DOWNLOAD PDF PLANE AND GEODETIC SURVEYING FOR ENGINEERS

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1 Chapter 1 : Difference Between Plane Surveying and Geodetic Surveying Geodetic surveying. Effect of the curvature of the earth surface is ignored. The earth surface is assumed to be plane, i.e. two dimensional. Involves smaller areas less than about km 2. Surveying is the art of taking measurement which will determine the relative positions of various points on the surface of the earth. By Land Survey, any portion of earth surface, it may be represented on a plan to a convenient and suitable scale: The various natural and artificial features may be shown in their correct horizontal and vertical positions. Generally, The term Surveying is limited to operations concerned with the representation of ground features in the plan. Whereas the determination of their relative heights is termed as Leveling. The results of Leveling are shown either in a vertical section or a plane, using certain conventions. Therefore, the primary aim of any land survey is the preparation of a plan showing all the features. A Plan may be defined as a projection of the ground and the features upon it on a horizontal plan, the linear and angular measurements are drawn only on horizontal dimensions. The vertical distance may be correctly shown by vertical section or sections. So I hope that now you will be able to Define Survey. Plan Survey and Geodetic Survey. As we all know that the surface of the earth is not plane but spherical. Therefore, the line connecting any two points on the surface of the earth is not a straight line but a curve, and it may be taken as an Arc of a Circle. In surveying of small areas, the curvature of the earth is negligible and, therefore, for all practical purposes, the surface of the earth enclosed between the surveying lines may be assumed as a plane. The surveying conducted with the above assumption is called Plane Survey. Or the surveying in which the curvature of the earth is not taken into account is called Plan Survey. This type of land survey in which the curvature of the earth is taken into account is termed as Geodetic Survey. A definite limit cannot be set for the area up to which surveying may be treated as a plane, as the degree of accuracy required is the main factor. It may be of interest to note that the difference in length between any two points treating the surface of the earth as a plane and as a part of a sphere is only 0. Scope and Use of Surveying. In engineering, geographical, geological, military, etc. Though Plane Surveys may be conveniently used up to areas of Kilometer Square. It may be used for large areas if the accuracy of the work is not too much important. Geodetic Surveys are employed for larger areas and for the determination of accurate positions of widely distant points on the surface of the earth which ultimately form control points for other types of surveying to be conducted in between these points. These type Land surveys are specially performed for the surveying of a country, big cities, etc. Page 1

2 Chapter 2 : Plane and Geodetic Surveying - CRC Press Book Plane surveys are the most commonly practised method of surveying and treat the earth as a flat or "plane" surface. 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. ReadCivil 0 Comments Geodetic surveying, Plane surveying, Principles of surveying, Surveying I know, you are searching in google for the various types of land survey methods. Yes, I am here to give you a brief and simple description for all your doubts in surveying. Surveying is the technique of determining the relative position of different points on, above or beneath the surface of the earth by means of direct or indirect measurements and finally representing them on a sheet of paper known as plan or map. Then they are prepared into any suitable scale. The two types of land survey are described below. In plane surveying, all triangles made by survey lines are plane triangles. All survey lines in plane land survey methods are assumed as straight lines and all plumb lines are assumed as parallel lines. Plane surveying is done of area less than km sq. In geodetic surveying, the surface of the earth is taken as its actual shape not like plane surface as we had done in plane surveying. In geodetic surveying, most of the measurements are taken as angular measurements. This is one the major difference between plane surveying and geodetic surveying. Types of land survey methods based on the nature of field survey 1. Topographic surveying This survey is done by measuring the vertical and horizontal distance of the field. These measurements to determine the natural features of a country such as river, streams, lakes, woods etc, 2. City Surveying They are made for the construction of streets, water supply system, and sewers. Cadastral Surveys Cadastral survey is done for fixing the property line, land area calculation and survey during the transfer of property from one owner to another. Marine or hydrographic survey It deals with bodies of water for purpose of navigation, water supply, harbour works or for the determination of mean sea level. Engineering survey Engineering land survey is to do for the determination of sufficient data for the engineering works such as roads and reservoirs. Military survey This is used for determining points which have strategic importance 3. Mine survey This is used for exploring mineral wealth Types of land survey methods based on the instrument Chain survey. Page 2

3 Chapter 3 : Geodesy - Wikipedia Geodetic surveying is a process of surveying by considering the curvature or spherical shape of the earth. The exact positions of points obtained on plane surveying are given by geodetic. Difference Between Plane Surveying and Geodetic Surveying. Geoid The geoid is essentially the figure of the Earth abstracted from its topographical features. It is an idealized equilibrium surface of sea water, the mean sea level surface in the absence of currents and air pressure variations, and continued under the continental masses. The geoid, unlike the reference ellipsoid, is irregular and too complicated to serve as the computational surface on which to solve geometrical problems like point positioning. The geometrical separation between the geoid and the reference ellipsoid is called the geoidal undulation. A reference ellipsoid, customarily chosen to be the same size volume as the geoid, is described by its semi-major axis equatorial radius a and flattening f. The mechanical ellipticity of the Earth dynamical flattening, symbol J2 can be determined to high precision by observation of satellite orbit perturbations. Its relationship with the geometrical flattening is indirect. The relationship depends on the internal density distribution, or, in simplest terms, the degree of central concentration of mass. It is essentially the basis for geodetic positioning by the Global Positioning System GPS and is thus also in widespread use outside the geodetic community. The geoid is "realizable", meaning it can be consistently located on the Earth by suitable simple measurements from physical objects like a tide gauge. The geoid can therefore be considered a real surface. The reference ellipsoid, however, has many possible instantiations and is not readily realizable, therefore it is an abstract surface. The third primary surface of geodetic interestâ the topographic surface of the Earthâ is a realizable surface. Coordinate systems in space[ edit ] See also: Geodetic system The locations of points in three-dimensional space are most conveniently described by three cartesian or rectangular coordinates, X, Y and Z. Since the advent of satellite positioning, such coordinate systems are typically geocentric: Prior to the era of satellite geodesy, the coordinate systems associated with a geodetic datum attempted to be geocentric, but their origins differed from the geocenter by hundreds of meters, due to regional deviations in the direction of the plumbline vertical. It is only because GPS satellites orbit about the geocenter, that this point becomes naturally the origin of a coordinate system defined by satellite geodetic means, as the satellite positions in space are themselves computed in such a system. Geocentric coordinate systems used in geodesy can be divided naturally into two classes: Inertial reference systems, where the coordinate axes retain their orientation relative to the fixed stars, or equivalently, to the rotation axes of ideal gyroscopes ; the X-axis points to the vernal equinox Co-rotating, also ECEF "Earth Centred, Earth Fixed", where the axes are attached to the solid body of the Earth. A more accurate description also takes polar motion into account, a phenomenon closely monitored by geodesists. Coordinate systems in the plane[ edit ] A Munich archive with lithography plates of maps of Bavaria In surveying and mapping, important fields of application of geodesy, two general types of coordinate systems are used in the plane: It is geodetic practiceâ contrary to the mathematical conventionâ to let the x-axis point to the north and the y-axis to the east. More formally, such coordinates can be obtained from three-dimensional coordinates using the artifice of a map projection. It is not possible to map the curved surface of the Earth onto a flat map surface without deformation. The compromise most often chosenâ called a conformal projection â preserves angles and length ratios, so that small circles are mapped as small circles and small squares as squares. Within the map plane, we have rectangular coordinates x and y. In this case the north direction used for reference is the map north, not the local north. The difference between the two is called meridian convergence. It is easy enough to "translate" between polar and rectangular coordinates in the plane: Page 3

4 Chapter 4 : What is Land Survey Define Survey, Plane & Geodetic Surveying. engineering surveyor all the necessary theoretical knowledge to set up, manage and use such networks, for the construction and monitoring of large or small engineering works. The tools of the engineering surveyor have changed significantly in recent years. Hardware[ edit ] Surveying equipment. Clockwise from upper left: Most instruments screw onto a tripod when in use. Tape measures are often used for measurement of smaller distances. The theodolite is an instrument for the measurement of angles. It uses two separate circles, protractors or alidades to measure angles in the horizontal and the vertical plane. A telescope mounted on trunnions is aligned vertically with the target object. The whole upper section rotates for horizontal alignment. The vertical circle measures the angle that the telescope makes against the vertical, known as the zenith angle. The horizontal circle uses an upper and lower plate. When beginning the survey, the surveyor points the instrument in a known direction bearing, and clamps the lower plate in place. The instrument can then rotate to measure the bearing to other objects. If no bearing is known or direct angle measurement is wanted, the instrument can be set to zero during the initial sight. It will then read the angle between the initial object, the theodolite itself, and the item that the telescope aligns with. The gyrotheodolite is a form of theodolite that uses a gyroscope to orient itself in the absence of reference marks. It is used in underground applications. The total station is a development of the theodolite with an electronic distance measurement device EDM. A total station can be used for leveling when set to the horizontal plane. Since their introduction, total stations have shifted from optical-mechanical to fully electronic devices. They are fully robotic, and can even point data to a remote computer and connect to satellite positioning systems, such as Global Positioning System. Static GPS uses two receivers placed in position for a considerable length of time. The long span of time lets the receiver compare measurements as the satellites orbit. The changes as the satellites orbit also provide the measurement network with well conditioned geometry. RTK surveying uses one static antenna and one roving antenna. The static antenna tracks changes in the satellite positions and atmospheric conditions. The surveyor uses the roving antenna to measure the points needed for the survey. The two antennas use a radio link that allows the static antenna to send corrections to the roving antenna. The roving antenna then applies those corrections to the GPS signals it is receiving to calculate its own position. RTK surveying covers smaller distances than static methods. This is because divergent conditions further away from the base reduce accuracy. Surveying instruments have characteristics that make them suitable for certain uses. Theodolites and levels are often used by constructors rather than surveyors in first world countries. The constructor can perform simple survey tasks using a relatively cheap instrument. Total stations are workhorses for many professional surveyors because they are versatile and reliable in all conditions. The productivity improvements from a GPS on large scale surveys makes them popular for major infrastructure or data gathering projects. One-person robotic-guided total stations allow surveyors to measure without extra workers to aim the telescope or record data. A fast but expensive way to measure large areas is with a helicopter, using a GPS to record the location of the helicopter and a laser scanner to measure the ground. Software[ edit ] Land surveyors, construction professionals and civil engineers using total station, GPS, 3D scanners and other collector data use Land Surveying Software to increase efficiency, accuracy and productivity. Land Surveying Software is a staple of contemporary land surveying. The factors that can affect the accuracy of their observations are also measured. They then use this data to create vectors, bearings, coordinates, elevations, areas, volumes, plans and maps. Measurements are often split into horizontal and vertical components to simplify calculation. GPS and astronomic measurements also need measurement of a time component. Distance measurement[ edit ] Example of modern equipment for surveying Field-Map technology: GPS, laser rangefinder and field computer allows surveying as well as cartography creation of map in real-time and field data collection. Before EDM devices, distances were measured using a variety of means. To measure horizontal distances, these chains or tapes were pulled taut to reduce sagging and slack. The distance had to be adjusted for heat expansion. Attempts to hold the measuring instrument level would also be made. When measuring up a slope, the surveyor might have to "break" break Page 4

5 chain the measurement- use an increment less than the total length of the chain. Perambulators, or measuring wheels, were used to measure longer distances but not to a high level of accuracy. Tacheometry is the science of measuring distances by measuring the angle between two ends of an object with a known size. It was sometimes used before to the invention of EDM where rough ground made chain measurement impractical. Angle measurement[ edit ] Historically, horizontal angles were measured by using a compass to provide a magnetic bearing or azimuth. Later, more precise scribed discs improved angular resolution. Mounting telescopes with reticles atop the disc allowed more precise sighting see theodolite. Levels and calibrated circles allowed measurement of vertical angles. Verniers allowed measurement to a fraction of a degree, such as with a turn-of-the-century transit. The plane table provided a graphical method of recording and measuring angles, which reduced the amount of mathematics required. In Francis Ronalds invented a reflecting instrument for recording angles graphically by modifying the octant. This is called a close. If the first and last bearings are different, this shows the error in the survey, called the angular misclose. The surveyor can use this information to prove that the work meets the expected standards. When more precise measurements are needed, means like precise levels also known as differential leveling are used. When precise leveling, a series of measurements between two points are taken using an instrument and a measuring rod. Differences in height between the measurements are added and subtracted in a series to get the net difference in elevation between the two endpoints. Usually GPS is somewhat less accurate than traditional precise leveling, but may be similar over long distances. When using an optical level, the endpoint may be out of the effective range of the instrument. There may be obstructions or large changes of elevation between the endpoints. In these situations, extra setups are needed. Turning is a term used when referring to moving the level to take an elevation shot from a different location. To "turn" the level, one must first take a reading and record the elevation of the point the rod is located on. While the rod is being kept in exactly the same location, the level is moved to a new location where the rod is still visible. A reading is taken from the new location of the level and the height difference is used to find the new elevation of the level gun. This is repeated until the series of measurements is completed. The level must be horizontal to get a valid measurement. Because of this, if the horizontal crosshair of the instrument is lower than the base of the rod, the surveyor will not be able to sight the rod and get a reading. The rod can usually be raised up to 25 feet high, allowing the level to be set much higher than the base of the rod. Observations to the sun, moon and stars could all be made using navigational techniques. The point can then be used as a base for further observations. Survey-accurate astronomic positions were difficult to observe and calculate and so tended to be a base off which many other measurements were made. Since the advent of the GPS system, astronomic observations are rare as GPS allows adequate positions to be determined over most of the surface of the earth. Geodetic network A survey using traverse and offset measurements to record the location of the shoreline shown in blue. Black dashed lines are traverse measurements between reference points black circles. The red lines are offsets measured at right angles to the traverse lines. Few survey positions are derived from first principles. Instead, most surveys points are measured relative to previous measured points. This forms a reference or control network where each point can be used by a surveyor to determine their own position when beginning a new survey. The surveyors can set up their instruments on this position and measure to nearby objects. Sometimes a tall, distinctive feature such as a steeple or radio aerial has its position calculated as a reference point that angles can be measured against. It can determine distances, elevations and directions between distant objects. Since the early days of surveying, this was the primary method of determining accurate positions of objects for topographic maps of large areas. A surveyor first needs to know the horizontal distance between two of the objects, known as the baseline. Then the heights, distances and angular position of other objects can be derived, as long as they are visible from one of the original objects. High-accuracy transits or theodolites were used, and angle measurements repeated for increased accuracy. See also Triangulation in three dimensions. Offsetting is an alternate method of determining position of objects, and was often used to measure imprecise features such as riverbanks. The surveyor would mark and measure two known positions on the ground roughly parallel to the feature, and mark out a baseline between them. At regular intervals, a distance was measured at right angles from the first line to the feature. Page 5

6 Chapter 5 : Types of Land Survey-Definition, Principle & Methods of Land Surveying Note: Citations are based on reference standards. However, formatting rules can vary widely between applications and fields of interest or study. The specific requirements or preferences of your reviewing publisher, classroom teacher, institution or organization should be applied. Chapter 6 : Geodetic Surveying: Definition, Use and Classification Geodetic surveying is the survey in which the curvature of the earth is taken into account and higher degree of accuracy in linear and angular observations is achieved. The geodetic surveys extend over large areas and lines connecting any two points on the surface of the earth are treated as arcs. Chapter 7 : Plane And Geodetic Surveying For Engineers. Vol racedaydvl.com Surveying by Clark David e Plane and Geodetic Surveying blends theory and practice, conventional techniques and GPS, to provide the ideal book for students of surveying. Detailed guidance is given on how and when the principle surveying instruments (theodolites, Total Stations, levels and GPS) should be used. Chapter 8 : Plane And Geodetic Surveying For Engineers by David Clark Plane And Geodetic Surveying For Engineers. Plane Surveying. Clark David. Book and Jacket are both in Very good condition throughout. Publish Year Publish Place:London. ebay! Chapter 9 : difference between plane surveying and geodetic surveying Plane Surveying vs Geodetic Surveying. Surveying can simply be defined as the process or technology of making measurement in a scientific manner on, above, or below the earth's surface in order to determine points to produce a plan or map. Page 6

GEOMATICS ENGINEERING / SURVEYING

1 GEOMATICS ENGINEERING / SURVEYING CHAPTER 1 Dr. Muhammad Ashraf Javid Assistant Professor Department of Civil and Environmental Engineering Email: muhammad.javid@unizwa.edu.om 2 Geomatics Engineering