Lecture 02 types of surveying

UET TAXILA

1. SURVEYING Surveying is the art of making measurements of relative positions of natural and man-made features on or near the surface of earth and then plotting them to some suitable scale to form a map. They are often used to establish maps and boundaries for ownership, locations, such as building corners or the surface location of subsurface features, or other purposes required by government or civil law, such as property sales. 1

2. Survey is performed to prepare a map of relative positions on surface of the earth. It shows the natural and artificial feature of a country such as towns, villages, roads, railways, etc. They may also include details of different engineering works such as bridge, canal, dam etc. 2 SURVEYING

3. Before commencement of any major engineering project, survey is carried out to determine the location of site and its surrounding. To understand the topography of the site and natural resource availability. Survey is carried out to prepare the cadastral map showing property boundaries. 3 SURVEYING

4. The accuracy and thus reliability of the survey depends not only on the field expertise but also on the surveyor’s understanding of the scientific principles. 4 SCIENCE ? 

5. BRIEF HISTORY The nearly perfect squareness and north-south orientation of the Great Pyramid of Giza , built 2700 BC, affirm the Egyptians' command of surveying. 5

6. BRIEF HISTORY Stonehenge is a prehistoric monument in Wiltshire, England. It consists of a ring of standing stones, with each standing stone around 13 feet (4.0 m) high, 7 feet (2.1 m) wide. A recent reassessment of Stonehenge, (2500 BC) suggests that the monument was set out by prehistoric surveyors using peg and rope geometry. 6

7. OBJECTIVE The main objective of surveying is to form the map of the site. This map should provide following information: 7 Distance between different features on the site. Direction of the features. Difference of level between different features.

8. OBJECTIVE It also involves marking of lines and grades needed for the construction of building, roads, dams and other engineering structures. Surveying has many industrial applications as well like; setting equipment, laying out assembly lines, and so on. 8

9. CLASSIFICATION 2. Geodetic Survey 1. Plane Survey 9

10. CLASSIFICATION 1. Plane Survey 10 ln plane survey curvature of earth is not taken into account. Plane surveys are the most commonly practiced method of surveying and treat the earth as a flat or "plane" surface.

11. CLASSIFICATION 1. Plane Survey 11 Good enough for small-scale surveys in limited areas, the curvature of the earth has no effect on the results, thus the computations and results can be referenced to a plane or flat surface. Calculations for a plane surface are relatively simple, since the surveyor is able to use plane geometry and plane trigonometry.

12. Plane Survey Plane surveys, however, are made on such small areas that the effect of curvature may be neglected. e.g., American surveyors put the limit at 250 km 2 for treating the survey as plane. In large scale mapping, adjustments are made for the curvature of earth. E.g., For highways and Railroads, corrections applied at regular interval of 1 mile to correct for the earth curvature. 12

13. Plane Survey Most of surveys are sufficiently accurate for all but not for the largest areas. Survey of farms, subdivisions, buildings etc in fact most constructed works are plane surveys. 13

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15. Plane Survey It can also be shown that an arc along the earth’s curved surface of 11.5 miles in length is only approximately 0.5 feet longer than the plane or chord distance between its ends. 15 RIGHT TO KNOW…

16. Geodetic Survey In geodetic surveying, also called Trigonometric Surveying. It is necessary to take into account the curvature of the earth. Since shape of the earth is spheroidal, the line connecting any two points on the surface of the earth is curved or an arc of a giant circle. Traditional geodetic survey is of great magnitude like; 16 National Boundaries

17. Geodetic Survey Geodetic surveys are those that are adjusted for the curved shape of the Earth’s surface. Since they allow for earth’s curvature, geodetic surveys can be applied to both small and large areas. 17

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19. The ruling principle of surveying is to work from the whole to a part and not from part to whole. According to this principle, it is always desirable to carryout survey work from whole to part. This means, when an area is to be surveyed, first a system of control points is to be established covering the whole area with very high precision. Then minor details are located by less precise methods. 19 Basic Principle of Surveying

20. Basic Principle of Surveying The ruling principle of surveying is to work from the whole to a part and not from part to whole. First, control points are established in the area to be surveyed and this can be done through a network of triangles or traversing. Control points for the “primary network" are provided with the help of instruments of highest precision and by adopting well-established methods of observation. The underlying idea is to minimize the accumulation of error and to localize the error. If the survey is made to expand outward from the central points, the minor errors will become so magnified as to become uncontrollable at the end. 20

21. SURVEYING LECTURE 02 21

22. Classification of Survey 22

23. Classification of Survey Classification Based on Instrument 23

24. Classification Based on Methods 24 Classification of Survey

25. Classification Based on Methods 25 Classification of Survey

26. 26 Classification of Survey Classification Based on Objective

27. 27 Classification of Survey Classification Based on Objective

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29. TYPES OF SURVEY This section is devoted to a brief description of various types of surveys. 29 Land surveys are the oldest type of survey and have been performed since earliest recorded history. They are normally plane surveys made for locating property lines, subdividing land into smaller parts, determining land areas, and any other information involving the transfer of land from one owner to another. These surveys are also called property surveys, boundary surveys or cadastral surveys.

30. TYPES OF SURVEY 30 Topographic surveys: By topography is meant the shape or configuration of the earth’s surface. Topographic surveying is the process of determining the positions, both in plan and elevation, of the natural and artificial features of a region, and delineating them by means of conventional symbols upon a map called a topographic map. The distinguishing feature of a topographic survey is the location and sketching of contours. A topographic map shows, hills and valleys, streams, rivers, lakes, trees, etc. Also the artificial features, such as roads, railways, canals, houses etc

31. Topographic Survey 31

32. TYPES OF SURVEY 32 Route surveys: It involve the determination of the location of natural and artificial objects along a proposed route for a highway, railroad, canal, pipeline, power line, or other utility. They may further involve the location or staking out the facility and the calculation of earthwork quantities.

33. TYPES OF SURVEY 33 City or Municipal surveys: are made within a municipality for the purpose of laying out streets, planning sewer systems, preparing maps and so on. When the term is used, it usually brings to minds topographic surveys in or near a city for the purpose of planning urban expansions or improvements.

34. Route surveys 34

35. TYPES OF SURVEY Construction surveys are made for purpose of locating structures and providing required elevation points during their construction. They are needed to control every type of construction project. 35

36. TYPES OF SURVEY 36 Hydrographic surveys pertain to lakes, streams and other bodies of water. Shorelines are chartered, shapes of areas beneath water surfaces are determined, water flow of streams is estimated, and other information needed relative to navigation, flood control and development of water resources is obtained. These surveys are usually made by a governmental agency.

37. Hydrographic Survey 37 Shorelines are chartered

38. TYPES OF SURVEY Marine surveys are like hydrographic surveys, but they are thought to cover a broader area. They include the science of navigation, marine features and water depth etc on hydrographic maps and charts. 38

39. TYPES OF SURVEY 39 Mine surveys are made to obtain the relative positions and elevations of underground shafts, geological formations, and so on. Shafts (The Qanat System) Aerial View of Qanat

40. TYPES OF SURVEY Forestry and Geological surveys are much more common than the average layperson realizes. Foresters use surveying for boundary , locations, timber cruising, topography, and so on. Similarly, surveying has much application in the preparation of geological maps. 40 Photogrammetric surveys are those in which photographs (generally aerial) are used in conjunction with limited ground surveys (used to establish or locate certain control points visible from the air).

41. Forestry Survey 41

42. TYPES OF SURVEY As Built survey is similar to preliminary survey with a difference of that it has been constructed to provide a final record of the construction and to check the construction has proceeded according to the design plan. Also called in-built survey. 42

43. TYPES OF SURVEY 43 Control surveys are reference surveys. For a particular control survey a number of points are established and their horizontal and vertical positions very accurately determined. These points are called Bench Marks .

44. Land Surveying Techniques Land surveys are used to determine land boundaries for a variety of reasons, including the selling or buying a property, putting up a fence or larger scale projects such as building roads and highways. While there are many different land surveying techniques, there are five fundamental ones that are used the most often. These five techniques can be used alone or, most often, in a combination of some form or another. 44

45. Triangulation  – This technique uses a series of fixed points or stations in the area to be measured. These stations are connected as triangles, joining and overlapping each other. From these points, angles are measured. This is the most commonly used of the land surveying techniques and is also the most efficient in that it minimizes the number of different measurements that are needed. 45 Land Surveying Techniques

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47. Trilateration  – Using the same principles as described in the triangulation method of land surveying techniques, trilateration adds electronic distance measuring equipment. This allows for faster and easier mapping of uneven and rough terrain. 47 Land Surveying Techniques

48. Leveling  – This technique is used to determine land elevations. It begins with a fixed point such as a metal pole and uses a leveling instrument to move up and down an area, determining height at specific points along the way. Each one of these points provides part of the calculation, which is determined using trigonometry methods. The most common use for this type of land surveying technique is in determining information for elevation maps. 48 Land Surveying Techniques

49. Leveling 49

50. Traverse  – The method in which a series of lines with predetermined and measured distances and lengths are used to connect together at various points in determined location. These traverse lines can be open or closed and can be easily moved around uneven terrain or obstacles that are in the way. This technique is most often used in the surveying for new roads, railroads and other such linear projects. 50 Land Surveying Techniques

51. Traverse 51

52. Radiation  – Most commonly used along with a plane table, this land surveying technique is often used in conjunction with triangulation and traverse methods of measurement. This method takes a fixed position above a ground location in which various points are taken along the boundary line then drawn out on paper. Once drawn out, the distance is measured and converted to the necessary scale on the survey sheets. 52 Land Surveying Techniques

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54. Accuracy and Precision Accuracy: It is the relationship between the value of a measurement and the “true” or theoretically correct value of the dimension being measured. Precision: It describes the refinement of the measuring process and the ability to repeat the same measurement with consistently small variation in different conditions. 54

55. Accuracy and Precision 55 High Accuracy Low Accuracy High Precision Low Precision