CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
CE6404 SURVEYING II L T P C 3 0 0 3 OBJECTIVES:
This subject deals with geodetic measurements and Control Survey methodology and its adjustments. The student is also exposed to the Modern Surveying. UNIT I CONTROL SURVEYING 9 Horizontal and vertical control – Methods – specifications – triangulation- baseline – instruments and accessories – corrections – satellite stations – reduction to centre-
trigonometrical levelling – single and reciprocal observations – traversing – Gale‟s
table. UNIT II SURVEY ADJUSTMENT 9 Errors Sources- precautions and corrections – classification of errors – true and most probable values- weighed observations – method of equal shifts –principle of least squares -0 normal equation – correlates- level nets- adjustment of simple triangulation networks. UNIT III TOTAL STATION SURVEYING 9 Basic Principle – Classifications -Electro-optical system: Measuring principle, Working principle, Sources of Error, Infrared and Laser Total Station instruments. Microwave system: Measuring principle, working principle, Sources of Error, Microwave Total Station instruments. Comparis on between Electro-optical and Microwave system. Care and maintenance of Total Station instruments. Modern positioning systems – Traversing and Trilateration. UNIT IV GPS SURVEYING 9 Basic Concepts - Different segments - space, control and user segments - satellite configuration - signal structure - Orbit determination and representation - Anti Spoofing and Selective Availability - Task of control segment – Hand Held and Geodetic receivers –data processing - Traversing and triangulation. UNIT V ADVANCED TOPICS IN SURVEYING 9 Route Surveying - Reconnaissance - Route surveys for highways, railways and waterways - Simple curves – Compound and reverse curves - Setting out Methods – Transition curves - Functions and requirements - Setting out by offsets and angles - Vertical curves - Sight distances- hydrographic surveying – Tides - MSL - Sounding methods - Three-point problem - Strength of fix - Sextants and station pointer- Astronomical Surveying – field observations and determination of Azimuth by
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
altitude and hour angle methods – fundamentals of Photogrammetry and Remote Sensing
TOTAL: 45 PERIODS OUTCOMES: On completion of this course students shall be able to
Understand the advantages of electronic surveying over conventional surveying methods
Understand the working principle of GPS, its components, signal structure, and error sources
Understand various GPS surveying methods and processing techniques used in GPS observations
TEXT BOOKS: 1. James M. Anderson and Edward M. Mikhail, "Surveying, Theory and Practice", 7th Edition, McGraw Hill, 2001. 2. Bannister and S. Raymond, "Surveying", 7th Edition, Longman 2004. 3. Laurila, S.H. "Electronic Surveying in Practice", John Wiley and Sons Inc, 1993. REFERENCES: 1. Alfred Leick, "GPS satellite surveying", John Wiley & Sons Inc., 3rd Edition, 2004. 2. Guocheng Xu, "GPS Theory, Algorithms and Applications", Springer - Berlin, 2003.
3. Satheesh Gopi, rasathishkumar, N. madhu, “Advanced Surveying, Total Station GPS and Remote Sensing" Pearson education , 2007
UNIT I CONTROL SURVEYING
Two Marks:
1. What is control surveying?
Control surveying is performed to achieve higher accuracy data of horizontal
and vertical coordinates.
2. What are the components of control surveying ?
Control surveying consists of research, measurements, calculations and reports
detailing the horizontal and vertical reference systems established for the survey.
3. What is the difference between a theodolite and tacheometer
A theodolite is a precision instrument for measuring angles in the
horizontal and vertical planes. Theodolites are used mainly for surveying
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
applications such as in fields like meteorology and rocket launch technology.
Theodolites may be either transit or non-transit. Transit theodolites (or just
"transits") are those in which the telescope can be inverted in the vertical plane,
whereas the rotation in the same plane is restricted to a semi-circle for non-
transit theodolites. Some types of transit theodolites do not allow the
measurement of vertical angles.
Tacheometry is a system of rapid surveying by which the positions, both
horizontal 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.
4. Define Tachometry?
Tachometry is a branch of angular surveying in which the horizontal and vertical
distances (or) points are obtained by optional means as opposed to the ordinary slower
process of measurements by chain (or) tape.
5. Define Tachometer
It is an ordinary transit theodolite fitted with an extra lens called analytic lens. The
purpose of fitting the analytic lens is to reduce the additive constant to zero.
6. Define Analytic lens
Analytic lens is an additional lens placed between the diaphragm and the objective at a
fixed distance from the objective. This lens will be fitted in ordinary transit theodolite. After
fitting this additional lens the telescope is called as external focusing analytic telescope. The
purpose of fitting the analytic lens is to reduce the additive constant to zero.
7. What are the advantages of an anallactic lens used in tacheometer
Anallatic lens: Additional convex lens is provided between the eye piece and
the object glass at a fixed distance from the object glass. The purpose of
providing anallatic lens is to make additive constant (f+d) exactly zero.
Anallatic lens is provided in external focusing telescope, not required in
internal focusing telescope.
Advantage
it simplifies the calculation by making the additive constant ‘0’.
Therefore, there is only one constant which is multiplying constant.
Distances are directly calculated by multiplying the difference of
stadia hair readings by 100.
Disadvantage
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
Brightness of the image is much reduced due to absorption of light.
8. Define Substance bar
A Substance bar is manufactured by Mr. Kern. The length of the substance bar is2m (6ft)
for measurement of comparatively short distance in a traverse. A Substance bar may be used as a
substance base. The length of the bar is made equal to the distance between the two targets.
9. What are the merits and demerits of movable hair method?
Merits - Long sights can be taken with greater accuracy than stadia method. The error
obtained is minimum.
Demerits - The computations are not quicker Careful observation is essential
10. Fixed hair method - In this method, the stadia wires are fixed (or) fitted at constant
distance apart.
11. Staff intercepts - The difference of the reading corresponding to the top and bottom
stadia wires.
12. Stadia intercept - The difference of the distance between the top and bottom
cross hairs.
13. Sub tense method
In this method stadia interval is variable. The staff intercept is kept fixed
while the stadia interval is variable.
14. The tangential method
In this method, the stadia hairs are not for taking readings. The readings
being taken against the horizontal cross hair.
15. What are the systems of tachometry measurements?
The stadia system
The tangential system
Measurement by means of special instrument.
16. What are the three types of telescope used in stadia surveying?
(1) The simple external-focusing telescope
(2) the external-focusing anallactic telescope (Possor`s telescope)
(3) the internal-focusing telescope.
17. What are the types of stadia system?
Fixed hair method And Movable hair method
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
18. What is base net?
In advanced surveying like GPS is done by fixing some known points commonly
called as control points or control stations inorder to get the x,y,z coordinates
with higher accuracy.
19. What is the principle of stadia method?
The method is based on the principle that the ratio of the perpendicular to
the base is constant to similar isosceles triangle.
SIXTEEN – MARK QUESTIONS
1. What are the different corrections to be applied while measuring baseline in geodetic surveying? 2. A steel tape 30m long, standardized at 10° c with a pull of 100N was used for measuring a baseline. Find the correction per tape length, if the temperature at the time of measurement was 20°c and pull applied was 150 N. Density of steel = 3000 kg/m3 . Weight of tape=5.88N. 3. What is meant by a “satellite station”? Explain briefly. 4. In a trignometrical measurement of the difference in level of two stations P and Q, 10480 m apart, the following data were obtained. Instrument at P, angle of elevation of Q = 0‟15” Instrument at Q, angle of depression of P = 3‟ 33” Height of instrument at P = 1.42 m. Height of instrument at Q = 1.45 m. Height of signal at P = 3.95 m. Height of signal at Q = 3.92 m. Find the difference in level between P and Q and the curvature and refraction correction. 5. From an eccentric Station S, 12.25 meters to the west of the main station B, the following angles were measured BSC = 760251; CSA = 540321 2011. The stations S and C are to the opposite sides of the line AB. Calculate the correct angle ABC if the lengths AB and BC are 5286.5 and 4932.2m respectively. 6. What are the methods of measurement of the base line and explain any two with neat sketch. 7. A steel tape is 30 m long at a temp of 15ºc when lying horizontal on the ground. Its c/s area is 0.08 cm2 and weight of 18.kg (18N) and. Co-efficient of expansion is 117 x10-7/ºc. The tape is stretched over 3 supports which are at the same level and
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
at equal intervals. Calculate the actual length between the end graduations under the following conditions. Temp = 25ºc, Pull -180 kg, E = 2.1 x 105 N/cm2. 8. Explain in detail about Horizontal control & its methods andVertical Control & its Methods. 9. State the factors to be considered while selecting base line and also explain with neat sketches how to extend the base line in the field. 10. Explain in detail about the Classification of triangulation system. 11. What is mean by triangulation adjustment? Explain the different conditions and cases with sketches. 12. Write short notes on: (1) selection of site for base line (2) Satellite station 13. What are the different methods by which the difference in elevation could be determined? Name the corrections to be applied.
UNIT-II SURVEY ADJUSTMENT
2-MARKS
1. Define Systematic Errors
2. State Accidental Errors.
3. Write the classification of Observer Quantity.
4. What do you mean by Conditioned Quantity?
5. What do you mean by Direct Observation?
6. State Weight of an Observation.
7. What do you mean by Observed value of a Quantity?
8. Define Normal Equation.
9. Define most probable Errors.
10. Explain Declination.
11. State hour angle.
12. What is Celestial Horizon?
13. What are the celestial poles and equator?
14. Define Sensible horizon.
15. Define Observers Meridian.
16. What is a level net?
17. Mention the adjustment of simple triangulation network?
18. What is a simple triangulation network?
19. What is contour gradient? Where it is used?
20. Explain the object of preparing a contour map.
21. What is a true value?
22. Define most probable values.
16-MARKS
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
1. What are the temporary adjustments of dumpy level? How is it done?
2. What is reciprocal leveling and why is it employed? What errors will be eliminated by
this?
3. Enumerate the principle of least squares as applied to observations of equal weight and
to those for which different weights are assigned.
4. Explain the methods of correlates.
5. What do you mean by station adjustment? Explain.
6. The following are the three angles α, β and γ observed at a station P closing the
horizon, along with their probable errors of measurement. Determine their corrected
values α = 78o 12’ 12” ± 2”, β = 136 o 48’ 30” ± 4” , γ = 144 o 59‟ 08” ± 5”.
7. What do you mean by figure adjustment? Explain .
8. Find the most probable values of the angles A, B and C from the following
observations at a station P using method of differences.
a. A = 38 o 25’ 20” wt.1
b. B = 32 o 36’ 12” wt.1
c. A +B = 71 o 01’ 29” wt .2
d. A + B+ C = 119 o 10’ 43” wt.1
e. B + C = 80 o 45’ 28” wt.2
9. Form the normal equation for x, y, z in the following equations.
a. 3X+3Y+Z-4=0
b. X+2Y+2Z-6=0
c. 5X+Y+4Z-21=0
10. Also form the normal equation, if weights of the equations are 2, 3 and 1 respectively.
11. The following angles were measured at a station O so as to close the horizon
a. A=8304212811.75 wt.3
b. B=10201514311.26 wt.2
c. C=9403812711.22 wt.4
d. D=7902312311.77 wt.2
12. Adjust the angles by method of correlates.
13. Explain in detail about errors sources and error classification.
14. What are the precautions and correction can be applied in error reduction.
15. How are normal equations formed in theory of errors?
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
16. List three types of errors occur in measurement.
UNIT-III TOTAL STATION SURVEYING
TWO MARK QUESTIONS:
1. What is a Total Station Surveying?
Total station surveying - defined as the use of electronic survey equipment
used to perform horizontal and vertical measurements in reference to a grid
system (e.g. UTM, mine grid)
2. What is an Total Station Instrument?
A Total Station is a modern surveying instrument that integrates an
electronic theodolite with an electronic distance meter. Total Stations use
electronic transit theodolites in conjunction with a distance meter to read any
slope distance from the instrument to any particular spot. They are hence
two essential surveying instruments in one and when used with other
technology such as mapping software are able to deliver the 'total' surveying
package, from measuring to mapping.
3. What are the components used in Total Station Surveying
The components used in Total Station Surveying are :
a) Total Station (and tripod) b) Electronic Notebook c) Prism (and prism pole) d) Computer interface e) Batteries and radios
4. What are the types of Total Station Surveying
Slope Staking , Topographic surveys, Construction project layout , Leveling
Traverse surveys and adjustments, Building Face Surveys, Resections , Areas,
Intersections, Point Projections, Taping from Baseline.
5. What are the sources of Errors
Calibration of total stations
Horizontal collimation (or line of sight error)
Tilting axis error
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
Compensator index error
Vertical Collimation (of vertical index) Error
Total Station Calibration Procedure
Instrumental Distance Errors
Atmospheric Effects
6. What are the advantages of Total Station
Relatively quick collection of information
Multiple surveys can be performed at one set-up location.
Easy to perform distance and horizontal measurements with simultaneous
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 data collector.
Daily survey information can also be quickly downloaded into CAD which
eliminates data manipulation time required using conventional survey
techniques.
7. What are the disadvantages of Total Station
Vertical elevation accuracy not as accurate as using conventional survey level
and rod technique.
Horizontal coordinates are calculated on a rectangular grid system.
However, the real world should be based on a spheroid and rectangular
coordinates must be transformed to geographic coordinates if projects are
large scale.
Examples : highways, large buildings, etc.
As with any computer-based application “Garbage in equals
Garbage out”. However, in the case of inaccurate construction surveys “Garbage
in equals lawsuits and contractors claims for extras.”
8. What is the working principle of Electro-optical system or EDM
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.
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
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.
9. What is Microwave total station instrument
Microwave total station instrument is a 3-3.5 GHz microwave frequency. Measurement signal used by microwave devices Measurement signal used by microwave devices consists of frequency modulation (FM) consists of frequency modulation (FM) superimposed on the carrier wave, Operates on phase--shift principle, Corresponds to wavelengths of 1--8.6 mm, <60 km range, 2 portable identical units 2 portable identical units -- master, remote.
10. Comparison between electro-optical and microwave total station instrument
Electro-optical instrument use :
the velocity of light waves to determine the distance between two points. both the visible lights (wavelength between 0.4-0.7) and the infrared lights (wavelength between 0.7-1.2). Infrared light much preferable because of the long wavelength. Source of light: Mercury lambs, Tungsten.
Microwave total station instrument uses:
Wave length λ = distance travelled during the period of one cycle. V = Velocity of emission F = Frequency in HZ
SIXTEEN – MARK QUESTIONS
1. Explain in detail about Electromagnetic Spectrum and its applications 2. Explain in detail about the properties of electromagnetic waves. How are they useful in measuring of distances? 3. Explain in detail about the different types of EDM 4. Explain the working principle of EDM
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
5. Why phase comparison and modulation is preferred over time measurement in EDM 6. Explain the working principle of “Tellurometer” 7. Explain the working principle of “Geodimeter” 8. Explain the working principle of “Wild Distomats” 9. Explain in detail about the sources of errors in Total station and EDM. 10. How is Traversing and Trilateration done using Total station?
11. Explain in detail about the fundamental measurements of the Total Station.
UNIT- IV GPS SURVYING
TWO MARK QUESTIONS:
1. Celestial sphere
It is an imaginary sphere on which the stars appear to lie or to be studded is
known as the Celestial sphere.
2. Zenith (z)
It is the point on the upper portion of the celestial sphere marked by plumb
line above the observer. It is the point on the celestial sphere immediately above the
observer’s station.
3. Nadir (Z’, or, N):
It is the point on the lower portion of the celestial sphere marked by plumb
line below the observer. It is the point on the celestial sphere vertically below the
observer’s station.
4. Celestial Horizon
It is also called true or Rational horizon or geocentric horizon. It is the great
circle traced upon the celestial sphere by that plane which is perpendicular to the
zenith–Nadir line and which passes through the centre of the earth.
5. The terrestrial poles and equator
The terrestrial poles are the two points in which the earth’s axis of notation
meets the earth’s sphere. The terrestrial equator is the greet circle of the earth, the
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
plane of which is at right angles to the axis of notation. The two poles are
equidistant from it.
6. The celestial poles and equator
If the earth’s axis of rotation is produced indefinitely, it will meet the celestial
sphere in two points called the North & South celestial poles (P and P’).The celestial
equator is the great circle of the celestial sphere in which it is intersected by the
plane or terrestrial equator.
7. Sensible horizon
It is a circle in which a plane passing through the point of observation and
tangential to the earth’s surface intersects with celestial sphere. The line of sight of
an accurately leveled telescope lies in this plane.
8. Visible horizon
It is a circle of contact, with the earth, of the cone of visual rays passing
through the point of observation.
9. Vertical circle
A vertical circle of the celestial sphere is great circle passing through the
zenith and nadir. They all cut the celestial horizon at right angles.
10. The Observers Meridian
The meridian of any particular point is that circle which passes through the
zenith and nadir of the point as well as through the poles.
11. Prime vertical:
It is the particular vertical circle which is at right angles to the meridian and
which therefore passes through the east & west points of horizon.
12. Latitude (θ)
It is the angular distance of any place on the earth’s surface north or south of
the equator, and is measured on the meridian of the place. It is also defined as the
angle between the zenith and the celestial equator.
13. The co-latitude
The co-latitude of a place is the angular distance from the zenith to the pole.
It is the complement of the latitude and equal to (900).
14. The longitude
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
The longitude of a place is the angle between a fixed reference meridian
called the prime or first meridian and the meridian of the place.
15. The altitude
The altitude of celestial or heavenly body (i.e., a sun or star) is its angular
distance above the horizon, measured on the vertical circle passing through the
body.
16. The co-altitude or zenith distance (z)
It is the angular distance of heavenly body from the zenith. It is the complement
of the altitude.
17. The Azimuth
The azimuth of a heavenly body is the angle between the observer’s meridian
and the vertical circle passing through the body.
18. The Declination
The declination of a celestial body is angular distance from the plane of the
equator, measured along the star’s meridian generally called the declination circle.
Declination varies from 00 to 900, and is marked + or – according as the body is
north or south of the equator.
19. Hour circle
Hour circles are great circles passing through the north and south celestial
poles. The declination circle of a heavenly body is thus its hour circle.
20. The hour angle
The hour angle of a heavenly body is the angle between the observer’s
meridian and the declination circle passing through the body. The hour angle is
always measured westwards.
SIXTEEN – MARK QUESTIONS
1. Calculate the sun’s azimuth and hour angle at sunset at a place in latitude
42°30’ N, when is declinations is
(i) 22°12’ N and (ii) 22°12’ S
2. Enumerate and explain the relationships between the coordinates of celestial
sphere.
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
3. Explain the method of prediction of tide at a place using non-harmonic
constants
4. Explain the procedure to use fathometer in ocean sounding.
5. Explain the method of plotting of plain metric maps by radial method.
6. What are the applications of photogrammetry?
7. Calculate the azimuth of the sun and hour angle at sunset at a place in latitude
55 º N, when its declination is :
1. 20°N 2. 30°N 3. 15°S
8. A zenith pair observation of a star crossing the meridian was made to
determine the latitude of a place. Refraction correction = - R” cot α
Star Declination Altitude
X1 15°15’ 17” N 62°15’ 20” S
X2 70°43’ 13” N 62°17’ 30” N
Find R and the latitude of the place.
UNIT-V ADVANCE TOPICS IN SURVEYING
TWO MARK QUESTIONS
1. Hydrographic Survey
Hydrographic Survey is that branch of surveying which deals with the
measurement of bodies of water. It is the art of delineating the submarine levels,
contours and features of seas, gulfs, rivers and lakes.
2. Sounding
The measurement of depth below the water surface is called sounding.
3. Tides
All celestial bodies exert a gravitational force on each other. These forces of
attraction between earth & other celestial bodies cause periodical variations in the
level of water surface, known as tides.
4. Equilibrium Theory
The earth is covered all around by the ocean of uniform depth. The ocean is
capable of assuming the equilibrium.
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
5. Mean sea level
Mean sea level may be defined as the mean level of the sea, obtained by
taking the mean of all the height of the tide as measured at hourly intervals over
some states period covering a whole number of complete tides.
6. Fathometer
A fathometer is used for ocean sounding where the depth of water is too
much and to make a continuous and accurate record of depth of water below the
boat or ship at which it is installed.
7. Photographic Survey
It is also called photogrametry. It is a method of surveying in which plant or
maps are prepared from photographs taken from Suitable camera station. It is
divided into two. Terrestrial photography & Aerial photography
8. Photo theodolite
It is the combination of photo with theodolite and is used for taking
photographs & measuring the angles which the vertical plane of collimation makes
with the base line.
9. Stereoscopic pairs
It means two photos are obtained for a Single object from two point one at
each.
10. Parallax
In normal binocular vision the apparent movement of a point viewed first
with one eye and then the other is known a parallax.
11. Angle of Parallax
It is the angle of convergence of the two rays of vision.
12. Stereoscopic fusion
If a pair of photographs is taken of an object from two slightly different
positions of the camera and then viewed by an apparatus which ensures that the left
eye sees only the left-hand picture & right eye is directed to the right hand picture,
the two separate images of the object will fuse together is the brain to provide the
observer with spatial impression. This is known as a Stereoscopic fusion.
13. Stereo pair
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
The pair of two such photographs is known as stereo pair. The effect of
distortions exist in a single photograph may be eliminated through a large extend of
stereo pairs.
14. Parallax bar
A parallax bar used to measure difference of two points, consists of a bar
which holds a fixed plate of transparent material near the left end and a movable
plate to the right end.
15. Floating mark
In parallax bar, when the two dots are viewed properly under a stereoscope
they fuse into a single dot called floating mark.
16. Mosaics
An assembly of getting series of overlapping photograph is called mosaic.
17. Types of EDM instrument
Tellurimeter
Geodimeter Distomats
18. Cartography
It is the marking and study of maps in all their aspects. It is an important
branch of graphics, since it is an extremely efficient way of manipulating, analyzing,
&expressing ideas, forms & relationships that occur in two & three dimensional
space.
19. Cadastral survey
Cadastral means, “Registration concern Land Survey”. It is of one of based on
national land survey based on land survey law.
20. Modulation
Amplitude modulation
In amplitude modulation, the carrier wave has constant
frequency & the modulating wave (the measurement wave) in
formation is conveyed by the amplitude of the carrier wave.
Frequency modulation
CE 6404 SURVEYING II IV SEMESTER
DEPARTMENT OF CIVIL ENGINEERING - SJCE
In the frequency modulation the carrier wave has
constant amplitude, while the frequency varies in proportion
to the amplitude of the modulation wave.
21. Methods of Measuring Velocity flow
Surface float
Sub surface float
Velocity ropes
Picot tube method
Current meter mean
SIXTEEN – MARK QUESTIONS
1. Derive the parallax equation for the ground coordinates of a point.
2. A pair of photographs was taken with an aerial camera from an altitude of 500
m above MSL. The mean principle base measured is equal to 90 mm. The
difference in parallax between two points is 1.48 mm. Find the difference in
height between two points if the elevation of the lower point is 500 m above the
datum. What will be the difference in elevation if the parallax difference is 15.5
mm?
3. Explain three point problem and strength fix in hydrographic surveying.
4. Explain cadastral surveying and its legal values.
5. Explain briefly components of hydrographic survey? 6. Comparison between Aerial photographs and maps 7. List the different methods of locating soundings. Explain any two methods. 8. Define stereoscope and list out the types of stereoscopes? 9. State the equipment used for soundings and explain them. 10. State stereoscope and explain briefly the basic types of stereoscopes. 11. Explain briefly about the Electro-Magnetic Distance measurement. 12. What is a three point problem in hydrographic surveying? What are the various solution for the Problems? Explain any one method. 13. Explain briefly the different methods of prediction of tides