Introduction to Plane Table Surveying in Civil Engineering

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Plane table surveying is a graphical and cost-effective method used for surveying small-scale areas. This method involves simultaneous plotting of the survey while in the field, ensuring accuracy and efficiency. Key principles, instruments, setting up procedures, advantages, disadvantages, and common errors in plane table surveying are discussed. The positioning of the plane table, orientation towards magnetic north, and the use of specific equipment like tripods and alidades are emphasized for accurate results in civil engineering projects.

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SAL INSTITUTE OF TECHNOLOGY AND ENGEENIRING RESEARCH Ahmedabad B.E (3rd Semester)-Civil-Shift 2 December-2014 Group-3 Shah Disha R.(T-13CL247) Gosai Beran M.(T-13CL207) Chavda Hetal N.(T-13CL203) Patel Keval K.(T-13CL223) Patel Tejasvini D.(T-13CL225)

Plane Table Survey Plane Table Survey

Content Plane Table Surveying Principle Instruments setting up the plane table methods of plane tabling Advantages & Disadvantages sources of Errors.

Plane Table Surveying Plane survey plotting are done simultaneously. It is simple It is most suitable for small scale maps. The plan is drawn by the surveyor in the field, while the area to be surveyed is before his eyes. Therefore, there is no possibility of omitting the necessary measurements. Plane Table survey in which the field observations and Table Surveying Surveying is is a a graphical graphical method method of of simple and and cheaper cheaper than than theodolite theodolite survey survey.

Principle Of Plane Table Survey Principle Of Plane Table Survey The means, Principle details The Position of plane table at each station must be identical, i.e. at each survey station the table must be oriented in the direction of magnetic north. The principle means, Principle: : All details should principle of of plane plane tabling tabling is is parallelism parallelism All the pass through the rays rays drawn through the drawn through the survey through various survey station various station. should pass

Principle Of Plane Table Survey Principle Of Plane Table Survey

Equipments and Accessories for Plane Tabling The following instruments are used in plane table surveying. Equipments Plane Table Tripod Alidade Equipments and Accessories for Plane Tabling

Equipments and Accessories for Plane Tabling Accessories Trough Compass Spirit level U-Fork with Plumb bob Water proof cover Drawing paper Pins Drawing accessories Equipments and Accessories for Plane Tabling

Equipments Equipments Plane Table: The drawing board for plane tabling is made from well-seasoned wood with its upper surface exactly plane. It is normally rectangular in shape with size 75 cm x 60 cm It is mounted on a tripod and clamps are provided to fix it in any direction. The table can revolved about its vertical axis and can be clamped in any position, when necessary.

Plane Table

Plane Table Plane Table

Tripod Tripod The plane table is mounted on a tripod The tripod is generally of open frame type, combined rigidity with lightness. The tripod may be made to fold for convenience of transportation. Tripod is provided with three foot screws at its top for leveling of the plane table.

Tripod Tripod

Alidade Alidade The alidade is useful for establishing a line of sight. Two Types of alidade are used. 1. Simple alidade 2. Telescopic alidade

Simple Alidade It is used for ordinary work It is generally consists of a gun metal or wooden rule with two vertical vanes at the ends. The eye-vane is provided with a narrow slit while the object vane is open and carries a horse hair. Both the slits, thus provide a definite line of sight which can be made to pass through the object to be sighted

Simple Alidade Simple Alidade

Simple Alidade Simple Alidade To draw the rays, one of the edge of alidade is beveled and this perfectly smooth working edge is known as the fiducially The fiducially the fiducially edge edge is is graduated distances to to a a scale edge. fiducially edge the plotting graduated to to facilitate scale. facilitate plotting of of distances

Telescopic The telescopic required It essentially consists of a small telescope with a level tube and horizontal It gives higher sights Telescopic Alidade telescopic alidade required to to take Alidade alidade is is used take inclined used when sights. when it it is is inclined sights and graduated axis. . higher accuracy graduated arc arc mounted mounted on on horizontal axis accuracy and and more more range range of of sights. .

Telescopic Alidade Telescopic Alidade

Telescopic Alidade Telescopic Alidade

Accessories Accessories Trough The trough the paper magnetic meridian. When the freely each paper which represents the magnetic Trough Compass trough compass the line paper. . It is used to orient the table to the Compass compass is is required line showing required for magnetic meridian for drawing meridian on drawing on the showing magnetic the freely suspended end, a line is drawn on the drawing suspended needle needle shows shows 0 00 0at at each end magnetic north north.

Trough Compass Trough Compass

Spirit Level Spirit Level A Spirit table The Table board getting the bubble central in both positions. Spirit Level table is is properly Table is is leveled board in in two Level is is used properly level leveled by two positions used for level. by placing positions at at right for ascertaining ascertaining If If the the placing the the level right angles level on angles and on the the

Spirit Level

U U- -Fork With Plumb bob Fork With Plumb bob U U- -fork the table over the point or station occupied by the plane table when the plotted position of that point is already on the sheet. Also, in the beginning for fork with with plumb plumb bob bob is is used used for for centering centering beginning of of the the ground the work, point on work, it it is is used on the used sheet. for transferring transferring the ground point the sheet

U U- -Fork With Plumb Bob Fork With Plumb Bob

Water Proof Cover Water Proof Cover An umbrella is used to protect the drawing paper from rain.

Drawing Paper Drawing Paper Drawing paper is used for plotting the ground details.

Setting Up the Plane table i. Fixing the plane table on the tripod stand ii. Leveling the table iii. Centering the table iv. Marking the North-line v. Orientation 1. Orientation by magnetic needle 2. Orientation by backsighting

Methods Of Plane Tabling 1. Radiation 2. Intersection 3. Traversing 4. Resection Special Methods of Resection I. Compass Method II. Back-ray Method III. Two-point problem IV. Three-point problem

Advantages and Disadvantages of Plane Table Surveying Advantages The plan while the area to be surveyed is before his eyes. Therefore, omitting The surveyor with the actual features of the area. Advantages and Disadvantages of Plane Table Surveying Advantages: : plan is is drawn drawn by by the the surveyor surveyor himself himself Therefore, there omitting the surveyor Can there is is no necessary measurements Can compare no possibility measurements. compare the possibility of of the necessary the plotted plotted work work

Advantages and cheaper Advantages cheaper than It is simple survey It is most suitable No great map subordinate. It is useful not be used. The eliminated simple and than the the theodolite theodolite survey. . suitable for skill is is required and for small required to produce a satisfactory work small scale scale maps maps. . great skill may be entrusted to a useful in in magnetic magnetic areas areas where compass may mistakes mistakes in in writing writing field field books books are are eliminated. .

Advantage Advantage

Disadvantages Disadvantages Disadvantages (Limitations): It is not intended for very accurate work. It is not suitable in monsoon. It is essentially a tropical instrument. Due to heaviness, it is inconvenient to transport. Since there are so many accessories, there is likelihood of them being lost.