surveying lab manua-KLUl 26-04
Contents
1. over one station and measure the horizontal distance verti distance to an adjacent station Duties for this exere the 4nstrument over one of the traverse stations Follow th scribed in item 2 above The note keeper in the atmospheric pressure and temperature From the manual ne the appropriate PPM setting and enter this setting into the total entering g the PPM constant into the total station Determine the prism offset constant This value will be 40 mm 30 mm or 0 mm depending on the reflector If m doubt consult the instructor Refer to the user s manual to determine the correct procedure for entering the prism offset constant into the total station e Review your instrument manual and make certain that the instrument is ready to operate If additional preparation is necessary perform such f Determine the procedure for measuring horizontal vertical and slope distance with your instrument Measure the horizontal H vertical V and slope S distances between the set up station and an adjacent station Things to Remember 1 j Rotate duties and repeat steps a through Some instruments do all three measurements in one operation Others require three separate operations Consult the instrument manual g Record these three measurements on the data sheet provided at the end of this practicum description Report all measurements in feet and meters The total station should be capable of providi2. The result is shown in Table Table Measurement of Horizontal Angle By Repetition Method bject Angle observ Number Initial Angle Final Angle on lean Mean ation of on Vernier Vernier Angle of Angle of readings Vernier Observatio gt A Face AOB Left Face A i AOB Right Mm 4 B Expt No 10 Date INTRODUCTION ON TOTAL STATION AND ITS VARIOUS PARTS Purpose To become familiar with the capabilities and general operation of a total station 4 instrument to become familiar with the procedure for setting up over a m and simple distance measurement s Eguipmen Field Notes Field notes will not be taken during this exercise I he orm n sheet provided at total station assigned to ve end of the practicum the end of this lab to compile the necessary inforst you for the practicum Hand in the complete period A Procedure 1 Orientation to the Total Stati by giving a general orientation to the total O in mind that each instrument is slightly different te for determining the correct operation procedure as it Each party will set the instrument on top of the table in tify parts as they are discussed Be careful with the q eveling the instrument Use of the optical plummet Use of the clamp and tangent slow motion screws of the horizontal circle motion lower motion and upper motion if appropriate and the vertical circle motion d Focus
3. object glass and focusing screw provided with focusing screw clamping j ti Ter er gra uated continuously from 0 to er in clock wise direction or it Bach quadrant 1 IS graduated from 0 to 90 in opposite directions ble the letter A and hence they sometimes known as A frames They are standards Plumb Bob Plumb Bob 1s suspended from the hook fixed bottom of central vertical axis Tripod Tripod is the stand in which the whole instrument rests At lower ends the legs are provided with pointed steel shoes READING THE VERNIER THEODOLITE The least count of the vernier is to be determined first Let least count of the vernier is 20 The main division of the main scale is of 1 Suppose it is divided into three parts Then each part accounts for 20 The vernier scale has 20 big and 60 small divisions F Least count d n 20 60 x 60 20 A Least count of one small division 20 Least count of one big division 20x3 60 1 After making the final adjustment for measuring the angle the 00 vernier scale 1s noted Suppose the arrow crosses 10 and 204 whi obtained from the main scale X of the arrow of the Suppose again that the first small division after 12 big div exaetl coincides with any of the main scale divisions Then the vernier reading is j Final Angle 10 20 12 20 10 4 PROCEDURE i 5 Consider Fig AOB 1s to be measured The following procedure is adop
4. so that the thumbs move either towards each other or away from each other until the bubble becomes centre 111 Turn the upper plate through 90 i e until the axis of level passes over the position of the third foot screw C Fig b Turn this foot screw until the bubble comes to centre IV Return to the upper plate through 90 to its original position Fig a and repeat the step 11 till the bubble comes centre V Turn back again through 90 and repeat the step iii vi Repeat the steps 11 and 111 until the bubble is central in both the positions ain in the vii Now rotate the instrument through 180 The bubble should be re centre of its run provided it is in correct adjustment The vertical xis will be truly vertical If not 1t needs permanent adjustment 3 ELIMINATION OF PARALLAX Parallax is a condition arising when the image formed by obj cts cross hairs Unless the parallax is eliminated accurate sighting i be eliminated in two steps 1 By focusing the eye piece 11 By focusing the objective f i By focusing the eye piece The aim of focusing eye piece 1 Point the telescope towards the sk objective and move the eye pi clearly and distinctly ii By focusing the obje ti Telescope is no towa 1 the object to be sighted and the focusing screw is turned unti ypears clear and sharp The image 1s formed in the 2 CP PIN 3 Fig Levelling 4 PROCEDURE i Set
5. the instrument at a convenient point and complete temporary adjustments ii Take BS reading on Temporary Bench Mark TBM iii Keep the staff at change point and enter the staff reading in FS column iv Shift the level and enter the staff reading in BS column v Repeat the process to cover all the points vi Apply arithmetical check A 4 OBSERVATIONS amp CALCULATIONS The staff readings are entered m levelling field book and the R Ls ined both by H I Method and Rise and Fall Method e The I staff reading from a set up 1s B S and the S reading 1s F S and all other readings are I S e In order to eliminate any error level shoul xactly mid way between BS and FS e If any point is above the line of ir entered as Ve Arithmetical Check X BS XFS Last RL First RL b Rise and Fall Method Remarks nl a4 o p N Q o Q 3 V lt First RL ar10us points are determined XBS XFS X Rise 5 RESULT The Reduce Expt No 9 Date MEASUREMENT OF HORIZONTAL ANGLES BY METHOD OF REPETITION AND MEASUREMENT OF VERTICLE ANGLES WITH THEODOLITE 1 AIM Measurement of the horizontal angle using theodolite by general 2 INSTRUMENTS Theodolite Tripod and Ranging rods 3 THEORY wise 1n the face left and face ee distinctive i To support the main part of the instrument
6. Expt No 2 Date DETERMINATION OF AREA OF POLYGON BY CHAIN AND CROSS STAFF SURVEY 1 AIM To determine the area of a given field with define boundary by conducting cross staff survey 2 INSTRUMENTS REQUIRED A Metric Chain of 20m 30m 1 no Tape 1 no Ranging rods 4 nos Arrows 10 nos and Cross staff 1 no 3 PROCEDURE F Fig Cross Staff Survey 4 Now the area is divided into a number of triangles rectangles and trapeziums 5 Calculate the area of triangles rectangles and trapeziums Area of triangle gt base height Area of trapezium a b 2 h Where a b Parallel sides of the trapezium h the perpendicular distance between them Sum of all the areas will give the total area of the given field ABCDEFG 4 OBSERVATIONS otal area 5 RESULT 4 The area of the given land Expt No 3 Date MEASUREMENT OF DISTANCE BY INDIRECT RANGING AND CHAINING OBSTACLES FOR BOTH CHAINING AND RANGING A chain line may be interrupted in the following situations I When chaining and vision are both obstructed Example Building II When chaining is free but vision is obstructed Example Rising Ground or Jungle III When chaining is obstructed but vision is free Example Pond or a River When chaining and vision are both obstructed Such a problem arises when a building comes acros manner Suppose AB 1s the chain line Two points C building as shown i
7. Lower Plate Scale Plate The lower plate is attached to the outer axis The lower plate carries a horizontal circle at its level edge and 1s therefore also known as scale plate This plate is circular in shape and bevelled at edges It is graduated from 0 to 360 in the clockwise direction The lower plate carries lower clamp screw and lower tangent screw When the lower clamp 1s tightened the lower plate 1s fixed to tribach of the leveling head On turning the lower tangent screw the lower plate can be rotted slightly Usually the size of the theodolite 1s represented by the size of the scale plate Upper Plate Vernier Plate The upper plate is attached to the inner axis and carries two verniers with magnifiers at extremities diametrically opposite The upper plate supports the Standards A frames It carries an upper clamp screw and corresponding upper tangent screw for purpose of accurately fixing upper plate to lower plate aasa f A On clamping the upper clamp and unclamping the lower clamp the lower f instrument can rotate on its outer axis without any relative motion betwee however lower clamp is clamped and upper clamp is unclampe instrument can rotate on its inner axis Plate Bubble Tube i The Plate Bubble Tube is provided on the upper plate It enat instrument Telescope The telescope is an integral part of a vernier theodol plane about horizontal tunnion axis The telescope eyepiece
8. cked in the following ways There may be two cases Alternatively The pond may also be crossed by forming a triangle as shown in Fig 3 A point C 1s selected on the chain line The perpendicular CE 1s set out at C and a line ED is suitably taken The distances CE and ED are measured So CD ED CE E Expt No 5 Date MEASUREMENT OF BEARINGS OF SIDES OF TRAVERSE WITH PRISMATIC COMPASS AND COMPUTATION OF CORRECT INCLUDED ANGLE 1 AIM 2 INSTRUMENTS REQUIRED Prismatic Compass Tripod Tape Chain Arrows and Ranging Rods 3 SKETCH C Fig Closed Traverse 4 FIELD APPLICATIONS This type of surveying is useful for ponds etc 5 PROCEDURE TEMPORARY STATION ADJUSTMENTS M The following Temporary Station Adjustments are to be done at each station is set up Compass 1 CENTERING 1 LEVELLING 111 FOCUSING i CENTERING Normally the compass is cente from the bottom of the compass box Centerin ii LEVELLING Leveling is done box is placed in such a way ri touching either bottom cover on top 11 111 he instrument to subsequent station B perform all the temporary adjustments t fixing the instrument sight the next station C and observe the reading which gives the fore bearing of BC and measure the distance BC And now sight the previous station A and observe the reading which gives the back bearing of AB vi Repeat
9. n Fig 6 Egual perpendi u and DD are erected The line CiD 1s extended until the building is crossed On the e ne two points E and F are selected BUILDING b zrn kok B Fig Expt No 4 Date MEASUREMENT OF DISTANCE BY INDIRECT RANGING AND CHAINING OBSTACLES FOR EITHER CHAINING OR RANGING I When chaining is free but vision is obstructed Such a problem arises when a rising ground or a jungle interrupts the chai stations are not intervisible There may be two cases Case 1 The end stations may be visible from some intermed ground In this case Indirect Reciprocal Rangi chaining 1s done by stepping method Let AB be the actua of interruption by chain line be extended up to R A point P is nd a random line PT 1s taken 1n a suitable direction RANDOM LINE Fig 1 The perpendicular at C meets the chain line at C Theoretically the perpendiculars at D and E will meet the chain line at D and E1 Now the distances Pc PD PE and CC are measured Fig 1 From triangles PDD and PCC DD CU PD PC CC DD xPD gt gt 1 PC Again from triangles PEE and PCC EE CC PE PC CC EB X PE PC From 1 and 2 the lengths DD and EE are eg distances are measured along the perpendicu should lie in the chain line AB which can be e Distance PE Such a problem arises when a pond or a ri A the chain line The situation may be ta
10. n using Radiation Method 2 INSTRUMENTS Plane table Drawing sheet Alidade Spirit level Compass U fork or Plumbing fork with plumb Bob 3 THEORY Radiation method is suitable for locating the object rays are drawn from the station to the objects and thc station In this method are measured and plotted to any suitable scale a es from the station to the objects ve rays 4 PROCEDURE i Suppose P is a station on the greu vhere the objects A B C and D are visible The plane table is set over station P A drawing sheet is fixed on the table which 1s fixed on the table which is th centered A point p is selected on the sheet to represent the station P 11 The north line N n rked on the _ hand top corner of the sheet with compass 111 iv The obtain Trough Compass Fig Locating objects from a Single Station Radiation Method Expt No 7 b Date PLANE TABLE SURVEYING METHODS b INTERSECTION METHOD AIM To locate inaccessible points by the intersection of the rays drawn from two stations INSTRUMENTS Plane table Drawing sheet Alidade Spirit level Compass U fork or Plumbing fork with plumb Bob THEORY Intersection method is suitable for locating 1 ina from two instrument stations r by the intersection of the rays PROCEDURE 1 Suppose A and B are twi required to fix the position 11 Hex is shifted and centered over stati
11. ng both units h Turn off the total station Return the leveling screws to their neutral positions Remove it from the tripod set up and place it in the case 1 Move to an adjacent station in the traverse until all party meme have the opportunity to set up over a point level the instrument 1 the instrument and measure the H V and S distances 66299 1 Never transport the total station while attached to thet the instrument and place it in the case when mov the next See figure to right for one acceptabl ying equipment t dust and dirt It is not a good idea to remove a batt ry from af instrument while the instrument is on Such action may ca mage to the electronics of the instrument Consult your instru j Always run batteries until th in the equipment ro
12. of the telescope eyepiece lens objective lens and removal of parallax e Initialization of the instrument in preparation of use Entering the PPM and reflector offset constants g Placing the instrument in angular measurement mode horizontal and zenith h Placing the instrument in distance measurement mode horizontal vertical and slope 2 Setting Up over a Point This procedure will be practiced in the field according below Be sure the tribrach locking mechanism is A placed on the tripod i a Set the length of the tripod leg sight approximately equal to your chin height A b Spread the tripod legs 1mb or by your best estimate position the tripod apptox over the point with the tripod base plate as horizontal as poss c Firmly plant theffipod leg d Mount the total n to the middle of the tripod base plate using the significantly then your tripod is not stable Repeat step c Loosen the tripod base plate screw Fine level using the three leveling screws j Fine center the instrument over the point translating the instrument on the tripod base plate k Iterate steps f and g until the instrument is fine leveled and fine centered I Tighten the tripod base plate screw Objective lens V ertical circle Lock Vertical tangent screw Horizontal grele Lock Horizontal circle tangent screw Optical plummet lens focus Optical plummet eyepiece Eyepiece focus
13. on B and levelled properly Now the alidade is placed along the line ba and the orientation is done by back sighting At this time it should be remembered that the centering levelling and orientation must be perfect simultaneously vi With the alidade touching b the object P and O are bisected and the rays are drawn Suppose these rays intersect the previous rays at points p and q These points p and g are the required positions of two inaccessible points on drawing sheet Fig P A M a zA CAN s 4 x V x s N 7 f N 7 AJ x 3 3 e V 4 N i 4 P 4 N Z N V AN P 77 N 7 N 4 gt 7 s 7 7 x V x 4 7 z S z Z z 4 I r f 7 4 Z 4 7 Trough Compass Fig Intersection Methoc Expt No 8 Date DETERMINATION OF ELEVATION O F VARIOUS POINTS WITH DUMPY LEVEL a COLLIMATION PLANE METHOD b RISE AND FALL METHOD AIM To determine the Reduced levels of various points INSTRUMENTS REQUIRED Dumpy level and Levelling Staff THEORY TEMPORARY ADJUSTMENTS OF DUMPY LEVEL The Temporary Adjustments Station Adjustments are Setting over the station Centering p Levelling up Elimination of Parallax 1 SETTING OVER THE STATIONCE ERIN a joining any two such as A and B of the leveling foot screws Hold these two foot screws between the thumb and first finger of each hand and turn them uniformly
14. ted he instrument is set up over O It is centered and leveled perfectly ii The lower clamp is kept fixed The upper clamp is loosened and by turning the telescope clockwise Vernier A is set to 0 and the Vernier B to approximately 180 The upper clamp 1s then tightened Now by turning the upper tangent screw the verniers A and B are set to exactly 0 and 180 by looking through the magnifying glass 111 The upper clamp 1s tightly fixed The lower clamp 1s lossened and the telescope 1s directed to the left hand side The ranging rod at A 1s bisected approximately by perfectly focusing the telescope and eliminating parallax The upper clamp 1s tightened and the ranging rod at A is bisected properly Here the initial reading of Vernier A is 0 iv The upper clamp is loosened and the telescope turned anticlockwise to exactly bisect the ranging rod at A Here the initial reading is 30 for the second observation v The lower clamp is tightened The upper is loosened and the telescope t ftned clockwise to exactly bisect the ranging rod at B Let the reading on Vernier A 1 vi The initial reading for the third observation is set to 60 Angl easured Let the final reading on vernier A be 90 which is the accu Accumulated angle 90 Angle AOB _ _ Number of reading 3 vii The face of the instrument is changed and f viii The mean of the observations 1 e fac ef ace right is the actual angle AOB
15. the process at every station vil It is to be noted that first and last stations have only fore bearing and back bearing respectively vil Enter the readings in a tabular form TABULAR FORM FOR CLOSED TRAVERSE S No LINE LENGTH FORE BEARING BACK BEARING REMARKS o Pe 7 CHECK ON CLOSED TRAVERSE The difference between fore bearing and back bea should be 180 if no local attraction exists at either station CHECK ON ANGULAR MEASUREM it Tecno M Right hand de k be measured once on two different days along opposite measurements should tally asurement should also taken a Stadia method The measurements by a line indicating the magnetic meridian North line at A aw the line AB to a suitable scale from the measured distance and bearings iii Draw magnetic meridian at B parallel to the North line which was drawn at A iv From B knowing fore bearing and distance BC draw a line BC V Similarly draw all the remaining lines and complete the closed traverse vi Check the accuracy by comparing the difference between fore bearing and back bearings taken from 1 and Last stations If they differ by 180 the plotting is correct In case of closed traverse there may be a closing error which should be adjusted graphically Bowditch s Rule Expt No 7 a Date PLANE TABLE SURVEYING METHODS a RADIATION METHOD 1 AIM To locate objects from single statio
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