IntroductionAlmost every remote sensing exercise will require field surveys at some stage. For example, field surveys may be needed to define habitats, calibrate remotely sensed imagery (e.g. provide quantitative measurements of suspended sediments in surface waters), or for testing the accuracy of remote sensing outputs. This chapter aims to describe some of the key generic issues that must be borne in mind when planning a field survey. Specifically, the chapter sets out the general considerations involved in surveying coastal habitats, describes the importance of recording the positions of survey sites usingGlobal Positioning Systems (GPS), and gives an introduction to the costs of field survey (costs are explored further in The importance of assessing the accuracy of remote sensing outputs is stressed and guidance given on appropriate statistical methods for calculating the accuracy of habitat maps. Specific coral reef, seagrass and mangrove field survey methods (Plate 5) are too varied to include here and are discussed in Chapters11, 12 and 13 respectively. The need for field survey Before the need for field survey is discussed, it is worth briefly reviewing the concept of remote sensing. Remote sensing provides a synoptic portrait of the Earths surface by recording numerical information on the radiance measured in eachpixelin each spectralbandof the image being studied. To create a habitat map, the operator must instruct the computer to treat certain referencepixelsas belonging to specific habitats. The computer then creates a spectralsignature for each habitat and proceeds to code every otherpixelin the image accordingly, thus creating a thematic map.Historically, some researchers have looked upon remote sensing as a means of mapping without the need to conduct field work. Whether this is an appropriate tenet depends on the objective of the study and familiarity of the operator with the study site. On a general basis, most people can view a satellite image or aerial photograph and easily distinguish different features according to their colour,contrast, pattern, texture and context. In some instances instances, this may be all that is required to make use of the imagery. For example, visual interpretation is usually sufficient to delineate the shape of coastlines. In the majority of studies, however, the objective is more sophisticated (e.g. mapping submerged habitats) and the thematician may not be able to draw on visual interpretation and background knowledge to identify each habitat type. In fact, the thematician is unlikely to be aware of the variety of habitat types in the image. Our own experience supports this view (seeChapter 9): even when moderately familiar with an area (the Caicos Bank), theoverall accuracyof the final map was low if field surveys were not conducted (e.g. 1530%).The aims of field survey are three-fold. Firstly, to identify each feature of interest (e. g. each habitat type). Secondly, to locate representative areas of each feature in order to generate spectralsignatures(spectra) from the imagery. Thirdly, to generate adequate additional data to test the quality or accuracy of the imageclassification(i.e. habitat map). This latter consideration is extremely important for any mapping exercise. In a coastal management context, imagine the legal problems in suggesting that a developer had cleared a particular mangrove area if the accuracy of mangrove maps were unknown. Taken a step further, where do decision makers stand legally if offenders are fined according to the extent of habitat that they have illegally destroyed? Legal problems may not be the only consequence. In biological terms, management initiatives based on a habitat map of unknown accuracy could lead to unnecessary or inappropriate action, although it is difficult to predict or generalise specific problems arising from such circumstances. Surprisingly though, accuracy assessments are fairly scarce in the context of mapping tropical coastal resources.

Planning field surveysField surveys must be planned carefully and due consideration must be given to the objectives of the study and the nature of habitats being surveyed. These issues will dictate most aspects of survey design, such as the sampling strategy, sampling technique, sampling unit, amount of replication, time to survey (i.e. weather conditions, date of image acquisition), ancillary data (e.g. depth, water turbidity) and the means of geographically referencing data. Specific considerations on methods, sampling units and ancillary data are described in the relevant chapters of this handbook (i.e. for mapping coral reefs, seagrass beds and mangroves) but more general comments are made here.

Estimate costs of field surveyField surveys are expensive and not all of the costs incurred in gathering field data and relating it to remotely sensed data are immediately obvious. However, a full analysis of field costs is vital when designing a remote sensing campaign to ensure that realistic budgets and work schedules are planned. A generalised discussion of costs is presented here. Detailed advice on planning a remote sensing field campaign in terms of cost and the actual costs incurred in mapping the habitats of the Turks and Caicos Islands are given in

What is accuracy?Accuracy is referred to in many different contexts throughout this book. The accuracy of aGPSposition fix is a measure of the absolute closeness of that fix to the correct coordinates, whereas positional accuracy refers to the accuracy of a geometrically corrected image and is measured with the root mean square (Chapter 6). This section is concerned with thematic accuracy, that is, the non-positional characteristics of spatial data. If data have been subjected to multispectralclassificationthen thematic accuracy is also known asclassificationaccuracy (Stehmen 1997). This accuracy refers to the correspondence between the class label and the true class, which is generally defined as what is observed on the ground during field surveys. In other words, how much of the class labelled as seagrass on a classified image is actually seagrassin situ.

Surveying

This article is about measuring positions on Earth. For other uses, seeSurvey.at zero chainage at Katra to Maihar Distt. Road

A surveyor at work with an infrared reflector used for distance measurement.Surveyingorland surveyingis the technique, profession, and science of determining the terrestrial or three-dimensional position of points and the distances and angles between them. A surveying professional is called aSurveyor. These points are usually on the surface of the Earth, and they are often used to establish landmapsand boundaries forownership, locations like building corners or the surface location of subsurface features, or other purposes required by government or civil law, such as property sales.

Surveyors work with elements ofmathematics(geometryandtrigonometry),physics,engineeringand thelaw. They use equipment liketotal stations, robotic total stations, GPS receivers, prisms,3D scanners, radios, handheld tablets, digital levels, andsurveying software.Surveying has been an element in the development of the human environment since the beginning of recorded history. The planning and execution of most forms ofconstructionrequire it. It is also used intransport,communications, mapping, and the definition of legal boundaries for land ownership.

HistoryModern surveyingAbel Foullon described aplane tablein 1551, but it is thought that the instrument was in use earlier as his description is of a developed instrument.Gunter's chainwas introduced in 1620 by English mathematicianEdmund Gunter. It enabled plots of land to be accurately surveyed and plotted for legal and commercial purposes.

Table of Surveying, 1728CyclopaediaIn the 18th century, modern techniques and instruments for surveying began to be used.Jesse Ramsdenintroduced the first precisiontheodolitein 1787. It was an instrument for measuringanglesin the horizontal and vertical planes. He created hisgreat theodoliteusing an accuratedividing engineof his own design.Leonard Digges, Joshua Habermel andJonathan Sisson[4]invented more primitive devices in the previous centuries, but Ramsden's theodolite represented a great step forward in the instrument's accuracy.William Gascoigneinvented an instrument that used atelescopewith an installedcrosshairas a target device, in 1640.James Wattdeveloped an optical meter for the measuring of distance in 1771; it measured theparallactic anglefrom which the distance to a point could be deduced.Dutch mathematicianWillebrord Snellius(a.k.a. Snell) introduced the modern systematic use oftriangulation. In 1615 he surveyed the distance fromAlkmaartoBergen op Zoom, approximately 70 miles (110 kilometres). The survey was a chain of quadrangles containing 33 triangles in all. Snell calculated how the planar formulae could be corrected to allow for the curvature of the earth. He also showed how toresection, or calculate, the position of a point inside a triangle using the angles cast between the vertices at the unknown point. These could be measured more accurately than bearings of the vertices, which depended on a compass. His work established the idea of surveying a primary network of control points, and locating subsidiary points inside the primary network later. Between 1733 and 1740,Jacques Cassiniand his sonCsarundertook the first triangulation ofFrance. They included a re-surveying of themeridian arc, leading to the publication in 1745 of the first map of France constructed on rigorous principles. By this time, triangulation methods were by then well established for local map-making,

Surveying equipment

Chain (unit)From Wikipedia, the free encyclopedia1 chain=

SI units

20.1168m2,011.68cm

US customary/Imperial units

22.0000yd66.0000ft

Achainis aunitoflength. It measures 66feet, or 22yards, or 100links,[1]or 4rods(20.1168m). There are 10 chains in afurlong, and 80 chains in onestatute mile. Anacreis the area of 10 square chains (that is, an area of one chain by one furlong). The chain has been used for several centuries in Britain and in some other countries influenced by British practice.By extension,chainage(running distance) is the distance along a curved or straight survey line from a fixed commencing point, as given by anodometer.Origin[edit]The chain was commonly used with the mile to indicate land distances and in particular in surveying land for legal and commercial purposes. In medieval times, local measures were commonly used, and many units were adopted that gave manageable units; for example the distance from London to York could be quoted in inches, but the resulting huge number would be unmemorable. The locally used units were often inconsistent from place to place.

In 1620, the clergymanEdmund Gunterdeveloped a method of surveying land accurately with low technology equipment, using what became known asGunter's chain; this was 66 feet long and from the practice of using his chain, the word transferred to the actual measured unit. His chain had 100links, and the link is used as a subdivision of the chain as a unit of length.In countries influenced by English practice, land plans prepared before about 1960 associated with the sale of land usually have lengths marked in chains and links, and the areas of land parcels are indicated inacres. A rectangle of land onefurlongin length and one chain in width has an area of one acre. It is sometimes suggested that this was a medieval parcel of land capable of being worked by one man and supporting one family, but there is no documentary support for this assertion, and it would in any case have predated Gunter's work.

The main surveying instruments in use around the world are thetheodoliteand steel band, thetotal station, thelevelandrodand surveying GPS systems. Most instruments screw onto atripodwhen in use. Tape measures are often used for measurement of smaller distances. 3D scanners and various forms of aerial imagery are also used.TheTheodoliteis an instrument for the measurement of angles. It uses two separatecircles,protractorsoralidadesto 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 vertical 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.TheGyrotheodoliteis a form of theodolite that uses a gyroscope to orient itself in the absence of reference marks. It is used in underground applications.Thetotal stationis 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.[citation needed]Modern top-of-the-line total stations no longer need a reflector or prism to return the light pulses used for distance measurements. They are fully robotic, and can even e-mail point data to a remote computer and connect tosatellite positioning systems, such asGlobal Positioning System.Real Time KinematicGPS systems have increased the speed of surveying, but they are still only horizontally accurate to about 20mm and vertically to 3040mm.[8]GPS surveying differs from other GPS users in the equipment and methods used. 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. This produces an accurate baseline that can be over 20km long. 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. To increase precision, surveyors placebeaconson the ground (about 20km (12mi) apart). This method reaches precisions between 540cm (depending on flight height).[9]Surveyors use ancillary equipment such as tripods and instrument stands, staves and beacons used for sighting purposes,PPE, vegetation clearing equipment, digging implements for finding survey markers buried over time, hammers for placements of markers in various surfaces and structures, and portable radios for communication over long lines of sight.Distance measurementBefore EDM devices,distanceswere measured using a variety of means. These included chains having links of a known length such as aGunter's chain, or measuring tapes made ofsteelorinvar. 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 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.Tacheometryis 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 measurementHistorically, horizontal angles were measured by using acompassto provide a magnetic bearing. The deflection from the bearing was recorded. Later, more precise scribed discs later improved better angular resolution. Mounting telescopes withreticlesatop the disc allowed more precise sighting. (seetheodolite). Levels and calibrated circles allowed measurement of vertical angles.verniersallowed measurement to a fraction of a degree, such as with a turn-of-the-centurytransit.The Plane table provided a graphical method of recording and measuring angles, which reduced the amount of mathematics required.By observing the bearing from every vertex in a figure, a surveyor can measure around the figure. The final observation will be between the two points first observed, except with a 180 difference. This is called aclose. If the first and last bearings are different, this shows the error in the survey, called theangular misclose. The surveyor can use this information to prove that the work meets the expected standards.

Leveling

The simplest method for measuring height is with analtimeterusing air pressure to find height. 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. With theGlobal Positioning System(GPS), elevation can be measured with satellite receivers. 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.Turningis 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.

Datum and coordinate systemsMany surveys do not calculate positions on the surface of the earth, but instead measure the relative positions of objects. However, often the surveyed items need to be compared to outside data, such as boundary lines or previous surveys objects. The oldest way of describing a position is via latitude and longitude, and often a height above sea level. As the surveying profession grew it created Cartesian coordinate systems to simplify the mathematics for surveys over small parts of the earth. The simplest coordinate systems assume that the earth is flat and measure from an arbitrary point, known as a 'datum' (singular form of data). The coordinate system allows easy calculation of the distances and direction between objects over small areas. Large areas distort due to the earth's curvature. North is often defined as true north at the datum.For larger regions, it is necessary to model the shape of the earth using an ellipsoid or a geoid. Many countries have created coordinate-grids customized to lessen error in their area of the earth.

The surveying profession

The basic principles of surveying have changed little over the ages, but the tools used by surveyors have evolved. Engineering, especiallycivil engineering, often needs surveyors.Surveyors help determine the placement ofroads,railways,reservoirs,dams,pipeline transports,retaining walls,bridges, or buildings. They establish the boundaries of legal descriptions and political divisions. They also provide advice and data forgeographical information systems(GIS) that record land features and boundaries.Surveyors must have a thorough knowledge ofalgebra, basiccalculus,geometry, andtrigonometry. They must also know the laws that deal with surveys,real property, andcontracts.Most jurisdictions recognize three different levels of qualification:Survey assistantsorchainmenare usually unskilled workers who help the surveyor. They place target reflectors, find old reference marks, and mark points on the ground. The term 'chainman' derives from past use ofmeasuring chains. An assistant would move the far end of the chain under the surveyor's direction.Survey techniciansoften operate survey instruments, run surveys in the field, do survey calculations, or draft plans. A technician usually has no legal authority and cannot certify his work. Not all tehnicians are qualified, but qualifications at the certificate or diploma level are available.Licensed, registered, or chartered surveyorsusually hold a degree or higher qualification. They are often required to pass further exams to join a professional association or to gain certifying status. Surveyors are responsible for planning and management of surveys. They have to ensure that their surveys, or surveys performed under their supervision, meet the necessary legal standards. Manyprincipals of surveying firmshold this status.

Cadastral land surveyorsare licensed by governments. In the United States, the federal government conducts most cadastral surveys through the cadastral survey branch of theBureau of Land Management(BLM).[11]They consult withForest Service,National Park Service,Army Corps of Engineers,Bureau of Indian Affairs,Fish and Wildlife Service,Bureau of Reclamation, and others. The BLM used to be known as theGeneral Land Office(GLO).In states organized per thePublic Land Survey System(PLSS), surveyors must carry out BLM cadastral surveys under that system.Cadastral surveyors often have to work around changes to the earth that obliterate or damage boundary monuments. When this happens, they must consider evidence that is not recorded on the title deed. This is known as extrinsic evidence.[12]

Surveying has traditionally been defined as the science and art of determining relative positions of points above, on, or beneath the surface of the earth, or establishing such points. In a more general sense, however, surveying can be regarded as that discipline which encompasses all methods of gathering and processing information about the physical earth and environment,. Conventional ground systems are now supplemented by aerial and satellite surveying methods, which evolved through the defense and space programs.In general, the work of a surveyor can be divided into five parts:1. Research analysis and decision making. Selecting the survey method, equipment, most likely corner locations, and so on.2. Field work or data acquisition. Making measurements and recording data in the field.3. Computing or data processing. Performing calculations based on the recorded data to determine locations, areas, volumes, and so on.4. Mapping or data representation. Plotting measurements or computed values to produce a map, plat, or chart, or portraying the data in numerical or computer format.5. Stakeout. Setting monuments and stakes to delineate boundaries or guide construction operations.Surveying is one of the oldest and most important arts practiced by bman because from the earliest times it has been necessary to mark boundaries and divide land. Surveying has now become indispensable to our modern way of life.Surveying continues to play an extremely important role in many branches of engineering. For example, surveys are required to plan, construct, and maintain highways, railroads, buildings, bridges, tunnels, canals, land subdivisions, seweage systems, pipelines, etc. All engineers must know the limits of accuracy possible in construction.

Leveling

CHAPTER 2 ROAD SURVEYING Section I. RECONNAISSANCE SURVEY PREPARATION AND SCOPE The reconnaissance survey is an extensive study of an entire area that might be used for a road or airfield. Its purpose is to eliminate those routes or sites which are impractical or unfeasible and to identify the more promising routes or sites. Existing maps and aerial photographs may be of great help. Contour maps show the terrain features and the relief of an area. Aerial photographs show up-to-date planimetric details. The reconnaissance survey must include all possible routes and sites. The reconnaissance survey report should summarize all the collected information, including a description of each route or site, a conclusion on the economy of its use, and, where possible, appropriate maps and aerial photographs. Design Design and military characteristics should be considered during the reconnaissance survey. Keep in mind that future operations may require an expanded road net.

A study of the route plans and specifications is necessary. If these are unavailable, use the following as guides. Locate portions of the new road along or over existing roads, railroads, or trails, whenever possible. Locate the road on high-bearing-strength soil that is stable and easily drained, avoiding swamps, marshes, and organic soil. Locate the road along ridges and streamlines, keeping drainage structures to a minimum. Keep the grade well above the high waterline when following a stream. Select a route as near to sources of material as practical, and locate the road along contour lines to avoid unnecessary earth work. Locate the road on the sunny side of hills and canyons, and on that side of the canyon wall where the inclination of the strata tends to support the road rather than cause the road to slide into the canyon. Locate roads in forward combat zones so that they are concealed and protected from enemy fire. This may at times conflict with engineering considerations. Select locations which conserve engineer assets, avoiding rockwork and excessive clearing. Level Party The level party establishes benchmarks and determines the elevation of selected points along the route to provide control for future surveys, such as the preparation of a topographic map or profile and cross-section leveling. The level party takes rod readings and records elevations to the nearest 0.01 foot or 0.001 meter. It sets the benchmarks in a place well out of the area of construction and marks them in such a way that they will remain in place throughout the whole project. If there is no established vertical control point available, establish an arbitrary elevation that may be tied to a vertical control point later. An assigned value for an arbitrary elevation must be large enough to avoid negative elevations at any point on the project. Topographic Party The topographic party secures enough relief and planimetric detail within the prescribed area to locate any obstacles and allow preparation of rough profiles and cross sections.

Survey & leveling

53 | Page

CenterLHSRHS

100.19599.785100.42

99.97100.2999.97

100.7599.8999.885

100.8599.995100.045

99.97100.59100.29

101.255100.62100.68

100.799.8299.82

100.7599.07100.77

100.0699.97100.21

100.8199.78100.34

100.57100.0199.85

100.7599.91100.76

100.67100.05100.38

100.73100.225100.02

100.75100.41100.41

100.695100.07100.07

98.3398.77598.33

98.8298.71598.01

98.7998.3698.31

98.77598.7598.33

98.78598.1298.315

98.76598.29598.42

97.04597.36597.045

97.9396.96597.705

98.13996.0696.36

98.0196.5796.53

98.0197.0196.815

98.0496.9996.74

98.0296.8496.87

98.2296.12598.22

94.393.2492.865

94.3593.2792.92

94.4192.9693.065

94.4793.47593.31

94.49593.7693.27

89.9189.9190.07

91.0790.28590.915

91.08590.0790.155

91.190.07590.18

91.1989.82589.78

91.2690.5990.14

91.2990.1690.16

90.69590.0289.56

90.80590.2190.09

90.9190.23589.78

91.0490.21890.95

91.1989.4490.05

91.33590.3290.825

91.6190.8691.11

89.2190.33590.04

90.5489.2190.08

90.6288.5288.64

90.7288.6188.72

90.82590.19589.81

90.19589.1690.87

90.9789.16

91.0189.695

91.2389.65

91.39589.765

91.62

89.75

91.7690.89

91.7791.0390.685

91.3590.84

91.6190.08

91.4591.0391.75

91.31590.7690.82

91.0290.5990.48

91.1490.5190.235

91.09590.5190.11

89.82

Preliminary work in road construction is surveying & leveling works. This consists of Traverse Survey, TBM Survey, and Centre Line Setting out, Centre Line marking, Cross Section Survey and Submittal of Drawings.

Traverse SurveyTRAVERSE SURVEYING

Traverse Surveying is a popular method of surveying. This article includes definition of traverse surveying along with its classification,errors in traversing, checks, the completed method of traversing and plotting of traverse survey.DEFINITION

Traversing is that type of survey in which a number of connected survey lines form the framework and the directions and lengths of the survey lines are measured with the help of an angle measuring instrument and a tape or chain respectively.

At the commencement of contract all the basic traverse points will be checked and if any are found to be missing or appear to have been disturbed, necessary arrangements should be made to re-establish the points and traverse survey is carried out after that.TBM TraversTBM traverse is done to establish the reduce levels of each and every TBM with reference to the Permanent bench marks established by us. Engineering level is used to establish TBMs.Centre Line MarkingCenterline marking is the primary survey part in road construction. Centerline is useful while setting out for any road construction work. So it is very essential marking centre line first, before any construction work.Equipment using for centre line marking Linen tape Road marking paint Nylon cord concrete nailsSafety equipment (e.g. Traffic cones, Bastinade boards etc.)Centre Line Setting Out And Marking

Using total stations and approved coordinates of control points, the road centre line should be marked at every 10m interval on the road. With the aid of rope and road marking paint, the centre points marked in every 10m intervals of the road should be extended as a centre line and that established centerline should be maintained until the end of the project.

Chain age MarkingChain age marking is done to describe the location of the road. Chain age should be marked on the road centre line in each 20m and 100m interval with meter and kilometer interval respectively.Equipment used for chain age marking Linen tape Road marking paint Nylon cord Concrete nails Ranging rods Compass TheodoliteSafety equipment (e.g. Traffic cones, Barricade boards etc.)Process of chain age marking Lay the nylon cord through the 10m interval centre points and draw the centerline using chalk. Write the chain ages using road paint.

Designed Data Of Traverse Survey

SIEVE ANALYSIS

Sieve analysis helps to determine the particle size distribution of the coarse and fine aggregates.This is done by sieving the aggregates as per IS: 2386 (Part I) 1963. In this we use different sieves as standardized by the IS code and then pass aggregates through them and thus collect different sized particles left over different sieves.The apparatus used are i) A set of IS Sieves of sizes 80mm, 63mm, 50mm, 40mm,31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 6.3mm,4.75mm, 3.35mm, 2.36mm, 1.18mm, 600m, 300m, 150m and 75m.ii) Balance or scale with an accuracy to measure 0.1 percent of the weight of the test sample.The weight of sample available should not be less than the weight given below:-

The sample for sieving should be prepared from the larger sample either by quartering or by means of a sample divider.Procedure to determine particle size distribution of Aggregates.i) The test sample is dried to a constant weight at a temperature of 110 + 5oC and weighed.ii) The sample is sieved by using a set of IS Sieves.iii) On completion of sieving, the material on each sieve is weighed.iv) Cumulative weight passing through each sieve is calculated as a percentage of the total sample weight.v) Fineness modulus is obtained by adding cumulative percentage of aggregates retained on each sieve and dividing the sum by 100.Reporting of Results

The results should be calculated and reported as:i) the cumulative percentage by weight of the total sampleii) the percentage by weight of the total sample passing through one sieve and retained on the next smaller sieve, to the nearest 0.1 percent. The results of the sieve analysis may be recorded graphically on a semi-log graph with particle size as abscissa (log scale) and the percentage smaller than the specified diameter as ordinate.

WBM (Water Bound Macadam)MacadamFrom Wikipedia, the free encyclopediaFor the Scottish family name, seeMcAdam (disambiguation). For the regions of imperceptible colour differences, seeMacAdam ellipse.

Macadam country roadMacadamis a type ofroad constructionpioneered by Scottish engineerJohn Loudon McAdamaround 1820. The method simplified what had been considered state of the art at that point. Single-sizedaggregatelayers of small stones, with a coating of binder as a cementing agent, are mixed in an open-structured roadway. 1Predecessors 1.1Pierre-Marie-Jrme Trsaguet 1.2Thomas Telford 2Advent of the macadam 2.1John McAdam 2.2McAdam's methods 2.3The first macadam in North America 2.4McAdam's influence 3Water-bound macadam 4Tar-bound macadam 5See also 6References 7Further reading 8External links Predecessors[edit]Water-bound macadamMcAdam's road building technology was applied to roads by otherengineers. One of these engineers was Richard Edgeworth, who filled the gaps between the surface stones with a mixture of stone dust and water, providing a smoother surface for the increased traffic using the roads.[18]This basic method of construction is sometimes known aswater-bound macadam. Although this method required a great deal of manual labour, it resulted in a strong and free-draining pavement. Roads constructed in this manner were described as "macadamized."[18]

Construction of WBM roads

(I) - WBM (Water Bound macadam) roads construction:

The water bound macadam road construction technique was given by the John Macadam. This technique in present day is used as given below.For WBM construction we use three materials:1. Aggregates2. Screeners3. Binders.Aggregates:We use the aggregates of different grades. IRC(Indian Roads Congress) has classified the coarse aggregates into 9 grades, according to their size.

For the construction of the WBM roads aggregates are used in the sub-base, base and surface course and so the aggregates are divided into 3 grades according to their size.Grade 1 - particles of size 90 mm to 40 mm.Grade 2 - particles of size 63 to 40 mm.Grade 3 - particles of size 50 to 20 mm.The grade 1 aggregates having size of 90 mm to 40 mm are preferred for the sub-base material and grade 2 for the base and grade 1 for the surface course. However, if we only use the WBM as the surface course, it gets deteriorated fast due to abrasion with the traffic so, bituminous surfacing over the WBM is general practice.Screenersare the aggregates of the smaller sizes, generally 12.5 mm or 10 mm, for grade A and grade B. They are of the same chemical composition as of the coarse aggregates. For economic considerations IRC has suggested non plastic materials such as, crushed over burnt bricks, moorum, gravels, etc. provided the liquid limit of the material is less than 20%, plasticity index is less than 6.0% and the portion of fines passing 0.075 mm sieve is less than 10%. However if crush-able type of aggregates are used, use of the screeners may be disposed off.

Binders: Binders, are the layers of materials which are laid after the compaction of the aggregates and the screening materials one after the another. Kankar dust or lime stone dust may be utilized if locally available. The binding material with plasticity index value of 4% to 9% is used in surface course construction; the plasticity index of binding course material should be less than 6% in the case of the WBM layers used as base course or sub-base course, with bituminous surfacing. However if the screening used are of crushable material like moorum or soft gravel, there is no need to apply binding material, unless the plasticity index value is low. (II) - WMM(Wet mix macadam)road construction:Aggregates used are of the smaller sizes, varies between the 4.75 mm to 20 mm sizes and the binders(stone dust or quarry dust having PI(Plasticity Index) not less than 6%) are premixed in a batching plant or in a mixing machine. Then they are brought to the site for overlaying and compaction.

The PI(plasticity Index) of the binding material is kept low because it should be a sound and non plastic material. If the plasticity index is more then there are the chances of the swelling and more water retention properties. So this value should be kept in mind.

WBM ROAD CONSTRUCTION WBM Stands for Water Bound Macadam which is the most commonly used road construction procedure for over more than 190 years.Pioneered by Scottish Engineer John Loudon McAdam around 1820 Macadam is a type of Road Construction. The broken stones of base and surface course,if any are bound by the stone dust is presence of moisture is called WBM Roads.Macadam means the pavement base course made of crushed or broken aggregate mechanically interlocked by rolling and the voids filled with screening and binding material with the assistance of water.WBM may be used as a sub-base,base or a surface course.The thickness of each compacted layer of WBM ranges from 10cm to 7.5cm depending on size and the gradation ofaggregateused.

Construction Procedure:1.Prepare the foundation for receiving the WBM course.2.Lateral confinement may be done by compacting the shoulder to advance,to a thickness equal to that of the compacted WBM layer and by trimming the inner side vertically.3.Spreading ofCoarse Aggregate.

4.Compaction ofcoarse aggregateis done by wheeled power roller of capacity 6 to 10 tonnes or alternately by an equivalent vibratory roller.

5.Dry screening is applied gradually over the surface to fill the interstices in these.6.The surface is sprinkled with water,swept and rolled.7.Binding material is applied at a uniform and slow rate at two and more layers.8.WBM Coarse is allowed to set overnight.

VERTICAL CURVE DESIGN

Parabolic Formulation

A Road Through Hilly Terrain with Vertical Curves in New Hampshire

A Typical Crest Vertical Curve (Profile View)Two types of vertical curves exist: (1) Sag Curves and (2) Crest Curves. Sag curves are used where the change in grade is positive, such as valleys, while crest curves are used when the change in grade is negative, such as hills. Both types of curves have three defined points: PVC (Point of Vertical Curve), PVI (Point of Vertical Intersection), and PVT (Point of Vertical Tangency). PVC is the start point of the curve while the PVT is the end point. The elevation at either of these points can be computed asandfor PVC and PVT respectively. The roadway grade that approaches the PVC is defined asand the roadway grade that leaves the PVT is defined as. These grades are generally described as being in units of (m/m) or (ft/ft), depending on unit type chosen.Both types of curves are in parabolic form. Parabolic functions have been found suitable for this case because they provide a constant rate of change of slope and imply equal curve tangents, which will be discussed shortly. The general form of the parabolic equation is defined below, whereis the elevation for the parabola.

At x = 0, which refers to the position along the curve that corresponds to the PVC, the elevation equals the elevation of the PVC. Thus, the value ofequals. Similarly, the slope of the curve at x = 0 equals the incoming slope at the PVC, or. Thus, the value ofequals. When looking at the second derivative, which equals the rate of slope change, a value forcan be determined.

Thus, the parabolic formula for a vertical curve can be illustrated.

Where: : elevation of the PVC : Initial Roadway Grade (m/m) : Final Roadway Grade (m/m) : Length of Curve (m)Most vertical curves are designed to be Equal Tangent Curves. For an Equal Tangent Curve, the horizontal length between the PVC and PVI equals the horizontal length between the PVI and the PVT. These curves are generally easier to design.OffsetSome additional properties of vertical curves exist. Offsets, which are vertical distances from the initial tangent to the curve, play a significant role in vertical curve design. The formula for determining offset is listed below.

Where: : The absolute difference betweenand, multiplied by 100 to translate to a percentage : Curve Length : Horizontal distance from PVC along curveStopping Sight DistanceSight distance is dependent on the type of curve used and the design speed. For crest curves, sight distance is limited by the curve itself, as the curve is the obstruction. For sag curves, sight distance is generally only limited by headlight range. AASHTO has several tables for sag and crest curves that recommend rates of curvature,, given a design speed or stopping sight distance. These rates of curvature can then be multiplied by the absolute slope change percentage,to find the recommended curve length,.

Without the aid of tables, curve length can still be calculated. Formulas have been derived to determine the minimum curve length for required sight distance for an equal tangent curve, depending on whether the curve is a sag or a crest. Sight distance can be computed from formulas in other sections (SeeSight Distance).Crest Vertical CurvesThe correct equation is dependent on the design speed. If the sight distance is found to be less than the curve length, the first formula below is used, whereas the second is used for sight distances that are greater than the curve length. Generally, this requires computation of both to see which is true if curve length cannot be estimated beforehand.

Where: : Minimum Curve Length (m) : The absolute difference betweenand, multiplied by 100 to translate to a percentage : Sight Distance (m) : Height of driver's eye above roadway surface (m) : Height of objective above roadway surface (m)Sag Vertical CurvesJust like with crest curves, the correct equation is dependent on the design speed. If the sight distance is found to be less than the curve length, the first formula below is used, whereas the second is used for sight distances that are greater than the curve length. Generally, this requires computation of both to see which is true if curve length cannot be estimated beforehand.

Where: : The absolute difference betweenand, multiplied by 100 to translate to a percentage : Sight Distance (m) : Height of headlight (m) : Inclined angle of headlight beam, in degrees

To find the position of the low point on a SAG vertical curve: x is the horizontal distance between the PVC and Low Point

: Grade Down (%) : Grade Up (%) : Length of Vertical Curve (station) ei. 600 ft =6Passing Sight DistanceIn addition to stopping sight distance, there may be instances where passing may be allowed on vertical curves. For sag curves, this is not an issue, as even at night, a vehicle in the opposing can be seen from quite a distance (with the aid of the vehicle's headlights). For crest curves, however, it is still necessary to take into account. Like with the stopping sight distance, two formulas are available to answer the minimum length question, depending on whether the passing sight distance is greater than or less than the curve length. These formulas use units that are in metric.

Where: : The absolute difference betweenand, multiplied by 100 to translate to a percentage : Passing Sight Distance (m) : Minimum curve length (m)

References1. Jump up^Johnson, Anthony,Solving Stonehenge: The New Key to an Ancient Enigma. (Thames & Hudson, 2008)ISBN 978-0-500-05155-92. Jump up^Hong-Sen Yan & Marco Ceccarelli (2009),International Symposium on History of Machines and Mechanisms: Proceedings of HMM 2008,Springer, p.107,ISBN1-4020-9484-13. Jump up^Lewis, M. J. T. (2001-04-23).Surveying Instruments of Greece and Rome. Cambridge University Press.ISBN9780521792974. Retrieved30 August2012.4. Jump up^Turner, Gerard L'E.Nineteenth Century Scientific Instruments, Sotheby Publications, 1983,ISBN 0-85667-170-35. Jump up^Sturman, Brian; Wright, Alan."The History of the Tellurometer"(PDF).http://www.fig.net/. International Federation of Surveyors. Retrieved20 July2014.6. Jump up^Cheves, Marc."Geodimeter-The First Name in EDM".http://www.profsurv.com/magazine/. Retrieved2014-07-20.7. Jump up^Mahun, Jerry."Electronic Distance Measurement".Jerrymahun.com. Retrieved2014-07-20.8. Jump up^National Cooperative Highway Research Program:Collecting, Processing and Integrating GPS data into GIS, p. 40. Published by Transportation Research Board, 2002 ISBN 0-309-06916-5, ISBN 978-0-309-06916-89. Jump up^Toni Schenk, Suyoung Seo, Beata Csatho:Accuracy Study of Airborne Laser Scanning Data with Photogrammetry, p. 11810. Jump up^Kahmen, Heribert; Faig, Wolfgang (1988).Surveying. Berlin: de Gruyter. p.9.ISBN3-11-008303-5. Retrieved2014-08-10.11. Jump up^A History of the Rectangular Survey System by C. Albert White, 1983, Pub: Washington, D.C.: U.S. Dept. of the Interior, Bureau of Land Management: For sale by Supt. of Docs., U.S. G.P.O.,12. Jump up^Richards, D., & Hermansen, K. (1995). Use of extrinsic evidence to aid interpretation of deeds. Journal of Surveying Engineering, (121), 178.13. The Cassell English Dictionary, London 1990, p. 214,ISBN 0-304-34003-014. Jump up^Plane and Geodetic Surveying, A.L. Johnson (SPON)15. Jump up^HS2 proposed alignment with chainages expressed in metres16. ^Jump up to:abGeorge Seddon (28 September 1998).Landprints: Reflections on Place and Landscape. Cambridge University Press. pp.151.ISBN978-0-521-65999-4. Retrieved28 May2013.17. Jump up^Lay, M. G. (July 2008)."Roads".emelbourne the city past and present. School of Historical Studies Department of History, The University of Melbourne. Retrieved28 May2013.18. Jump up^Documents19. Jump up^Picture of Ramsden's chain20. Jump up^Cardarelli, Franois Cradarelli (2003).Encyclopaedia of Scientific Units, Weights and Measures. London: Springer. p.41.ISBN978-1-4471-1122-1.