Auto level or automatic level involves an visual device that is utilized to form or confirm marks in the alike straight surface. Surveying is the science of determining relative positions of points or objects on or near the earth's surface. Curvature and Refraction Formula The following formula calculates the vertical angle (in radians): Trigonometric Leveling - Heights and distance problem (Two Exercises) 4. Difference in height (elevation) 3. When calculating the horizontal distance between points, this difference also needs to be taken into consideration. Distance Measurement Introduction Foot-distance from the tip of a man’s big toe to the heel Rod-the sum of the lengths of the left feet of 16 men (16.5 -24 ft.) CIVL 1101 Surveying - Measuring Distance … Distance between 2 points on a plan or map is always horizontal distance irrespective of their elevation, (distance between their projection on horizontal plane). 2. The term stadia comes from the Greek word for a unit of length originally applied in measuring distances for athletic contests. HAND OUT # 1 Engineering Surveying-I Course Instructor: Etikaf Hussain Batch: 2015-16 MEASUREMENT OF HORIZONTAL DISTANCES Page 1 1. Length of Curve (L) – The distance from PC to PT measured along the curve. This distance is called as geodetic distance. Can achieve an accuracy of 1’/3,000’. Today’s electronic total stations all have an opto-electronic distance meter (EDM) and electronic angle scanning. The mean of the distance measured by each level was … K = sighting distance in thousands of feet. Calculating •The distance between marks (titik) can be obtained without using a tape or chain. Measurement of horizontal angles by method of repetition and reiteration. Setout measurement is used to Setout the required point. In practice, this is how ground sampling distance works. Locate the polygon that is to be measured (as directed by your instructor). Use the equation h = √(x 2 + y 2) slope distance = √ [(horizontal distance) 2 + (vertical distance) 2] Step 2. Tradition has it that geometry (literally, earth-measurement) began when the ancient Egyptians had to re-establish boundary lines between fields after the annual floods of the Nile; the United Nations Food and Agriculture Organization still recommends using a (3, 4, 5) triangle to set out right angles in survey work, a procedure that may well go back to the pharaohs. E Vertical distance from VPI to curve e Vertical distance from any point on the curve to the tangent grade K Distance required to achieve a 1 percent change in grade L1 Length of a vertical curve which will pass through a given point D0 Distance from the BVC to the lowest or highest point on curve X Horizontal distance from P' to VPI 1. BASICS OF SURVEYING 1.1 SURVEYING DEFINED Surveying is the art of measuring distances, anglesand positionson or near the surface of the earth. The general formula for variation in temperature correction is as follows: From the above formula, you can deduce that the correction for a 100-ft tape is about 0.00065 ft per 1°F, which is about 0.01 ft for every 15°F change in temperature above or below the standard temperature of 68°F. Step 1. 1. Distance Measurement Electronic distance measuring (EDM) instrument is a major part of total station. This combination makes it possible to determine the coordinates of a reflector by aligning the instrument’s cross hairs on the reflector and simultaneously measuring the vertical and horizontal angles and slope distances. Horizontal distance is measured along a level surface. R Horizontal Length from Angle and Slope Length Calculate the horizontal length (HL) from a slope in degrees and the slope length (SL). •The cost of making a measurement increase with the desired precision of the work. The formula to calculate distance is D=R*S (Distance = Rod Reading Multiplied by the Stadia Constant.) DISTANCE MEASUREMENT Generally, measurements are made horizontally, but on even, often man-made slopes the distance can be measured directly on the slope, but the vertical or zenith angle must be obtained V = Vertical Distance S = Slope Distance H = Horizontal Distance 18 A S V H B C Electronic Distance Measurement. In as per below fig, h is the vertical distance FA’, S is the staff reading on the B.M., θ1 and θ2 are the angles of elevation from the instrument stations O1, and O2 respectively, D is the horizontal distance between O1 and the object, and d is the horizontal distance between the two stations. Measurement of horizontal angles by method of repetition and reiteration. •It is a branch of surveying where horizontal distance and vertical distance can be obtained through stadia line by using teodolite. a) True b) False Answer: a Clarification: Generally, horizontal distances are measured by direct methods, i.e. MEASUREMENT OF HORIZONTAL DISTANCES. This taped distance is represented by s in figure 12-15. INTRODUCTION TO DISTANCE MEASUREMENT HORIZONTAL DISTANCE MEASUREMENT In plane surveying, the distance between two points means the horizontal distance. During the measurement in catenary of a survey line of four bays the following information was obtained: Bay Measured Length (m) Temp C ͦ Difference in level between ends (m) Tension (N) 1 29.899 18.0 +0.064 178 2 29.901 18.0 +0.374 178 3 29.882 18.1-0.232 178 4 29.950 17.9 +0.238 178 The tape has a mass … Also See: Errors in Levelling Survey The difference between the previously inputted data to the instrument（the Setout data）and the measured value can be displayed by measuring the horizontal angle, distance or coordinates of the sighted point. Curvature and Refraction Formula The following formula calculates the vertical angle (in radians): If we assign a value of 1 to each side, bisect the triangle through the base and the vertex, we have a right, 60° triangle with a hypotenuse of 1 and the side adjacent to the 60° angle of 1/2. yyyyy yyyyy yyyyy Horizontal distance = H Vertical distance = V Slope distance = S Ground A B 90º Equation C-3 If the instrument is set over a point whose elevation is known and the heights of the instrument, HI, and subtense bar, HB, are measured, the ground elevation at the subtense bar can be computed from Equation C-4. The horizontal distance measured must be reduced to the distance at sea level. Example 4 - Find the slope distance for the vertical and horizontal distances illustrated in the figure below. Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves. 3. This is necessary because the horizontal distance between two points does not change even if the ground is disturbed. Angle Measuring Measuring distances alone in surveying does not establish the location of an object. It can be measured in millimetres, centimetres, metres, and kilometres in SI unit system and in inches, foot, yard and mile in FPS unit system. laying of chains or tapes on the ground. 2.000 m A B Distance AB= cot 2 where: cot( ) = 1/tan( ) Used for Hydrographic Surveys. Because the total station gives a true slope distance, the horizontal difference is simply H = s * cos α (see figure below). This is done with the help of two special type of instruments- transit theodolite and stadia rod. b) per distance (usually ±1 to ±5 parts per million). bar using a transit: 0°54’13”, and 0°22’20”. The Total station is designed for measuring of slant distances, horizontal and vertical angles and elevations in topographic and geodetic works, tachometric surveys, as well as for solution of application geodetic tasks. Accuracy ratio 1/3000 for distances of 150m or shorter. To accomplish that we need: 1. The survey corrections are calculated using the following formulas. The accuracy of measurement varies from 5 mm to 10 mm per km measurement. The straight (horizontal) length (distance) in the building place is going to be calculated through the utilization of stadia hair. The stadia method, referred to as tacheometry in Europe, is a rapid and efficient way to measure distances in order to locate topographic details. The early EDM instruments could measure long distances with an accuracy of about 5 parts per million (i.e. The term stadia comes from the Greek word for a unit of length originally applied in measuring distances for athletic contests. Alternatively, also by readings of the staff indicated by two fixed stadia wires in the diaphragm (reticle) of the telescope. Given, L = Measured Horizontal Distance; D = Geodetic MSL; h= mean the equivalent of the baseline above the mean sea level. These, then, are used in a variety of combinations in traversing, triangulation, trilateration, mixed-mode operations, mapping, layout staking, leveling, etc. R = correction for refraction. laying of chains or tapes on the ground. Distance measurement. (Ans. 3. LECTURE NOTE COURSE CODE-BCE 206 ENGINEERING SURVEYING. survey is called a stadia traverse. Horizontal distances are measured by direct methods, i.e. 1. A base line of length 100.000 m was first established and divided into 10 equal parts using geodetic means.This was then re-measured with each of the three test levels. Using EDM for short distances is not appropriate, not accurate, because the error is mostly fixed per measurement. However, with the stadia reading a … A1. 1. When the telescope is focused on the rod, the distance s intercepted on the vertically-held rod between two stadia hairs seen in the eyepiece gives the distance D as D = ks, where k, the stadia constant is often made to be 100. It is essential that distances be referenced to the same plane such that … 2. Compute the horizontal distance from the transit to each position of the bar. 2. •It suitable to use in valley, river and area where many survey is called a stadia traverse. Used for Hydrographic Surveys. PART 2 HDM. INTRODUCTION: Measuring the horizontal distance between two points on the surface of earth is one of the most fundamental surveying operations. Correlations for various distances. Here, the distance indicates the horizontal distance amid the two points. You should always measure distances as horizontal distances. Angular direction. Methods For Measuring Distances •Subtense Bar Distances are determined using a theodolite to determine a horizontal angle subtended by two targets precisely spaced at a fixed distance of 2 meters apart on a subtense bar. Trigonometric Leveling - Heights and distance problem (Two Exercises) 4. Direct Method. Magnetic compass measures the angle up to as accuracy of 30’. By Muhammad S A A D Ifrahim. Part 650 Engineering Field Handbook Chapter 1 Surveying 1–viii (210–VI–EFH, October 2008) Figure 1–14 Calculating horizontal latitude and longitude coordinates 1–26 from survey data Figure 1–15 Distance measured as either horizontal or slope distance 1–26 Figure 1–16 Odometer wheel 1–27 Figure 1–17 Breaking chain 1–28 Figure 1–18 Digital laser EDM 1–30 Thus the chaining operations are eliminated. tachymetry: a rapid optical means of measuring distance using a telescope … Same procedure that we used in distance measurement Requires the inclined (slope) distance or horizontal distance between the two points the vertical angle from a horizontal plane V elevation = (sin A) [slope distance (S)] V elevation = (tan A) [horizontal distance (H)] 16 A. S. V. H If the surveyor used slope distances, then the distance between objects and places would change every time the grade changed. 2. A total station is an electronic theodolite and an electronic distance meter ( EDM ). In tachometric surveying, instrument used is known as a tachometer. INTRODUCTION: Measuring the horizontal distance between two points on the surface of earth is one of the most fundamental surveying operations. The EDM records the elapsed time between the wave's emission and its return from the reflector. Tacheometry surveying is defined as the branch of surveying in which horizontal and vertical distances between stations are determined from instrumental observations. In this method, no tape or a chain is used for measuring horizontal distances. This method is very rapid and convenient. The theodolite is left at the BC for the entire curve stakeout if possible, whereas the distance measuring moves continually forward from Curve stakes are set by turning off the deflection angle and measuring the chord distance for the appropriate stations. 10 ft (30 mm) in a ditched highway survey, urban freeway 0.03 ft or (10 mm)). Surveying Multiple Choice Questions on “Tacheometric Surveying – Stadia Method Principle”. The Stadia is a method of measuring distances rapidly with a telescope (usually on an engineer's transit or an alidade) and a graduated rod. Your survey cannot be more accurate than your GSD. Its purpose is to measure vertical and/or horizontal angles. (ii) Multiply the stadia intercept by the reading obtained in (i). By James Rolloque. It is also one of the most basic engineering measurements. Practice making measurements in decimal feet. Study of theodolite in detail - practice for measurement of horizontal and vertical angles. With the help of a tachometer observations (stadia readings and vertical angles) are taken and horizontal and vertical distances are determined by using formulae. Remember: you must measure the horizontal distance! It can be measured by tape or Electronic Distance Measurement (EDM). Equation 7.9 allows Field Work can be completed very rapidly Tacheometry is mainly used for preparing the contour plans of areas. The larger the GSD value, the lower … HEIGHT is always a VERTICAL measurement.LENGTH is always a HORIZONTAL measurement.A2. distances. HORIZONTAL DISTANCE MEASUREMENT. The mean of the distance measured by each level was … The straight (horizontal) length (distance) in the building place is going to be calculated through the utilization of stadia hair. The stadia method, referred to as tacheometry in Europe, is a rapid and efficient way to measure distances in order to locate topographic details. Significant Figures; Errors in Measurement; Propogation of Error; Reliability and Quality of Measurement; Measurement of Horizontal distance . RL at Rod = RL at station + hi + Vertical distance (H) But first we have to find the vertical distance by using trigonometric ratios : We can Use the Tan ratio in order to find the Vertical Distance H Tan α * Horizontal Distance = Vertical Distance Tan ( 53.8) * 600 = 819.79 ft. Now we will find the RL at Point B using the formula stated Above : Tacheometric surveying is a method of angular surveying in which the horizontal distance from the instrument to the staff stations are determined from instrumental observations only. Computed by H = 3.2808 cot (α/2). 5. The correct distance can be calculated from the following formula: or Correct distance × Correct length of chain or tape =Incorrect distance × Incorrect length of chain or tape 3. ±0.1 seconds (good quality theodolite used for geodetic survey) to; ±0.1 minutes (i.e. s α. 126.81 m and 307.86 m) DISTANCE BY TAPING • Most common method of measuring or laying out horizontal distances. The distance measured is always sloping distance from instrument to the object. 2. However, in some activities, vertical height and horizontal distance … Auto level or automatic level involves an visual device that is utilized to form or confirm marks in the alike straight surface. Introduction. horizontal distance. Tangent Distance (T) – The tangent distance is the distance along the tangent (straight line) from PI to PT or PC. There are three main types of horizontal or linear distance measurement. Faculty of Engineering Civil Engineering Department Fifth level (Second Semester. Expressing distances as horizontal measurements. Tacheometry is a branch of angular surveying in which the horizontal and vertical distances are obtained by optical means as opposed to the ordinary process of chain and tape. The vertical distance between the centers of the transit/theodolite and subtense bar can be computed using Equation C-3. 3. METHODS OF MEASURING HORIZONTAL DISTANCES Pacing -- accuracy 1 / 100 (1.0%) •The distance between marks (titik) can be obtained without using a tape or chain. So if I have a survey plat showing courses and distances that depict a measurement of a sloped hill and I want to locate the courses and distances on the earth’s surface of the the sloped hill, I would run my surveyor’s tape from the top of the hill to the bottom of the hill and reduce the actual distance measured as required by the angle of the hill. Engineering Surveying-I Horizontal Distance Measurement and Levelling Problems Q-1. If the points are at different elevations, then the distance is the horizontal length between plumb lines at the points. The method can be utilized using theodolite and tachometer. Refer to the Long Chord (LC) – The straight-line distance from PC to PT. It can be measured … To calculate the multiplying constant k, measure a known distance D1 and take the intercept s1 on the staff kept at that point, the line of sight being horizontal. MEASURING HORIZONTAL DISTANCES 1. In topographical surveys, you measure distances along straight lines. These lines either join two fixed points or run in one direction starting from one fixed point. They are plotted in the field with pegs, pillars or ranging poles. 2. You should always measure distances as horizontal distances. We need to locate the object in 3 dimensions. Methods For Measuring Distances •Subtense Bar Distances are determined using a theodolite to determine a horizontal angle subtended by two targets precisely spaced at a fixed distance of 2 meters apart on a subtense bar. In Surveying all measurements are horizontal, can be inclined; reduce to horizontal and vertical components in plotting. Surveyers find occasions when these two-distance method is very practical and even highly desirable. While accurate, this method is seldom used today. An angle is defined as the difference in direction between two convergent lines. A base line of length 100.000 m was first established and divided into 10 equal parts using geodetic means.This was then re-measured with each of the three test levels. With the Stadia Surveying Instrument focused on the rod, read the measurement markings on the stadia rod shown between the two stadia markings. Direct Measurement of Distance By Wellington Moroka. 21 preloaded basic formula programs useful at civil engineering surveying work. A To determine the horizontal distance (D): (i) Read horizontal scale simultaneously when the vertical scales is read and note the reading by means of the same index α 1. Anyhow a vernier theodolite measures the angles up to and accuracy of 10’’, 20”. The formula for computing the combined effect of curvature and refraction is: C + R = 0.021K 2. In surveying, that undermost circumstances, all distance are presumed to be horizontal distances. Equipments: Steel tape, plumb bob and pins Instructions: 1. Horizontal length (distance) 2. Measuring Elevation Elevation refers to the height above or below a fixed ... the line of sight of the telescope horizontal Differential Leveling Level Instrument CIVL 1101 Surveying - Introduction to Differential Leveling 2/7. you can fix the horizontal distance CB at 100 m, which will give you S% = AC directly in metres; you can fix the horizontal distance CB at 10 m instead, which will give you S% = 10 AC in metres. Whether on sloping or level ground, it is horizontal distances that must be measured. 2. Computed by H = 3.2808 cot (α/2). Introduction. Most surveying Instruments have a Stadia constant of “100”. Study of theodolite in detail - practice for measurement of horizontal and vertical angles. Introduction to surveying and Mapping . establish a survey plan that includes checks on accuracy, e.g. From the study of geometry, it is evident that a point can be located by measuring only the distance from two known points. CORRECTING FOR SLOPE.— When you take a measurement with a tape along an inclined plane (along the natural slope of the ground), obviously, the taped distance is greater than the horizontal distance. 6 seconds—typical theodolite). A 7-degree horizontal curve covers an angle of 63o15’34”. Traverse distances are usually measured with a surveyor's tape or by EDM, but also may sometimes be measured by stadia, subtense, or trig-traverse. PART III: Basic Survey Observations 3.1. If you press the button under the triangle (next to MEAS) the line will move around and the display will read the vertical distance and then the hypotenuse before going back to the horizontal distance. The horizontal distance is inferred from the vertical angle included between two well-defined points on the staff and the known vertical distance between them. Surveyors are concerned with the measurement of vertical and horizontal distances and angles and, even more recently, with direct positioning. Use a steel tape & plumb bob to measure horizontal distances. At every point along that length, the line tangent to the level surface is horizontal. •It is a branch of surveying where horizontal distance and vertical distance can be obtained through stadia line by using teodolite. In this method, no tape or a chain is used for measuring horizontal distances. distance meter (distancer), and so it can measure angles and distances at the same time. The distance between these points is needed. There’re 2 points on earth surface (point A and point B). This is done with the help of two special type of instruments- transit theodolite and stadia rod. Record the horizontal angle (H.ANG), the horizontal distance and (if you are measuring heights) the vertical distance. To calculate slope distance, you will need a basic scientific calculator with a square root (√z ) function. 1. It is of either transit or non-transit type. EDM is commonly carried out with digital instruments called theodolites. Construction Surveying Lab: Horizontal Distance MeasurementThe lab activity is recorded on the ECU campus as part of CMGT 2951. Theodolite is more precise than magnetic compass. Horizontal Distance One of the most basic surveying operations is the measurement of distance. One crew member shall be responsible for taking notes in the field book. ±5 mm for every km or to ±150 mm over a 30 km line). DISTANCE MEASUREMENT In plane surveying, the distance between two points means the horizontal distance. Theodolite is a telescope mounted on horizontal and vertical protractors. Calculator uses the cosine function " The cosine of an angle in a right angled triangle is the ratio that multiplies the slope length and results in the horizontal length. The side opposite then is 3/4 or 0.8660 and the trig functions are: sin 60° = 3 4 /1 = 3/4 = 0.8660 1. Its range varies from 2.8 km to 4.2 km. H . If the points are at different elevation, the distance is the horizontal length between vertical lines at the points. Tacheometry is a branch of angular surveying in which the horizontal and vertical distances are obtained by optical means as opposed to the ordinary process of chain and tape. targets is measured using the theodolite to determine the distance to the bar center and hence the distance AB. Surveying and geometry. •It suitable to use in valley, river and area where many In this research, three levels: the optical levels NA2 and N3 from Leica and the digital level SDL30 from Sokkia were subjected to distance measurement accuracy test. Where C = correction for curvature. Try to keep the distance to the BS and the FS equal Provide the rodpersonwith a level for the rod Calculating point elevations from the vertical distance components (supplemented with keyboard input of instrument and reflector heights). Computing coordinates of survey points from horizontal angle and horizontal distance. Averages multiple angle measurements. Averages multiple distance measurements. Computes horizontal and vertical distances. INTRODUCTION •Tachymetry word is derived from the Greek takhus metron meaning ‘swift measurement’. In this research, three levels: the optical levels NA2 and N3 from Leica and the digital level SDL30 from Sokkia were subjected to distance measurement accuracy test. If you need to measure objects within an inch of actual size, you will want 0.5-inch GSD or lower. Because only a surveyor who has full understanding of surveying techniques will be able to determine the most efficient methods required to obtain optimal results over a wide variety of surveying problems. Determine the radius, the length of the curve, and the distance from the circle to the chord M. Solution to Example 7.5 Rearranging Equation 7.8,with D = 7 degrees, the curve’s radius R can be computed. HORIZONTAL CURVE TERMINOLOGY Symbol Terminology Equation LC Long Chord 2R sin ∆ 2 R Radius OA = OB = OC L Length of Curve L = 0.0174533 R ∆ T Tangent Distance T = AV = R tan ∆ 2 D Degree of Curve D = 5729.578 R E External Distance E = BV = R cos ∆ 2 - R MO Middle Ordinate MO = R(1 - cos ∆ 2 ) ∆ Central Angle AOC Introduction to Surveying; Fundamentals of Mapping; Overview of Surveying and Indian Topographic Map; Measurements and Errors . Simple odometer used to measure distance. Methods. The survey corrections are calculated using the following formulas. Using the equation, D1 = ks1 + C or k = For average value, staff intercepts, s2, s3 etc., can be measured corresponding to distance D2, D3 etc., and mean value can be calculated. Electronic distance measuring equipment has a precision of -/+ 0.04 ft (instrument constant), -/+ 1:300,000 of length measured. They are used with automatic target recognizer. Click here to download programs. Heights and distance using Principles of tacheometric surveying (Two Exercises) 5. You may have to measure on ground which has no slope, or only a very small slope that is less than or equal to 5 percent (see Section 4.0). INTRODUCTION •Tachymetry word is derived from the Greek takhus metron meaning ‘swift measurement’. It has been used in the past for precise government surveys and is now becoming more common for land development and very precise construction work . This will give correction to be subtracted from the distance (100 S) obtained from the stadia intercept. A Theodolite is a measuring instrument used to measure the horizontal and vertical angles. Calculate the horizontal distance to a staff and relative elevation from measured values using stadia surveying. In order to find the distance, we just set the instrument at one of these points in the graduated staff rod. Can achieve an accuracy of 1’/3,000’. METHOD OF DETERMINING DISTANCE •The horizontal or linear distance between two points is the distance between the plumb line through the points. ( 0. Measurements by optical means In this method, observations are taken through a telescope, and calculations are done for distances such as in tachometer (stadia) or in triangulation. Tachometer (stadia is the common term in the USA) is a surveying method utilized to quickly determine the horizontal distance to, and elevation of, a point. Optical Method. Precision depends on the type and is usually from. The Total station is designed for measuring of slant distances, horizontal and vertical angles and elevations in topographic and geodetic works, tachometric surveys, as well as for solution of application geodetic tasks. Tacheometry surveying is defined as the branch of surveying in which horizontal and vertical distances between stations are determined from instrumental observations. Distance Measurement Introduction Foot-distance from the tip of a man’s big toe to the heel Rod-the sum of the lengths of the left feet of 16 men (16.5 -24 ft.) CIVL 1101 Surveying - Measuring Distance 1/6 A true horizontal distance is actually curved, like the surface of the earth. Heights and distance using Principles of tacheometric surveying (Two Exercises) 5. Correction for Absolute Length: - It is the usual practice to express the absolute length of a tape as … By Zerah Arlando. To measure the horizontal distance between two points, one surveyor uses an EDM instrument to shoot an energy wave toward a reflector held by the second surveyor. It is also one of the most basic engineering measurements. redundant points, pacing of measured distances, surveying between fixed positions, etc.
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