Chapter 3 surveying equipment, measurements and errors. Unlike the approaches reported in the literature, the method does. Unit 6 angular measuring devices angular measuring. The instruments of this measurements is described in this ppt. Angular velocity nonlinear observer from vector measurements. It is also known as the compass rule and is most commonly used in traverse adjustment. This is most suitably adapted to small plane areas with very few details. The dimensions to be measured are aligned with the graduations of the scale. Landis markley nasa goddard space flight center, greenbelt, md 20771 yang cheng university at bu. This article includes the definition of traverse surveying along with its classification, errors in traversing, checks, the completed method of traversing and plotting of traverse survey. We propose a technique for estimating the angular velocity of a rigid body and the torque applied to it, from vector measurements.
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. Chapter 3 surveying equipment, measurements and errors wsdot. The least count of a measuring instrument is the smallest change in the measured quantity that can be. Pdf accuracy of linear and angular measurements on panoramic. Linear measurement is the basis of all surveying and even through angles may be read precisely, the length of at least one line in tract must be measured to supplement the angles in locating points. Dimensions a very common measurement is that of dimensions, i. Distances, angles, directions, locations, elevations, areas, and volumes are thus determined from the data of the survey. Survey definition, to take a general or comprehensive view of or appraise, as a situation, area of study, etc. The measurement type can be divided as, direct measurement method, optical measurement method and. It consists essentially of a sighting tube in form of a telescope, an horizontal and vertical scales, which are so set that horizontal and vertical angles of the object sighted in the telescope can be read from the scale see fig. There are two principal measurements in surveying works.
This method is very accurate compared to other methods. Types of measurements in surveying civil engineering. Survey data is portrayed graphically by the construction of maps, profiles, cross. Along with the actual survey measurements are the mathematical calculations. In the metric system, millimeters, centimeters, meters and kilometers, are used to measure linear measurements. Without taking a survey of the plot where the construction is to be carried out, the work cannot begin 2.
The following additional operations are carried out to obtain the necessary qualities in slip gauges during manufacture. Chain surveying definition, details, procedure civil. Measurement of horizontal distances or measuring linear measurement is required in chain surveying, traverse surveying and other types of surveying. Lineartaper pots are the most commonly available, and are widely used in sensing and control. May 06, 2018 angular measurements mean measurement of angles made either directly or indirectly by using some instruments. The steel highway tape has graduations every foot, and only the end foot is graduated in tenths and hundredths of a foot. Chapter direct linear measurements and field survey safety. Some of the typical measurements are tapers of bores, flank angle and included angle of a gear, angle made by a seating surface of a jig with respect to a reference surface, taper angle of a jib and so on. Now we will go on with the discussion of each of these types of measurements along with their. Linear and angular head acceleration measurements in. Syllabus definition of metrology linear measuring instruments. Land surveying chapter 3 linear survey, measurement free download as powerpoint presentation.
What are the considerations while manufacturing the slip gauges. In chain survey, only measurements are taken in the field, and the rest work, such as plotting calculation etc. Sometimes, the primary objective of angle measurement is not to measure angles. An operators manual is furnished with each new instrument. Types, properties, uses and details of these surveying equipment is discussed. The mean angle is then equal to the sum of the total angle divided by the number of observations. Land surveying chapter 3 linear survey, measurement. In the case of theodolite traversing, the linear measurements are done by using chain or stadia method and angular measurements are done by theodolite. Note that a pot with a linear taper should not be confused with a linearmotion pot, which is sometimes called a linear pot. Here horizontal angular measurements are made using magnetic compass with the linear measurements made using the chain or tape. Linear measurement applies to measurement of lengths, diameter, heights and thickness including external and internal measurements. Accuracy is the degree of conformity of a given measurement with a standard value. Basic field operations performed by a surveyor involve linear and angular measurements.
Generally used when high accuracy is not required ii compass surveying horizontal angles are measured with a compass in addition to linear measurements with a chain or tape. A linear measurement on the horizontal plane determines the horizontal. Distance between 2 points on a plan or map is always horizontal distance irrespective of their elevation,distance between their projection on horizontal plane. Knowing the interior angles and the baseline length, the trigonometric law of sines can then be used to calculate the lengths of any other side. Some commonly used face standard angular measuring devices are. This is a quick survey carried out in the field with the measurements and drawings made at the same time using a plane.
Aug 29, 2015 the general principles of surveying are. Survey data is portrayed graphically by the construction of maps, profiles, cross sections, and diagrams. Among the variety of instruments that are available to measure angles and elevations, it is important to choose the best one that is more suitable for the specific job. Often widely using measurements are linear measurement angular measurement dimensions. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. A survey of nonlinear attitude estimation methods john l. These two measurements enable the survey team to calculate position b as in an open traverse. Relationships between linear and angular motion body segment rotations combine to produce linear motion of the whole body or of a specific point on a body segment or implement joint rotations create forces on the pedals. Twoyear cosmology large angular scale surveyor class. Types of measurements in surveying civil engineering projects.
Gaussian pdf between measurements and bayes formula1,2 to incorporate measurement information. Without taking a survey of the plot where the construction is to be carried out, the work cannot begin. According to the first principle, the whole area is first enclosed by main stations i. Measuring the dimensions of objects in a detail survey, such as the width of a path. Principles and methods of surveying in civil engineering. Surveying instruments for angle and elevation measurements. Factors which influence the use of offset tape measured distances are limited to the length of the tape, usually 2 or 5 meters. Forces on pedals rotate crank which rotates gears which rotate wheels. Linear and angular head acceleration measurements in collegiate football each year, between 1. It is used when the angular and linear measurements are equally precise. This chapter deals with devices such as protractors, sine bars, angle gauges, spirit levels, and other optical instruments used for angular measurements. It will give accuracy up to the smallest division of the main scale. Make sure you measure the hd, not sd, because you cannot assume the ground is level. In other words, keep the offsets in line, caused by errors in angular measurements, approximately equal to the errors in linear measurements.
Linear measuring devices and comparators if the smallest unit in the main scale be 0. The two main principles used in an autocollimator are a the projection and the refraction of a parallel beam of light by a lens, and b the change in direction of a reflected angle on a plane reflecting surface with change in angle. Adjustment of a closed traverse theodolite surveying. In this video we can know the linear and angular measurement. Let the smallest main scale reading, that is the distance between two consecutive graduations also called its pitch be s and the distance between two consecutive vernier scale graduations be v. Chapter direct linear measurements and field survey safety topics 1 1. Edm g2 upgrade by gerald bennet types of displacement and angle sensors advantages of capacitive displacement sensors readout methods limits to sensitivity. Longer tapes of 200 and 300 ft are common for some contracts. However, measurements of certain components requires some mechanical means to either hold the measuring device steadily against the component being measured or to capture the reading, which could be read at leisure later. Vernier, micrometer and interval measurement slip gauges and. Using theodolite, the magnetic bearing of the first traverse line is measured and from that magnetic bearing of other sides are calculated.
Pdf assessment of linear and angular measurements on. How are these measured and which instrument should i use. Chapter 4 linear and angular measurement measurement. Proper care in the use, storage, transportation and adjustment of the equipment is a major factor in the successful completion of a survey. Linear and angular measurements of computergenerated models. The high number of concussions in football provides a unique opportunity to collect biomechanical data to characterize mild traumatic. Angular measurements refer to the magnetic bearing or horizontal angle taken by a prismatic compass or theodolite. When the vertical angle is applied to the slope distance, the horizontal and vertical distances may be calculated.
The unit is practical and provides opportunities for learners to carry out realistic surveying tasks and produce. Other units include the foot, the inch, the yard, the mile, etc. Precision is the extent to which a given set of measurements agree with their mean. So, it is necessary to measure linear measurement length and angular measurement direction or horizontal angle of a survey line. In chain surveying, the linear measurements are taken by chain or tape. Surveying is the art of making suitable measurements in horizontal or vertical planes. If the dimension is less or greater, than the standard, then the difference will be shown on the dial. Linear and angular measurement interview question and.
Pdf the accuracy of measurement of tooth length and angulation on dental panoramic tomograms dpts is thought to be highly dependent on head. Measure the horizontal angle and distance between the two adjacent points. Mar 11, 2015 the instruments of this measurements is described in this ppt. In this ppt according to be syllabus linear and angular measurement is try to describe. Surveying surveying principles and methods in civil engineering surveying principles and methods in civil engineering surveying is the process of determining relative positions of different objects on the surface of the earth by measuring horizontal distances between them and preparing a map to any suitable scale. Linear measurement types, instruments and common errors. Accuracy and precision accuracy and precision are two different, yet equally important surveying concepts. It gives only the difference between actual and standard dimension of the workpiece. To assist in recovering the station, the surveyor drives a reference witness stake into the ground so that it slopes toward the station. Also, pairwise comparison of positions was calculated using the least significant difference lsd test for multiple comparisons. These measurements usually are not as complex as area or volume measurements, but there are some things you should know about properly performing and recording the measurements. Unit 2 linear and angular measurement authorstream presentation.
It is an indirect type of instrument and used for linear measurement. Chapter 5 deals with coordinate systems and reference datums necessary for an understanding of satellite position fixing and an. We report circular polarization measurements from the first two years of observation with the 40 ghz polarimeter of the cosmology large angular scale surveyor class. A survey may require vertical measurement in addition to linear and angular. In surveying all measurements are horizontal, can be inclined. The steel highway tape is generally used for the direct linear measurement of important survey lines. The fact that not all measurands can be measured by linear methods stresses the significance of this topic. The measurements are done with respect to two faces of the measuring instruments. This is one of the important subjects of civil engineering. The line measuring instruments have series of accurately spaced lines marked on them e. Unit 5 linear measuring devices and linear measuring. Linear measurement can be achieved by various instruments. Traverse surveying definition, types, methods, checks. Linear and angular measurement metrology interview question and answers linear and angular measurement metrology interview, viva, oral question and answers 1.
During measurements, it is impossible to set out all the chain lines in a straightforward method. Linear measurements refer to horizontal distances measured by chain or tape. The changes in the angular and linear measurements on panoramic radiographs taken at different positions were evaluated using repeated measures analysis of variance anova. Traverse surveying is a popular method of surveying. Linear and angular measurements were performed using a cmm machine, the software package, and a dial caliper or. The distance between the fulcrum roller centre and. To survey an area by chain survey across obstacles and to calculate the obstructed lengths by using different methods. It is a visual aid that allows the user to measure more precisely than could be done unaided when reading a uniformly divided straight or circular measurement scale. From the above definition, we conclude on two types of measurements in surveying. Consistency when a survey involves both angular and linear measurements, maintain consistency if practicable between the precision of angular measurements and that of the linear measurements.
Face standard angular measuring devices include angle gauges and sine bars. In chain surveying, the positions of main stations and directions of main survey lines are fixed by tie lines and check lines. There are various surveying instruments for measurement of angles and elevations. Unit 6 angular measuring devices angular measuring devices. Measurements in land surveying types of measurement. Precision obtained in such instruments is more than the precision obtained in line standard angular measuring devices. It is the art of measuring horizontal and vertical distances between objects, of measuring angles between lines, of determining the direction of lines, and of establishing points by predetermined angular and linear measurements. It is the di erence between the value of one main scale division and the value of one vernier scale division. The measurement of this linear horizontal distance between two points on the earth surface is known as linear measurement.
In this video, i have covered the topic methods of linear measurements and chain with its types if you like this video plz like, share and subscribe. Decimal fractions of the meter are also used when accuracy is required. Precise measurements of small linear and angular displacements with capacitance methods sergio rescia motivation. To locate a new station by at least two measurements linear or angular from fixed reference points. Linear measurements the determination of the distance between two points on the surface of the earth is one of the basic operation of surveying. Linear and angular measurement the linear measurement includes measurements of length, diameters, heights and thickness the angular measurement includes the. May 2005 surveying equipment, measurements and errors 3. Aug 15, 20 linear measurements the determination of the distance between two points on the surface of the earth is one of the basic operation of surveying. Procedures the directional method will be used exclusively for the control survey. This chapter covers a broad range of linear measurement instruments from a simple steel rule up to digital calipers and micrometers. Linear measurement in engineering survey, the linear horizontal distance is to be measured to complete a survey. Survey methods used for tapes are used for the measurement of linear distance. Each person will set up and run the instrument for at least one point of the traverse.
The following rules may be used for finding the corrections to balance the survey. Chapter 4 linear and angular measurement free download as pdf file. The surveyors next measure the interior angles cab, abc, and bca at point a, b, and c. Vertical angular measurements are measured to determine slope of survey lines from the horizontal plane level line. The theodolite is the basic instrument for measuring horizontal and vertical angles. The measurement type can be divided as, direct measurement method, optical measurement.