Note for Surveying-1 - s-1 By ONKAR PATANGE
- Surveying-1 - s-1
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INTRODUCTION AND CHAIN SURVEYING 1. Define Surveying. What are the fundamental principles of surveying? Surveying is an art of determining the relative positions of various points on, above or below the surface of the earth by means of direct or indirect measurement of distance, direction and elevation. The principles of surveying are: (i). Working from whole to part. (ii). To locate a new station by at least two measurements (angular, linear) from fixed reference points. 2. What is the object or purpose of surveying? The primary object of surveying is to prepare a plan or map to show the relative position of the objects on the surface of the earth. It is also used to determine the areas, volumes and other related quantities. 3. Name the different ways of classification of surveys. a.Primary classification (i). Plane surveying (ii). Geodetic surveying. b. Secondary classification (i). Based on instruments used (ii). Based on methods. (iii). Based on object (iv). Based on nature of the field 4. Differentiate between plane and geodetic surveying. a) Plane surveying 1.The curvature of the earth is neglected. 2.A line joining any two points is considered straight. 3.The triangle formed by any three points is considered as plane triangle. 4.It is done on a area less than 250 Km 2
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b) Geodetic surveying. 1.The curvature of the earth is taken. 2.A line joining any two points is considered as curved line. 3.The triangle formed by any three points is considered as spherical triangle. 4.It is done on a area greater than 250 Km 2 5. 1 2 3 4 5 6 7 Classify surveying based on the equipments. Chain surveying Compass surveying Plane table surveying Theodolite surveying Tacheometric surveying Photogram metric surveying Aerial surveying 6 Explain the constructions of a diagonal scale. For a given short length ( PQ=PR), draw a right angle triangle. Its base( PR) and height (PQ) are equal. A short length is divided into a number of parts by using the principle of similar triangles in which like sides are proportional. Thus, 1-1 represents 1/ 10 PQ 9-9 represents 9/ 10 PQ 7. Define chain surveying. What is the fundamental principle of chain surveying? Chain surveying is the type of surveying in which only linear measurements are made in the field.
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The main principle of chain surveying or chain triangulation is to provide a framework consist of number of well-conditioned triangles or nearly equilateral triangles. It is used to find the area of the field. 8. What is a well-conditioned triangle? What is its specific advantage? A triangle is said to be well- conditioned or well proportioned when it contains no angle smaller than 300 and no angle greater than 1200 . The main principle of chain surveying is chain triangulation. It consists of frame work of triangles. To plot the network of triangles accurately, the triangles must be nearly equal to equilateral or well-conditioned. The distortion due to errors in measurement and plotting should be minimum. 9. What are the operations involved in chain survey? (i). Ranging: The process of locating intermediate points on a straight line between two end points in a straight line. (ii). Chaining: The process of measuring the distance with a chain or tape. (iii). Offsetting: The process of measuring the lateral distance of the object from the survey line to the left or right according to their positions. 10. What are the instruments required for a chain survey? Chain or tape, Arrows, Pegs, Ranging rods, Offset rods, Laths or whites, Plumb bob, Cross staff and Mallet. 11. Write the different types of Chain. (i). Metric chain
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(ii). Non-Metric chain (a).Gunter's chain or Surveyor's chain (b). Engineer's chain (c). Revenue chain (d). Steel band. 1. Differentiate between Gunter's chain and Engineer's Chain Gunter's chain or Surveyor's chain It is 66 feet long and divided in to 100 links. 1link = 0.66 feet Measurements are in miles and furlongs. Engineer's chain It is 100 feet long and divided in to 100 links. 1link = 1 feet Measurements are in feet and decimals 12. What are the instruments used for setting out right angles to a chain line? (i). Cross staff. a. Open cross staff b. French cross staff c. Adjustable cross staff (ii). Optical square. (iii). Prism square (iv). Site square. 13. What are offsets? Classify them. An offset is the lateral distance of an object or ground feature measured from a survey line. The two types of offsets are,
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