![Fig: 2 – Plane Alidade
Telescopic Alidade:
It consists of a telescope mounted on a column fixed to the ruler [Fig. 3]. The line of sight
through the telescope is kept parallel to the bevelled edge of the ruler. The telescope is
provided with a level tube and vertical graduation arc. If horizontal sight is required bubbles
in the level tube are kept at the centre.
If inclined sights are required vertical graduation helps in noting the inclination of the line of
sight. By providing a telescope the range and the accuracy of line of sight is increased.
Fig. 3: Telescopic alidade](https://image.slidesharecdn.com/asump-221217112101-e721cdcc/85/ASU-MP-docx-8-320.jpg)
ASU MP.docx
- 1. Y.B. PATIL POLYTECHNIC SECTOR NO. 29, AKURDI, PUNE -411044, INDIA HRISHIKESH TARANGE – Y-2070-1901340102 ATHARVA PATIL – Y-2075-1901340081 YOGESH YELAVI -Y-2083-1901340103 PRATHAMESH ROKDE – Y-2031-1901340079 AVINASH SAKHERE – Y-2058 -1901340080 DAVENDRA SUTHAR – Y-2077-1901340104 This is to certify ;has satisfactorily carried out and completed the project work entitled methods of plane table surveying This work is being submitted for the award of Diploma in civil Engineering partial fulfillment of prescribed syllabus of M.S.B.T.E Mumbai for academic Year 2020 MR.AMIT GHONGADE MR,ABHIJEET PATIL GUIDE HOD CIVIL DEPARTMENT PRINCIPLE PROF.A.S KONDEKAR Micro project proposal Topic-methods of plane table surveying
- 2. 1.Aims/benefits of micro project: To get knowledge about methods of plane table surveying its objective its component use in civil engineering introduction & knowledge of methods of plane table surveying 2 Course outcome addressed. 1 To learn about methods of plane table surveying 2. To learn about component & it use 3. To learn about their advantage & disadvantage 3 Action plan Sr. No. Details of activity Planned Start date Planed Finished date Name of responsible team member 1) Collection of information. 20/06/2020 20/06/2020 HRISHIKESH TARANGE – Y1171 ATHARVA PATIL – Y1154 2) Working of Microsoft Word. 20/06/2020 23/06/2020 YOGESH YELAVI – Y1177 PRATHAMESH ROKDE – Y1161 3) Taking Prints of the project made in Microsoft Word & Microsoft word & binding it 22/06/2020 22/06/2020 AVINASH SAKHERE – Y1162 DAVENDRA SUTAR – Y1170 5 Resource Required Sr.no Name of resource /materials specification Qty Remark 1 Internet and reference book Collect information 1
- 3. 2 laptop Working on Microsoft word 1 Name of team member with roll no HRISHIKESH TARANGE – Y2070 ATHARVA PATIL – Y2075 YOGESH YELAVI – Y2083 PRATHAMESH ROKDE – Y2031 AVINASH SAKHERE – Y2058 DAVENDRA SUTAR – Y2077 Micro project evaluation sheet Name of student HRISHIKESH TARANGE – Y2070 ATHARVA PATIL – Y2075
- 4. YOGESH YELAVI – Y2083 PRATHAMESH ROKDE – Y2031 AVINASH SAKHERE – Y2058 DAVENDRA SUTAR – Y2077 Name of programme: micro project on the methods of plane table surveying Semester:1st Course title: Advance surveying Title of micro project :methods of plane table surveying Course outcome achieved 1 To learn about methods of plane table surveying 2. To learn about component & it use 3. To learn about their advantage & disadvantage Sr no Characteristic to be assessed Poor (mark 1-3) Average (mark 4-5) Good (mark 6-8) Excellent (mark 9-10) Sub total (A)PROCESS AND PRODUCT ASSESSMENT CONVERT ABOVE TOTAL MARK OUT OF 6 MARK 1 Relevance to the course 2 Literature review/information 3 Completion of the target as per project proposal 4 Analysis of date and representation 5 Quality of prototype/model 6 Report preparation (B)INDIVIDUAL PRESENTATION/VIVA CONVERT ABOVE MARK OUT OF 4 MARKS 7 Presentation 8 viva NAME ROLL NO (A) PROCESS AND PRODUCT (B) INDIVIDUAL PRESENTATIO TOTAL MARK (10 MARK)
- 5. ASSESSMENT (6MARK) N/ VIVA (4 MARK) HRISHIKESH TARANGE Y-1171 ATHARVA PATIL Y-1154 YOGESH YELAVI Y-1177 PRATHAMESH ROKDE Y-1161 AVINASH SAKHERE Y-1162 DAVENDRA SUTAR Y-1170 COMMENTS/SUGGESTION ABOUT TEAMWORK/LEADERSHIP/INTERPERSONAL COMMUNICATION ( IF ANY) NAME AND DESIGNATION OF TEACHER ………………………………………………… DATED SIGNATURE……………………………… What is Plane Table Surveying? Plane table surveying is the fastest method of surveying. In this type of surveying plotting of the plan and field observations can be done simultaneously. In case of plane table surveying Geometrical conditions of site are manuscript in the map sheet using plane table and alidade after that topographic details are arranged on the map. Equipment Used in Plane Table Survey
- 6. General equipment used for conducting plane table survey are ● Plane table ● Alidade for sighting (telescopic or simple) ● Plumb bob and plumb fork ● Compass ● Spirit level ● Chain ● Ranging rods ● Tripod ● Drawing sheet and drawing tools ● Paper clips or screwsIn a plane table surveying a table top, similar to a drawing board fitted onto a tripod is the main instrument. A drawing sheet is fixed on to the table top, the observations are made to the objects, distances are scaled down and the objects are plotted in the field itself. Since the plotting is made in the field itself, there is no chance of omitting any necessary measurement in this surveying. However the accuracy achieved in this type of surveying is less. Hence this type of surveying is used for filling up details between the survey stations previously fixed by other methods. The most commonly used plane table is shown in Fig. 1. It consists of a well seasoned wooden table top mounted on a tripod. The table top can rotate about the vertical axis freely. Whenever necessary the table can be clamped in the desired orientation. The table can be levelled by adjusting tripod legs. Fig: Plane table with tripod stand
- 7. Equipments for Plane Table Surveying The following accessories are required to carry out plane table survey: 1. Alidade 2. Plumbing fork with plumb bob 3. Spirit level 4. Trough compass 5. Drawing sheets and accessories for drawing. 1. Alidade It is a straight edge ruler having some form of sighting device. One edge of the ruler is bevelled and is graduated. Always this edge is used for drawing line of sight. Depending on the type of line of sight there are two types of alidade: (a) Plain alidade (b) Telescopic alidade Plain Alidade: Figure 2 shows a typical plain alidade. A sight vane is provided at each end of the ruler. The vane with narrow slit serves as eye vane and the other with wide slit and having a thin wire at its centre serves as object vane. The two vanes are provided with hinges at the ends of the ruler so that when not in use they can be folded on the ruler. Plain alidade is not suitable in surveying hilly areas as the inclination of line of sight in this case is limited.
- 8. Fig: 2 – Plane Alidade Telescopic Alidade: It consists of a telescope mounted on a column fixed to the ruler [Fig. 3]. The line of sight through the telescope is kept parallel to the bevelled edge of the ruler. The telescope is provided with a level tube and vertical graduation arc. If horizontal sight is required bubbles in the level tube are kept at the centre. If inclined sights are required vertical graduation helps in noting the inclination of the line of sight. By providing a telescope the range and the accuracy of line of sight is increased. Fig. 3: Telescopic alidade
- 9. 2. Plumbing Fork and Plumb Bob Figure 4 shows a typical plumbing fork with a plum bob. Plumbing fork is a U-shaped metal frame with an upper horizontal arm and a lower inclined arm. The upper arm is provided with a pointer at the end while the lower arm is provided with a hook to suspend plumb bob. When the plumbing fork is kept on the plane table the vertical line (line of plumb bob) passes through the pointed edge of the upper arm. The plumb bob helps in transferring the ground point to the drawing sheet and vice versa also. Fig. 4: Plumbing fork and plumb bob 3. Spirit Level A flat based spirit level is used to level the plane table during surveying (Fig.5). To get perfect level, spirit level should show the central position for bubble tube when checked with its positions in any two mutually perpendicular directions.
- 10. Fig. 5: Spirit level 4. Trough Compass It consists of a 80 to 150 mm long and 30 mm wide box carrying a freely suspended needle at its centre (Ref. Fig. 6). At the ends of the needle graduations are marked on the box to indicate zero to five degrees on either side of the centre. The box is provided with a glass top to prevent oscillation of the needle by wind. When the needle is centred (reading 0–0), the line of needle is parallel to the edge of the box. Hence marking on the edges in this state indicates magnetic north–south direction. Fig. 6: Trough compass 5. Drawing Sheet and Accessories for Drawing A good quality, seasoned drawing sheet should be used for plane table surveying. The drawing sheet may be rolled when not in use, but should never be folded. For important works fibre glass sheets or paper backed with thin aluminium sheets are used. Clips clamps, adhesive tapes may be used for fixing drawing sheets to the plane table. Sharp hard pencil, good quality eraser, pencil cutter and sandpaper to keep pencil point sharp are other accessories required for the drawing work. If necessary, a plastic sheet should be carried to cover the drawing sheet from rain and dust.
- 11. Plane table survey equipment is arranged in 4 steps as follows Fixing of Plane Table Fix the plane table to the tripod stand. Arrange the drawing sheet on the plane table using paper clips or thumb screws. The sheet should be in one position from first to last. Leveling of Plane Table Plane table should be leveled using spirit level. For small works, eye estimation can be ok. Centering of Plane Table The table should be centered by using a plumbing fork. By which we can arrange the plotted point exactly over the ground point. Orientation of Plane Table Whenever we are using more than one instrument station, orientation is essential. It can be done by using compass or back sighting. In this case, the plane table is rotated such that plotted lines in the drawing sheet are parallel to corresponding lines on the ground. Methods of Plane Table Surveying Generally there are four methods available to perform plane table surveying. They are 1. Radiation
- 12. 2. Intersection 3. Traversing 4. Resection Radiation In this method, the plane table is located at one point “o” as shown in fig. and performs the whole from that point. From point O, sight the points A,B,C,D and E using alidade, locate and plot the points as a,b,c,d and e in the drawing sheet. Intersection In this method we can locate the point by plotting two rays from two known stations. As shown in figure, P and Q are the known stations. First the equipment is placed on P and plot the lines by sighting the stations A, B and Q. Then shift the equipment to station Q and plot the lines by sighting stations A, B and P. Finally, the intersection of A and B rays is the required location of the point of intersection.
- 13. Traversing Traversing is the connection of a series of straight lines. In case of traversing, the plane table is located at one point for suppose A as shown below. From that point sight towards B and measure the distance AB. Then shift the plane table to point B and sight towards A and measure BA. Average distances of AB and Ba are plotted to scale in the drawing sheet. Then Sight the point C from B and measure BC and repeat the same procedure until the last point. Conduct some checks at some points. Finally traverse lines are plotted on the drawing sheet. Resection
- 14. Resection is a method of plane table surveying in which the location of the plane table is unknown and it is determined by sighting it to known points or plotted points. It is also called a method of orientation and it can be conducted by two field conditions as follows. ● The three-point problem ● The two-point problem The Three Point Problem In this condition, three points and their positions in the field are known. Plane table is placed at an apposition from where all the three points are visible. So, by sighting those three points we can locate the point where equipment is located. This can be achieved by many methods as follows. ● Tracing method ● Lehmann method ● Analytical methods ● Graphical method Tracing Method in Plane Table Surveying In tracing method, the plane table is located at a point from where three points are visible. The table is oriented with respect to the plotted lines of those three points. Place the tracing paper on the drawing sheet and again sight the three points and plot the radiating lines. The tracing paper is then moved above the drawing sheet until the three radiating lines pass through corresponding points previously plotted on the map. Finally, the position of the plane table is marked.
- 15. Lehmann Method In this method, the Plane table is located at a point P and sights the station A, B and C and plot the rays Aa, Bb, and Cc. The rays form a small triangle which is called a triangle of error. Another point P1 is chosen to reduce the error and sight the point A from P1 similarly to B and C. Which will give another triangle of error. Repeat this procedure until error becomes zero. Analytical Methods There are many analytical methods developed in three-point problem conditions. In this method, from station P A, B and C are sighted and note the values of angles and lengths. From these values determine the position of unknown points by using analytical formulae. Graphical Method In graphical method also, angles and lengths are determined and represented on a graph and determines the location of the plane table. The Two-Point Problem In the two-point problem, two points are sighted from another point corresponding to the points given in the plane table sheet. Here two cases are to be discussed. Case 1: when the points can be occupied by the plane table As shown in fig. A and B are the two points corresponding to the points a and b. Now, the plane table is located at B and oriented by sighting A. Sight C from B and bx is plotted on the
- 16. sheet. Then shift the plane table to C, oriented by backsighting B along xb. Then alidade is placed over a and sight station A, then line Aa cuts the line bx at somewhere which is located as point c at station C. Case2: When the plane table cannot occupy the controlling stations In this case, an auxiliary point D is considered nearer to C. Locate the plane table at D according to the line ab parallel to AB. Then sight the station A and B corresponding to a and b. the rays drawn are intersected at some point which is marked as d. Then sight towards C by placing a alidade at d. mark the distance Dc as c1. Shift the table to C and backsight to D with reference to c1. Then sight A corresponding to a, the ray drawn, intersects the previously drawn ray from D in c2. From c2 sight B draws a ray which intersects db and marks the intersection as b1. The table is oriented till ab comes in line with P. From P sight and draw rays Aa and Ba. The intersection of these two rays will give the Location of Point C.