Instruments used in surveying

Civil engineering

1. Lect#4 Linear and angular Measurement By. M.Z jamali

2. Linear measurement Measurement in which horizontal or vertical distance between two points is measured is called linear measurement.

3. Methods of Linear measurement Pacing (earlier age) Pedometer Passometer Permbulator Odometer Chain Tape

4. Pacing/stepping For rough and speedy work , distances are measured by pacing., i.e by counting numbers of steps taken by a man from one point to other. A walking space of man is considered 2.5ft or 80cm. This is earlier age method and now days it is generally used in reconnaissance survey.

5. Passometer Passometer  is a pocket instrument which count the number of paces taken by a person carrying it. It automatically records the number of paces. Its mechanism is being operated by the motion of the body. It should be held vertically in pocket.

6. Pedometer Pedometer  The device which count steps and measure the distance automatically is known as pedometer. It is similar to passometer but difference is that passometer count the number of paces whereas pedometer records the distance. It is adjusted according to the length of the pace of the person carrying it.

7. Perambulator

8. Perambulator Perambulator The instrument provided with single wheel with forks and handle to measure the distance between two points is known as perambulator. The instrument is wheeled along the line the length of which is desired. The distance traverse is automatically registered on the dials.

9. Odometer Odometer The device which attached with the wheel of any vehicle and records the number of revolutions of the wheel is known as odometer. The number of revolutions multiplied by the circumference of the wheel and records the distance.

10. Chain

11. Chain Metric chain Günter’s Chain Revenue Chain Engineers chain For taking readings chain are provided tallies after 10-15 links. By counting theses tallies distance can be determined. For Ordinary work (less Precision) Chain is used.

12. Metric chain These chains are made in lengths of 20 and 30 meters. 20 m chain is divided in 100links and 30 m chain in 150 liks . Length of each link is 0.2 m in both chains. To facilitate reading of measurement tallies are provided in a 20 m chain after 10 links(2 m) and after 25 links(5m) in 30 m chain. Suitable for fairly level ground.

13. c. Günter’s Chain: It is 66 ft long and is divided into 100 links. Each link is 0.66 ft long. It is very convenient for measuring distance in miles and furlongs. Also for measuring area and when the units of area is an acre. Revenue Chain: It is commonly used for measuring fields in cadastral survey. It is 33 ft long and divided into 16 links. Each link is 2.0625 ft long

14. . Engineer’s chain: It is 100 ft long and it is divided into 100 links. Each link is 1 ft in a length. Used in all Engineering surveys.

15. Engineer Chain ’

16. Revenue Chain

17. Tape

18. Cloth tape It is 15mm wide and is available in length of 10m and 15m. This is generally used in measuring offset and ordinary works.

19. Invar tape: Made of steel 64% and nickel 36%, available in size 30m, 50m, and 100 m. having lower co-efficient of expansion 0.00000012 per degree Celsius. Used for high degree of precision required for base measurements.

20. Metallic Tape More Durable Available in lengths of 15,20, and 30m. Used for all survey work. Steel tape . Available in length10, 15, 20, 30 and 50 meters. For Great Accuracy Steel Tape is used

21. Angular Measurement. The measurement in which angle between two lines and direction of two lines is measured is called angular measurement.

22. Instrument used in Angular Measurement Compass. Clinometers T-Square

23. Clinometer An instrument used for measuring the angle or elevation of slopes

24. Clinometer

25. Compass A compass is a small instrument essentially consisting of a graduated circle, and a line of sight. The compass can not measures angle between two lines directly but can measure angle of a line with reference to magnetic meridian at the instrument station point is called magnetic bearing of a line.

26. Set Square Used to measure only 90 degree angle

27. Modern Techniques/ instrument EDM ( Electronic Distance Machine) Tacheometer Level Machine Theodolite Total Station

28. EDM. Electronic distance measuring instrument is a surveying instrument for measuring horizontal distance electronically between two points.  This is mainly done by chaining or taping. It is a rapid method

29. Tacheometer

30. Tacheometer Tacheometer by which the positions, both horizontal and vertical, of points on the earth's surface relatively to one another are determined without using a chain or tape or a separate leveling instrument. The ordinary methods of surveying with a Theodolite, chain, and leveling instrument are fairly satisfactory when the ground is pretty clear of obstructions and not very precipitous, but it becomes extremely difficult when the ground is much covered with bush, or broken up by ravines

31. Level Machine

32. Level Machine A  dumpy level/   automatic level  is an optical instrument used to establish or verify points in the same horizontal plane. It is used in surveying and building with a vertical staff to measure height differences and to transfer, measure and set heights.

33. Theodolite

34. Theodolite Theodolite is an instrument used in surveying to measure horizontal and vertical angles. The line of sight of Theodolite can be rotated through 180 o  in vertical plane about its horizontal axis. Theodolite which can be rotated through 180 o  in vertical plane about its horizontal axis is called Transit Theodolite and Non-Transit if rotation is not possible

35. Total Station :-

36. Total Station :- A total station is an electronic/optical instrument used in modern surveying Total station  is an   equipment combination of Electromagnetic Distance Measuring Instrument and electronic Theodolite. It is also integrated with microprocessor, electronic data collector and storage system. The instrument can be used to measure horizontal and vertical angles as well as horizontal, vertical and sloping distance of object to the instrument.

37. Prisim

38. Ranging Rod

39. Staff rod