If the staff

reading on the first point is more than the staff reading on the next point called Rise and if the staff reading on the first point is less than that on the next point called fall.

The arithmetic check is to ensure the fieldwork is correct. There are three Arithmetic checks in this method:

Σ (Backsights) – Σ (Foresights) R.L Last - R.L First Σ (Rises) - Σ (Falls) The reduced levels of points are obtained by calculating the reduced levels of the plane of

collimation for each set up of the instrument. The height of collimation is obtained by adding the staff reading, which must be a Backsight,

to the known R.L. of the point on which the staff stands. All other readings are deducted from the height of collimation, until the instrument setting is

changed. Where upon the new height of collimation is determined by adding the backsight to the R-L. at the change point

There are two Arithmetic checks in HPC method: Σ(Backsights) - Σ (Foresights) R.L Last. - R.L. First

DISCUSSION/SUGGESTION As the discussions of this leveling fieldwork practical, my friends and I have gone through a lot of new and useful experiences. First of all, we had learned on how to level an empty land by using the

leveling equipments. This was my first time knowing using and handling such equipments. Moreover, we also learned to be patient in adjusting the bubble to the center of the circle. Although it was testing my patient but with the help of my group members I managed to balance the automatic level. However, we also faced some problems some problems when was leveling, it was very difficult for us to measure the incline land surface using the automatic level. This was because, the bubble was very difficult to position it into the center of the circle by 360° rotation. Furthermore, there are some suggestions on how to make this leveling fieldwork practical easier and faster. First of all, the automatic level have to change to digital level, so that the leveling practical would be much more easier and accurate. Besides, the leveling fieldwork area should be quite plane surface, so that the leveling practical would be more easy and can end up quickly. Relatively quick collection of information. Advantages of Total Station Surveying .Multiple surveys can be performed at one set-up location.Easy to perform distance and horizontal measurements withsimultaneous calculation of project coordinates (Northings, Eastings,and Elevations).Layout of construction site quickly and efficiently.Digital design data from CAD programs can be uploaded to datacollector.Vertical elevation accuracy not as accurate as using conventionalsurvey level and rod technique.Horizontal coordinates are calculated on a rectangular grid system.However, the real world should be based on a spheroid andrectangular coordinates must be transformed to geographiccoordinates if projects are large scale.Examples : highways, large buildings, etc.As with any computer-based application “Garbage in equalsGarbage out”. However, in the case of inaccurate constructionsurveys “Garbage in equals lawsuits and contractors claims for extras.”Disadvantages of Total StationSurveying.Daily survey information can also be quickly downloaded into CADwhich eliminates data manipulation time required using conventionalsurvey techniques.

CONCLUSIONAs the conclusion of this leveling fieldwork practical, the data that we obtained from the leveling using the automatic level were calculated and booked in correct form of data table. Those data were used to plot the profile and cross sections (1 - Longitudinal & 6 - Cross Section ) by using the Rise and Fall method. These plotting can decide the most suitable and economic levels and gradients in longitudinal section and in the traverse direction. It is also help to locating the places of cut, fills or neither cut nor fills occurs. Furthermore, the data that we obtained can be also used to plot contour section by using the method of Height of Collimation. The plotted contour shows lines which join the points that have the same height above or below the datum of a particular area (fieldwork). By doing this leveling fieldwork practical, my friends and I had learned a brand new experience on how to level an empty land by using the leveling equipments correctly and also how to book in the data in correct manner.In this work a systematic methodology in collecting and reducingfield data to obtain planimetric and contour maps simultaneously. This method should reduceerror and time of field work. A formula is derived to be used for correcting errors in elevationresults.The contour map produced by this work shows high degree of fidelity. The 3Dversion was produced by draping the satellite photographs obtained from Google Earth ontothe elevation data of the selected region. It shows a great deal of details and improves theappearance of contour map.It should be emphasized that recently there are new developments in technologies of total stations that may improve performance. These are ranging from reflectorless, robotic tosmart stations. However, their prices are considerably higher.

REFFERANCES

Ukur tanah, Ramsay JP Wilson (translated) by Sakdiah Basiro-Skudai ;Johor :UTM ,1995. Surveying : principles & Application 8^th Edition ,Barry F .kavanagh,New Jersey ,Pearson

Education,2009. Elementary Surveying 〖12〗^th Edition, charles D. Ghilani & Paul R .Wolf,New

Jersey,Pearson edUTION 2008. Geomatics,Barry F .Kavanagh , New Jersey ,Pearson Education, 2002. Survey Engineering 1 (for polytechnic students), edition 2013- written by MOHD FAHMI BIN

ABD. RAZAK-, received higher education from UTM in Surveying Skills. Surveying- written by GURUCHARAN SINGH; Head of Department,

Department of Civil Engineering Bikaner (Rajastan) – JAGDISH SINGH; M.E (Civil), Rajastan Water Pollution Control Board Alwar (Rajastan).

Surveying Principles and Applications, seventh edition – BARRY F. KAVANAGH; Seneca Collage Emeritus, Upper Saddle River, New Jersey Columbus.

Surveying seventh edition – A BANNISTER; MC, MSc, CEng, FICE – S RAYMOND; MSc, PhD, DipTP (Manchester), CEng, FICE, MRTPI, FIHT (Consulting Engineer).