Embedded Files
LEC: Apply the basic surveying concepts, principles and theories on distance, angular measurements and area computation.
LAB: Define the importance of various team members’ roles and cite examples of team behaviors that are helpful in the implementation of the fieldwork exercise.
MODULE 1: PACING AND TAPING
OVERVIEW
This module introduces the basic concepts, principles and theories of surveying. Procedure of proper pacing and taping over level and sloping ground will be discussed. Most of the allocated time will be dedicated to solve problems applying corrections to the original measurements to determine correct and more accurate lengths.
This module introduces the basic concepts, principles and theories of surveying. Procedure of proper pacing and taping over level and sloping ground will be discussed. Most of the allocated time will be dedicated to solve problems applying corrections to the original measurements to determine correct and more accurate lengths.
LEARNING OBJECTIVES:
At the end of this module, you should be able to: 1. Apply the basic surveying concepts, principles, and theories on distance computation. 2. Solve for distances from a provided set of survey data.
At the end of this module, you should be able to: 1. Apply the basic surveying concepts, principles, and theories on distance computation. 2. Solve for distances from a provided set of survey data.
1.1 INTRODUCTION TO SURVEYING
According to Rayner and Schmidt, surveying is the art of determining the positions of points on or near the earth's surface by means of measurements in the three elements of space; namely, distance, direction, and elevation. Meanwhile, if I were asked about the definition of surveying, I would literally say "it is the measurement of horizontal and vertical distances, directions, and angles of relative positions on the earth's surface".
According to Rayner and Schmidt, surveying is the art of determining the positions of points on or near the earth's surface by means of measurements in the three elements of space; namely, distance, direction, and elevation. Meanwhile, if I were asked about the definition of surveying, I would literally say "it is the measurement of horizontal and vertical distances, directions, and angles of relative positions on the earth's surface".
TWO GENERAL CLASSIFICATIONS OF SURVEYING
The two general classifications of surveying are plane surveying and geodetic surveying. Plane surveying is the surveying that considers the earth to be a flat surface while geodetic surveying is the surveying that considers the curvature shape of the earth.
The two general classifications of surveying are plane surveying and geodetic surveying. Plane surveying is the surveying that considers the earth to be a flat surface while geodetic surveying is the surveying that considers the curvature shape of the earth.
1.2 TYPES OF SURVEYING
The different types of surveys depends on the location where the survey is conducted, and the purpose of the survey. I actually created a mnemonic to easily familiarize the ten types of surveys which is 3C-F-HIM-PRT. Cadastral Surveys are surveys conducted in urban and rural locations while city surveys are those conducted in cities. Both of these aim to determine boundaries, property lines and plan for improvements or expansion. Construction surveys are the surveys conducted in construction sites with the purpose of gathering data about dimensions, ground configurations, dimensions, and elevations; whereas, forestry surveys are those conducted in forest lands for forest management and conservation. Furthermore, hydrographic surveys, from the word hydro, are those surveys conducted in bodies of water such as lakes, oceans, and streams for the purpose of mapping shore lines, measuring flow of streams, developing water supplies, and many more; industrial surveys are used in ship building, construction of aircraft, layout of complex machinery and in other industries; while mine surveys are used in underground excavations and surface mine structures to determine geological formations, calculate excavated volumes, and for other related mining works. Moreover, photogrammetric surveys are surveys which measurements are obtained from photographs especially if ground surveys cannot be done. Route surveys are surveys conducted to determine the route of a proposed highway, railroads, pipelines, and other linear projects, while topographic surveys are surveys conducted to locate natural and artificial features such as hills, mountains, rivers, and lakes.
The different types of surveys depends on the location where the survey is conducted, and the purpose of the survey. I actually created a mnemonic to easily familiarize the ten types of surveys which is 3C-F-HIM-PRT. Cadastral Surveys are surveys conducted in urban and rural locations while city surveys are those conducted in cities. Both of these aim to determine boundaries, property lines and plan for improvements or expansion. Construction surveys are the surveys conducted in construction sites with the purpose of gathering data about dimensions, ground configurations, dimensions, and elevations; whereas, forestry surveys are those conducted in forest lands for forest management and conservation. Furthermore, hydrographic surveys, from the word hydro, are those surveys conducted in bodies of water such as lakes, oceans, and streams for the purpose of mapping shore lines, measuring flow of streams, developing water supplies, and many more; industrial surveys are used in ship building, construction of aircraft, layout of complex machinery and in other industries; while mine surveys are used in underground excavations and surface mine structures to determine geological formations, calculate excavated volumes, and for other related mining works. Moreover, photogrammetric surveys are surveys which measurements are obtained from photographs especially if ground surveys cannot be done. Route surveys are surveys conducted to determine the route of a proposed highway, railroads, pipelines, and other linear projects, while topographic surveys are surveys conducted to locate natural and artificial features such as hills, mountains, rivers, and lakes.
1.3 MEASUREMENT OF DISTANCE AND ERRORS IN MEASURMENT PART 1
To measure is to determine the size, length, weight, capacity, or dimensions of something. There are two types of measurement, direct and indirect measurement. Direct measurement is measuring exactly the target needed to be measured by using a standard measuring unit such as a measuring tape; whereas, indirect measurement is measuring something by comparison to other things of known measurement. In surveying, measurements commonly involve conversions such as when reading the graduates on a range rod. Some common conversions involve: 1 decimeter is equal to 10 centimeters, 1 meter is equal to 10 decimeters or 100 centimeters, and 1 kilometer is equal to 1000 meters. In order to easily memorize these metric conversions, a number line is shown on the right which summarizes all the conversions in meters.
To measure is to determine the size, length, weight, capacity, or dimensions of something. There are two types of measurement, direct and indirect measurement. Direct measurement is measuring exactly the target needed to be measured by using a standard measuring unit such as a measuring tape; whereas, indirect measurement is measuring something by comparison to other things of known measurement. In surveying, measurements commonly involve conversions such as when reading the graduates on a range rod. Some common conversions involve: 1 decimeter is equal to 10 centimeters, 1 meter is equal to 10 decimeters or 100 centimeters, and 1 kilometer is equal to 1000 meters. In order to easily memorize these metric conversions, a number line is shown on the right which summarizes all the conversions in meters.
ERRORS VS. MISTAKES
Another thing I learned in this course is that error is different from mistake. When we say mistake, it is the inaccuracy in measurement because of the surveyor's carelessness, or improper execution, while error is the difference between the theoretical or true value and the measured or experimental value.
Another thing I learned in this course is that error is different from mistake. When we say mistake, it is the inaccuracy in measurement because of the surveyor's carelessness, or improper execution, while error is the difference between the theoretical or true value and the measured or experimental value.
TYPES OF ERRORS
There are mainly two types of errors: the systematic and accidental error. Systematic error or cumulative error is the error that for constant condition, remains the same as to sign and magnitude. In other words, systematic errors follow a system when they occur and have the same nature. On the other hand, accidental error or random error is the error whose sign and magnitude is just an accident and beyond the control of the surveyor. In other words, it occurs accidentally and can of any nature positive or negative.
There are mainly two types of errors: the systematic and accidental error. Systematic error or cumulative error is the error that for constant condition, remains the same as to sign and magnitude. In other words, systematic errors follow a system when they occur and have the same nature. On the other hand, accidental error or random error is the error whose sign and magnitude is just an accident and beyond the control of the surveyor. In other words, it occurs accidentally and can of any nature positive or negative.
SOURCE OF ERRORS
There are three sources of errors. When the error is caused by the imperfections of the instruments such as using a steel tape with incorrect tape length, the error is called an instrumental error. When the error is caused by the surrounding environment such as reading the magnetic needle incorrectly due to magnetic declination, the error is called a natural error. Lastly, when the error is caused by the limitations of the human senses such as reading a rod which is out of plumb during sighting, the error is called a personal error.
There are three sources of errors. When the error is caused by the imperfections of the instruments such as using a steel tape with incorrect tape length, the error is called an instrumental error. When the error is caused by the surrounding environment such as reading the magnetic needle incorrectly due to magnetic declination, the error is called a natural error. Lastly, when the error is caused by the limitations of the human senses such as reading a rod which is out of plumb during sighting, the error is called a personal error.
ACCURACY VS. PRECISION
Accuracy and precision are two different things. Accuracy is the degree of closeness of the measurements to the target or reference value. In other words, it shows how close the measurements are to the absolute value. On the other hand, precision is the degree of closeness of the measurements with each other. Simply, it indicates how consistent the measurements are made. Shown on the right are four dart boards with the center as the reference or absolute value while the x marks are the measurements. When the x marks are separate with each other and at the same time far from the center, it is not accurate and not precise. When the x marks are close with each other but far from the target, it is precise but not accurate. Furthermore, when the x marks are on the target but are far from each other, then it is accurate but not precise. Finally, when the x marks are both close to each other and are on the target, it is accurate and precise.
Accuracy and precision are two different things. Accuracy is the degree of closeness of the measurements to the target or reference value. In other words, it shows how close the measurements are to the absolute value. On the other hand, precision is the degree of closeness of the measurements with each other. Simply, it indicates how consistent the measurements are made. Shown on the right are four dart boards with the center as the reference or absolute value while the x marks are the measurements. When the x marks are separate with each other and at the same time far from the center, it is not accurate and not precise. When the x marks are close with each other but far from the target, it is precise but not accurate. Furthermore, when the x marks are on the target but are far from each other, then it is accurate but not precise. Finally, when the x marks are both close to each other and are on the target, it is accurate and precise.
THEORY OF PROBABILITY
Various types of investigations show that the occurrence of accidental or random errors follow the theory of probability. When we say probability, it is the likelihood that an event will happen. The theory of probability is based upon the following assumptions relative to the occurrences of errors:1. Small errors tend to be more frequent than large ones, thus, they are most probable.2. On the other hand, large errors occur infrequently and are less probable.3. Positive and negative errors of the same size happen with equal frequency, that is, they are equally probable.4. The mean of an infinite number of observations is the most probable value.
Various types of investigations show that the occurrence of accidental or random errors follow the theory of probability. When we say probability, it is the likelihood that an event will happen. The theory of probability is based upon the following assumptions relative to the occurrences of errors:1. Small errors tend to be more frequent than large ones, thus, they are most probable.2. On the other hand, large errors occur infrequently and are less probable.3. Positive and negative errors of the same size happen with equal frequency, that is, they are equally probable.4. The mean of an infinite number of observations is the most probable value.
MOST PROBABLE VALUE
The most probable value of a group of repeated measurements is the arithmetic mean or average. It is also considered as the quantity which has more chances of being correct than any other. Shown on the right is a sample problem that would be used for the following topics. The letter a question asked for the most probable value (mpv) of the measured length. As you can see in my solution, I just computed the average (mpv = ∑x/n) of the given measurements to get the most probable value which is 1000.45m.
The most probable value of a group of repeated measurements is the arithmetic mean or average. It is also considered as the quantity which has more chances of being correct than any other. Shown on the right is a sample problem that would be used for the following topics. The letter a question asked for the most probable value (mpv) of the measured length. As you can see in my solution, I just computed the average (mpv = ∑x/n) of the given measurements to get the most probable value which is 1000.45m.
RESIDUAL AND PROBABLE ERROR
Residual is simply the difference between any measured value of a quantity and its most probable value while probable error is a quantity which, when added to and subtracted from the most probable value, defines a range within which there is a 50% chance that the true value of the measured quantity lies inside (or outside) the limits thus set. The letter b of the previous problem asked for the probable error of the single measurement (PEs) and the probable error of the mean (PEm). If you observe my solution, I first used the residual to obtain the needed ∑v2 in the formula of the probable error. Further, to get the final expression for the most probable length, I just used the probable error of the mean to be added/subtracted from the most probable value.
Residual is simply the difference between any measured value of a quantity and its most probable value while probable error is a quantity which, when added to and subtracted from the most probable value, defines a range within which there is a 50% chance that the true value of the measured quantity lies inside (or outside) the limits thus set. The letter b of the previous problem asked for the probable error of the single measurement (PEs) and the probable error of the mean (PEm). If you observe my solution, I first used the residual to obtain the needed ∑v2 in the formula of the probable error. Further, to get the final expression for the most probable length, I just used the probable error of the mean to be added/subtracted from the most probable value.
RELATIVE PRECISION
Relative precision or relative error is the uncertainty of a measurement compared to the size of the measurement that is the absolute error divided by the magnitude of the exact value. In other words, it is the ratio of the magnitude of the error to the magnitude of the most probable value. That is why, in order to get the relative precision in the sample problem, I just divided the probable error by the mpv. Note that there is a separate relative precision for the single measurement and the mean and that the numerator should be reduced to unity or 1.
Relative precision or relative error is the uncertainty of a measurement compared to the size of the measurement that is the absolute error divided by the magnitude of the exact value. In other words, it is the ratio of the magnitude of the error to the magnitude of the most probable value. That is why, in order to get the relative precision in the sample problem, I just divided the probable error by the mpv. Note that there is a separate relative precision for the single measurement and the mean and that the numerator should be reduced to unity or 1.
WEIGHTED OBSERVATIONS
It is evident that some observations are more precise than the others, thus adjustment is needed. In adjusting the observations, it is desirable to assign relative weights to individual observations. The observation that is more precise should be weighted more heavily. Note that weights are inversely proportional to the square of the probable errors. I used this highlighted idea to get the answer in the problem on the left. As you can see, the first thing I did is squared the probable errors and determined their weights by getting the reciprocal of the squared errors. Then, to determine the relative weights, I picked the lowest value to be divided to all the weights I recently computed. For instance, the lowest value is 1736. I divided all the weights to this number such as 27778 divided by 1736 is 16. Further, I multiplied the given elevations to their corresponding relative weights to ultimately determine the total elevation. Finally, I divided the total elevation by the relative weight to determine the most probable value of the elevation of the point which is 219.847m.
It is evident that some observations are more precise than the others, thus adjustment is needed. In adjusting the observations, it is desirable to assign relative weights to individual observations. The observation that is more precise should be weighted more heavily. Note that weights are inversely proportional to the square of the probable errors. I used this highlighted idea to get the answer in the problem on the left. As you can see, the first thing I did is squared the probable errors and determined their weights by getting the reciprocal of the squared errors. Then, to determine the relative weights, I picked the lowest value to be divided to all the weights I recently computed. For instance, the lowest value is 1736. I divided all the weights to this number such as 27778 divided by 1736 is 16. Further, I multiplied the given elevations to their corresponding relative weights to ultimately determine the total elevation. Finally, I divided the total elevation by the relative weight to determine the most probable value of the elevation of the point which is 219.847m.
INTERRELATIONSHIP OF ERRORS
A. SUMMATION OF ERRORS.
If several measured quantities are added, each of which is affected by accidental errors, the probable error of the sum is given by the square root of the sum of the squares of the separate probable errors arising from the several sources. Shown on the right is an sample problem I got from my classwork assignment. As stated, I was able to determine the probable error in the problem by getting the square root of the sum of the squares of the errors. Then, to get the most probable value of the perimeter, I first computed the perimeter by adding the given measurements without the errors. Finally, I just combined the calculated perimeter to the calculated sum of the errors.
A. SUMMATION OF ERRORS.
If several measured quantities are added, each of which is affected by accidental errors, the probable error of the sum is given by the square root of the sum of the squares of the separate probable errors arising from the several sources. Shown on the right is an sample problem I got from my classwork assignment. As stated, I was able to determine the probable error in the problem by getting the square root of the sum of the squares of the errors. Then, to get the most probable value of the perimeter, I first computed the perimeter by adding the given measurements without the errors. Finally, I just combined the calculated perimeter to the calculated sum of the errors.
B. PRODUCTS OF ERRORS
For a measured quantity which is determined as the product of two other independently measured quantities with their corresponding probable errors, the probable error of the product is given by the equation: PEp = ±√[(Q1 x PE2)2 + (Q2 x PE1)2]. By reading the problem on the right that I got from my classwork assignment, it can be inferred that the probable error of the product is what we are looking for since it first asked to determine the area. The area of a triangle is ½ b x h and by following the given formula for error, I obtained the probable error of ±13.661m2. Note that I forgot the sign ± that is why it has only one check.
For a measured quantity which is determined as the product of two other independently measured quantities with their corresponding probable errors, the probable error of the product is given by the equation: PEp = ±√[(Q1 x PE2)2 + (Q2 x PE1)2]. By reading the problem on the right that I got from my classwork assignment, it can be inferred that the probable error of the product is what we are looking for since it first asked to determine the area. The area of a triangle is ½ b x h and by following the given formula for error, I obtained the probable error of ±13.661m2. Note that I forgot the sign ± that is why it has only one check.
1.4 MEASUREMENT OF DISTANCE AND ERRORS IN MEASUREMENT PART 2
CORRECTIONS IN TAPING
Taping is the linear measurement of the horizontal distance between two points using a surveyor's tape. The purpose of taping operations could either be to determine an unknown length or to lay out a required specified length. Corrections to taping are applied by using the summarized rules shown on the right. Note that the "measured distance" pertains to the situation when a line is measured with a tape while the "laying out distance" refers to the situation when a specified or required length is to be laid out with a tape.
CORRECTIONS IN TAPING
Taping is the linear measurement of the horizontal distance between two points using a surveyor's tape. The purpose of taping operations could either be to determine an unknown length or to lay out a required specified length. Corrections to taping are applied by using the summarized rules shown on the right. Note that the "measured distance" pertains to the situation when a line is measured with a tape while the "laying out distance" refers to the situation when a specified or required length is to be laid out with a tape.
1. CORRECTION DUE TO INCORRECT TAPE LENGTH
The correction per tape length is determined from the absolute value of the difference between the true or actual length of the tape and the nominal length of the tape (corr = | measured length - nominal length |). From the sample problem on the left, the correction was determined by subtracting 49.950m from 50m and obtained the correction of 0.050m. Note that the discrepancy is normally assumed to be distributed uniformly throughout the tape and is directly proportional to the fractional segment of the tape used. To determine the total correction to be applied to each dimension of the building, use the formula: corr x (measured length or length to be laid out / nominal length). The correction to be applied for the width of the building is 0.038m and for the length is 0.045m. Knowing that the tape is to be laid out and is too short, thus, the correction should be added. Therefore, the corrected width is 38.038m and the corrected length is 45.045m. Further, to determine the diagonal of the building, I just used the Pythagorean's Theorem (c2 = a2 + b2) since the diagonal cuts the building into two right triangles.
The correction per tape length is determined from the absolute value of the difference between the true or actual length of the tape and the nominal length of the tape (corr = | measured length - nominal length |). From the sample problem on the left, the correction was determined by subtracting 49.950m from 50m and obtained the correction of 0.050m. Note that the discrepancy is normally assumed to be distributed uniformly throughout the tape and is directly proportional to the fractional segment of the tape used. To determine the total correction to be applied to each dimension of the building, use the formula: corr x (measured length or length to be laid out / nominal length). The correction to be applied for the width of the building is 0.038m and for the length is 0.045m. Knowing that the tape is to be laid out and is too short, thus, the correction should be added. Therefore, the corrected width is 38.038m and the corrected length is 45.045m. Further, to determine the diagonal of the building, I just used the Pythagorean's Theorem (c2 = a2 + b2) since the diagonal cuts the building into two right triangles.
2. CORRECTION DUE TO SLOPE
Shown on the right are the different formulas used when reducing slope measurements to equivalent horizontal distances. Note that Ch is the correction for slope, h is the difference in elevation between tape ends and s is the slope measurement. Further, the above sample problem simply asked for the horizontal distance. What I did first is subtract the two given elevations to determine the h which is 34.81m. Then, to get the horizontal distance, I subtracted the correction for slope from the slope measurement and I obtained 544.27m.
3. CORRECTION DUE TO ALIGNMENT
Alignment errors are generally the least serious of the various types of taping errors. It is easier to control, and the magnitude of the resulting error is much smaller. When taping through grass or in a strong wind, it is often difficult to keep the tape perfectly aligned with the end marks. The linear error caused by inaccurate tape alignment is similar to the effect of slope and can be computed in the same way. The only difference is that both h and s are in the horizontal plane; that is, h is the distance the tape is off-line at one end and s is the length of the tape used.
Alignment errors are generally the least serious of the various types of taping errors. It is easier to control, and the magnitude of the resulting error is much smaller. When taping through grass or in a strong wind, it is often difficult to keep the tape perfectly aligned with the end marks. The linear error caused by inaccurate tape alignment is similar to the effect of slope and can be computed in the same way. The only difference is that both h and s are in the horizontal plane; that is, h is the distance the tape is off-line at one end and s is the length of the tape used.
4. CORRECTION DUE TO TEMPERATURE
The tape lengthens as the temperature rises and shortens as the temperature falls. The correction applied to the length of the tape due to change in temperature is given by the formula: Ct = kL (T – Ts) where Ct is the correction for temperature; k is the coefficient of thermal expansion which is equal to 0.0000116/°C; L is the length of the measured line; T is the temperature during actual measurement, and Ts is the temperature during standardization of tape. By substituting the given quantities from the sample problem, the obtained correction for temperature is 0.638m. Note that it is common that the temperature of the field is always greater than the temperature at which the tape is standardized. This results in an increase in tape length, making the measured length shorter since the measuring gaps extended. Henceforth, the correction is additive. For instance, the correct length to be laid out is 2500m + 0.638m or 2500.638m.
The tape lengthens as the temperature rises and shortens as the temperature falls. The correction applied to the length of the tape due to change in temperature is given by the formula: Ct = kL (T – Ts) where Ct is the correction for temperature; k is the coefficient of thermal expansion which is equal to 0.0000116/°C; L is the length of the measured line; T is the temperature during actual measurement, and Ts is the temperature during standardization of tape. By substituting the given quantities from the sample problem, the obtained correction for temperature is 0.638m. Note that it is common that the temperature of the field is always greater than the temperature at which the tape is standardized. This results in an increase in tape length, making the measured length shorter since the measuring gaps extended. Henceforth, the correction is additive. For instance, the correct length to be laid out is 2500m + 0.638m or 2500.638m.
5. CORRECTION DUE TO TENSION
At a standard tension, some tapes are already calibrated to account for sag. Errors occur in this case when the tape is pulled at a tension that differs from the standard tension used during standardization. When a tension less than the standard tension is applied to the tape, it will be pulled less than its standard length, causing the tape to be too long. The tape stretches in an elastic manner, since the modulus of a material can be expressed as the ratio of unit stress to unit elongation, the change in length can be determined as follows: Cp = [(P – Ps)L] / AE where Cp is the correction due to tension, P is the applied pull during measurement, Ps is the applied pull during standardization of tape, A is the cross-sectional area of tape, and E is the modulus of elasticity. In some cases, the cross-sectional area is not given such as the sample problem on the left. Use the formula A = W / (L x Unit Weight) where W and L are the weight and length of the tape respectively, and the unit weight of a steel is approximately 7.866 x 10-3 kg/cm3. The obtained cross-sectional area of the tape is 0.06cm2, the correction is 0.04m, and the correct length is 938.59m.
At a standard tension, some tapes are already calibrated to account for sag. Errors occur in this case when the tape is pulled at a tension that differs from the standard tension used during standardization. When a tension less than the standard tension is applied to the tape, it will be pulled less than its standard length, causing the tape to be too long. The tape stretches in an elastic manner, since the modulus of a material can be expressed as the ratio of unit stress to unit elongation, the change in length can be determined as follows: Cp = [(P – Ps)L] / AE where Cp is the correction due to tension, P is the applied pull during measurement, Ps is the applied pull during standardization of tape, A is the cross-sectional area of tape, and E is the modulus of elasticity. In some cases, the cross-sectional area is not given such as the sample problem on the left. Use the formula A = W / (L x Unit Weight) where W and L are the weight and length of the tape respectively, and the unit weight of a steel is approximately 7.866 x 10-3 kg/cm3. The obtained cross-sectional area of the tape is 0.06cm2, the correction is 0.04m, and the correct length is 938.59m.
6. CORRECTION DUE TO SAG
A tape attains its correct length when it is fully supported and subjected to the pull for which it was standardized. In other words, a tape that is not supported along its length will sag and form a catenary between end supports. In determining this correction, the arc is assumed to be a parabola, and is computed using the formula: Cs = (w2L3) / (24P2) or can be rewritten as Cs = (W2L) / (24P2), where, Cs is the correction due to sag, w is the unit weight of the tape, W is the total weight of the tape between supports, L is the unsupported length of tape, and P is the tension or pull applied on the tape. In the sample problem on the right, the first thing I did is I determined the unit weight (w) by dividing the weight of the tape by its length, and I obtained 0.05kg/m. Then, I computed the correction between supports, using the 5m, 10m, and 15m marks of the tape. For instance, the corrections I obtained between supports are 0.0002m, 0.0016m, and 0.0055m. Whereas, for one tape length, I obtained 0.0073m by adding the correction due to sag between supports.
A tape attains its correct length when it is fully supported and subjected to the pull for which it was standardized. In other words, a tape that is not supported along its length will sag and form a catenary between end supports. In determining this correction, the arc is assumed to be a parabola, and is computed using the formula: Cs = (w2L3) / (24P2) or can be rewritten as Cs = (W2L) / (24P2), where, Cs is the correction due to sag, w is the unit weight of the tape, W is the total weight of the tape between supports, L is the unsupported length of tape, and P is the tension or pull applied on the tape. In the sample problem on the right, the first thing I did is I determined the unit weight (w) by dividing the weight of the tape by its length, and I obtained 0.05kg/m. Then, I computed the correction between supports, using the 5m, 10m, and 15m marks of the tape. For instance, the corrections I obtained between supports are 0.0002m, 0.0016m, and 0.0055m. Whereas, for one tape length, I obtained 0.0073m by adding the correction due to sag between supports.
7. CORRECTION DUE TO WIND
A strong wind blowing perpendicular to the direction of taping will cause the middle and unsupported portion of the tape to be pushed to one side of the measured line. This exposes a measurement error that is similar to the effect of sag but is usually much smaller. It is best not to do any taping work on windy days to eliminate the error.
A strong wind blowing perpendicular to the direction of taping will cause the middle and unsupported portion of the tape to be pushed to one side of the measured line. This exposes a measurement error that is similar to the effect of sag but is usually much smaller. It is best not to do any taping work on windy days to eliminate the error.
SALAZAR_Lec_CA#1.pdfLec_CA#1
CHAPTER 1: INTRODUCTION TO SURVEYING LABORATORY
OVERVIEW
This Chapter provides strong foundation in conducting surveys which include task designation, conventional survey equipment, arm and hand signals, and survey field notes and laboratory report preparation which will help the students to do laboratory activities with ease.
This Chapter provides strong foundation in conducting surveys which include task designation, conventional survey equipment, arm and hand signals, and survey field notes and laboratory report preparation which will help the students to do laboratory activities with ease.
LEARNING OBJECTIVES:
At the end of this module, you should be able to:1. Define the importance of various team members’ roles and cite examples of team behaviors that are helpful in the implementation of the fieldwork exercise.2. Demonstrate the different Surveying Arm and Hand Signals3. Describe the different conventional surveying equipment, their uses and how to maintain them.4. Describe the general format for the Laboratory Report
At the end of this module, you should be able to:1. Define the importance of various team members’ roles and cite examples of team behaviors that are helpful in the implementation of the fieldwork exercise.2. Demonstrate the different Surveying Arm and Hand Signals3. Describe the different conventional surveying equipment, their uses and how to maintain them.4. Describe the general format for the Laboratory Report
FIELD SURVEYING PARTY
1. Chief of Party (COP) - the person who is responsible for the overall direction, supervision, and operational control of the survey party. He is also responsible for its logistical and technical requirements, and problems of a field survey operation. He may also consult the superior prior to the field work. Furthermore, the COP is responsible of the cost estimates and disbursements of expenses as well as in submission of reports. The COP is the one called upon to act as expert witness in court.2. Assistant Chief of Party - the person whose duty is to assist the chief of party in the accomplishment of the task assigned to the survey party. He takes over the duties of the chief of party during the absence of the chief. Moreover, he is also responsible in investigating the site prior to the field activity, in the employment of the equipment, and in the preparation of reports for submission to the COP.3. Instrument Man - the person whose duty is to set up, level, and aerate, surveying instruments such as the transit, optical level, theodolite, plane table, and other equipment.4. Technician - the person who is responsible for use and operation of all electronic instruments required in a field work operation. It is his duty to see to it that these equipment are functioning properly.5. Computer - the person whose duty is to perform all computations of survey data and works out necessary computational checks required in a field work operation. 6. Recorder - the person whose duty is to keep a record of all sketches, drawings, measurements and observations taken or needed for a field work operation.7. Head Tapeman - the person responsible for the accuracy and speed of all linear measurements with tape. He determines and directs the marking of stations to be occupied by the surveying instruments and directs the clearing out of obstructions along the line of sight.8. Rear Tapeman - the person whose duty is to assist the head tapeman during taping operations and in other related work.9. Flagman - the person whose duty is to hold the flagpole or range pole at selected points as directed by the instrument man. He helps the tapeman in making measurements.10. Rodman - the person whose primary duty is to hold the stadia or leveling rod when sights are to be taken on it.11. Pacer - the person whose duty is to check all linear measurements made by the tapeman. He assists the tapeman in seeing to it that mistakes and blunders in linear measurements are either reduced or eliminated.12. Axeman/Lineman - the person whose duty is to clear the line of sight of trees, brush, and other obstructions in wooded country. He is also responsible for the security and safety of the members of the survey party at the survey site.13. Aidman - the person whose duty is to render first aid treatment to members of the survey party who are involved in snake and insect's bites, safety, and well-being.14. Utility Men - the persons whose duties are to render other forms of assistance needed by the survey party or as directed by the chief of party. Where a survey vehicle is used, a utility man is designated as driver.
1. Chief of Party (COP) - the person who is responsible for the overall direction, supervision, and operational control of the survey party. He is also responsible for its logistical and technical requirements, and problems of a field survey operation. He may also consult the superior prior to the field work. Furthermore, the COP is responsible of the cost estimates and disbursements of expenses as well as in submission of reports. The COP is the one called upon to act as expert witness in court.2. Assistant Chief of Party - the person whose duty is to assist the chief of party in the accomplishment of the task assigned to the survey party. He takes over the duties of the chief of party during the absence of the chief. Moreover, he is also responsible in investigating the site prior to the field activity, in the employment of the equipment, and in the preparation of reports for submission to the COP.3. Instrument Man - the person whose duty is to set up, level, and aerate, surveying instruments such as the transit, optical level, theodolite, plane table, and other equipment.4. Technician - the person who is responsible for use and operation of all electronic instruments required in a field work operation. It is his duty to see to it that these equipment are functioning properly.5. Computer - the person whose duty is to perform all computations of survey data and works out necessary computational checks required in a field work operation. 6. Recorder - the person whose duty is to keep a record of all sketches, drawings, measurements and observations taken or needed for a field work operation.7. Head Tapeman - the person responsible for the accuracy and speed of all linear measurements with tape. He determines and directs the marking of stations to be occupied by the surveying instruments and directs the clearing out of obstructions along the line of sight.8. Rear Tapeman - the person whose duty is to assist the head tapeman during taping operations and in other related work.9. Flagman - the person whose duty is to hold the flagpole or range pole at selected points as directed by the instrument man. He helps the tapeman in making measurements.10. Rodman - the person whose primary duty is to hold the stadia or leveling rod when sights are to be taken on it.11. Pacer - the person whose duty is to check all linear measurements made by the tapeman. He assists the tapeman in seeing to it that mistakes and blunders in linear measurements are either reduced or eliminated.12. Axeman/Lineman - the person whose duty is to clear the line of sight of trees, brush, and other obstructions in wooded country. He is also responsible for the security and safety of the members of the survey party at the survey site.13. Aidman - the person whose duty is to render first aid treatment to members of the survey party who are involved in snake and insect's bites, safety, and well-being.14. Utility Men - the persons whose duties are to render other forms of assistance needed by the survey party or as directed by the chief of party. Where a survey vehicle is used, a utility man is designated as driver.
Lab_CW#1: Examples of Team Behaviors Helpful in Doing Field Work Exercises
SALAZAR_Lab_CW#1.pdfSURVEYING ARM AND HAND SIGNALS: Useful for Better Communication during Field Work Operations
CENG101L_COURSEWORK 1.1_Catura, Cedano, Clavillas, Credo, de Chavez, Demesa, Dionarce, Doblon_BSCE2A.mp4CONVENTIONAL SURVEYING INSTRUMENTS
1. Measuring Tape - used in surveying for measuring horizontal, vertical or slope distances. Tapes are issued in various lengths and widths, and graduated in variety of ways.2. Range Pole - also known as flags or lining rods, are used as temporary signals to indicate the location of points or the direction of lines, and to mark alignments.3. Chaining pins - sometimes called surveyor’s arrows or taping pins. They are stuck in the ground to mark ends of measured tape lengths or partial tape lengths.4. Wooden Stake or Hub - made of 5cm x 5cm x 30cm wood to mark points, corners, or stations on the ground.5. Plumb bob - used for projecting the tape ends to the ground when the tape must be suspended above the measured line.6. Crayons or chalk - used for marking points, corners or stations by indicating cross marks on paved roads, sidewalks or walls.7. Level - is basically a telescope attached to an accurate leveling device, set upon a tripod so that it can rotate horizontally through 360°.8. Tripod - consists of three legs and a head where the level instrument is mounted. The tripod could be of aluminum or wood material.9. Leveling rod - is a box section of aluminum or wood, which will extend to 3 or 5m in height by telescoping, hinging or addition of sections. One face has a graduated scale attached for reading with the cross-hairs of the level telescope.10. Compass - is a hand-held instrument for determining the horizontal direction of a line with reference to the magnetic meridian.11. Transit - an instrument of precision is used principally to measure and lay off horizontal and vertical angles and in prolonging straight lines.12. Electronic Distance Measurement (EDM) Devices - measure lengths by indirectly determining the number of full and partial waves of transmitted, electromagnetic energy required in traveling between two ends of a line.
1. Measuring Tape - used in surveying for measuring horizontal, vertical or slope distances. Tapes are issued in various lengths and widths, and graduated in variety of ways.2. Range Pole - also known as flags or lining rods, are used as temporary signals to indicate the location of points or the direction of lines, and to mark alignments.3. Chaining pins - sometimes called surveyor’s arrows or taping pins. They are stuck in the ground to mark ends of measured tape lengths or partial tape lengths.4. Wooden Stake or Hub - made of 5cm x 5cm x 30cm wood to mark points, corners, or stations on the ground.5. Plumb bob - used for projecting the tape ends to the ground when the tape must be suspended above the measured line.6. Crayons or chalk - used for marking points, corners or stations by indicating cross marks on paved roads, sidewalks or walls.7. Level - is basically a telescope attached to an accurate leveling device, set upon a tripod so that it can rotate horizontally through 360°.8. Tripod - consists of three legs and a head where the level instrument is mounted. The tripod could be of aluminum or wood material.9. Leveling rod - is a box section of aluminum or wood, which will extend to 3 or 5m in height by telescoping, hinging or addition of sections. One face has a graduated scale attached for reading with the cross-hairs of the level telescope.10. Compass - is a hand-held instrument for determining the horizontal direction of a line with reference to the magnetic meridian.11. Transit - an instrument of precision is used principally to measure and lay off horizontal and vertical angles and in prolonging straight lines.12. Electronic Distance Measurement (EDM) Devices - measure lengths by indirectly determining the number of full and partial waves of transmitted, electromagnetic energy required in traveling between two ends of a line.
EQUIPMENT CARE AND PROTECTION
1. Care shall be taken when moving instrument. Manufacturer's recommendation shall be followed.2. Instruments such as total stations and theodolite should never be lifted by the standard/horizontal axis, rather by their base/ handle.3. When equipment is being moved to or from its case/tripod, it should be lifted by the base handle.4. Never point an instrument's telescope directly at the sun. 5. Never carry an instrument on its tripod over your shoulder except indicated by the owner/manual.6. When equipment is being set-up, the leveling screws should never be tightened any more than necessary.7. Instruments shall be protected from rapid change of temperature.8. Care needs to be taken to not over stress equipment.9. Electronic of should not be subjected to extended periods of time in wet weather.10. Equipment left set up during rainshowers will be covered by a waterproof covering. Equipment that becomes wet shall be allowed to dry prior to storing.11. Equipment should never be left unattended in areas where it might be knocked over or disturbed.12. Whenever possible, select instrument set up locations to minimize the exposure to the operator, other members of the crew, and the instrument to danger.13. All instruments shall be stored in a safe, secure area when not in use.
1. Care shall be taken when moving instrument. Manufacturer's recommendation shall be followed.2. Instruments such as total stations and theodolite should never be lifted by the standard/horizontal axis, rather by their base/ handle.3. When equipment is being moved to or from its case/tripod, it should be lifted by the base handle.4. Never point an instrument's telescope directly at the sun. 5. Never carry an instrument on its tripod over your shoulder except indicated by the owner/manual.6. When equipment is being set-up, the leveling screws should never be tightened any more than necessary.7. Instruments shall be protected from rapid change of temperature.8. Care needs to be taken to not over stress equipment.9. Electronic of should not be subjected to extended periods of time in wet weather.10. Equipment left set up during rainshowers will be covered by a waterproof covering. Equipment that becomes wet shall be allowed to dry prior to storing.11. Equipment should never be left unattended in areas where it might be knocked over or disturbed.12. Whenever possible, select instrument set up locations to minimize the exposure to the operator, other members of the crew, and the instrument to danger.13. All instruments shall be stored in a safe, secure area when not in use.
LABORATORY REPORT FORMAT
1. Title Page (sample on the right)2. Introduction3. Method & Equipment Used4. Procedure - Field Party Survey Assignments -Special Methods -Problems Encountered5. Data and Calculations6. Results -Raw Results -Adjustments7. Conclusions -Learnings -Rooms for Improvements8. References
1. Title Page (sample on the right)2. Introduction3. Method & Equipment Used4. Procedure - Field Party Survey Assignments -Special Methods -Problems Encountered5. Data and Calculations6. Results -Raw Results -Adjustments7. Conclusions -Learnings -Rooms for Improvements8. References
CENG101_MidtermExam_Oct15_2022.pdfMIDTERM EXAM
REFLECTION
LEC: At first, I thought the subject was very hard and challenging. This was the first subject when we had our first face to face classes last August and unfortunately, I arrived late that time and Ma'am May had already discussed some topics. Though it was more like orientation, my mind that time was like floating in the air that somehow everything that Ma'am May was discussing was not sinking in my head. That is why, I thought that the subject would be very hard. Nonetheless, I just copied some of the notes of my classmates and reviewed them at home. The module 1 really taught me the basics of surveying. I can even tell the definition of surveying in my own words. For instance, surveying is the measurement of horizontal and vertical distances, directions, and angles of relative positions on the earth's surface. I also realized that there are many types of surveying which are basically depending on the location the survey is conducted or depending on the purpose of the survey. To easily familiarize the types of surveys, I made a mnemonic 3C-F-HIM-PRT which means cadastral, city, construction, forestry, hydrographic, industrial, mine, photogrammetric, route, and topographic surveys. Furthermore, one of the highlight topics I learned in this module is the most probable value which is simply the arithmetic mean or the average of the observations. I also realized that perfection is hard to achieve in taping. What I mean is, there will always be a correction. After all, correction comes from various sources such as correction due to incorrect tape length, correction due to slope, correction due to alignment, correction due to temperature, correction due to tension, correction due to sag, and correction due to wind. I am already familiar with the formulas on getting these kinds of correction especially knowing that surveying is included in the civil engineering board exam. Note that the formulas of correction due to alignment and due to wind are almost the same with how correction due to sag is obtained. Overall, it was not that hard. But it was not easy too. I would say that somehow, I am a bit satisfied with how I processed and understood the lessons.
LAB: The introduction of the surveying laboratory was actually Ma'am May's topic during the first face to face class. She discussed the needed contents on the field notes, the members of the field survey party, the lab report order, and the equipment care and protection. She also gave the instructions for the field work #1. Though, I was not so attentive that time, I felt a bit nervous for the subject for I know that skills are needed in doing the field works and I didn't think I have enough skills needed for the field works. But I guess my nervousness was mostly on the instructions Ma'am May gave for the field work #1 that I totally did not understand. Basically, I was scared that when the day of the field work came, I do not know what to do. Nevertheless, the result of the field work #1 is part of the course learning outcome 2. Going back to what Ma'am May discussed, I learned that a field survey party should be composed of 14 team members but since not all positions are required in every field work, our groups were mostly 6 to 7 members. The important positions to fill in are the chief of party, assistant chief of party, head tapeman, rear tapeman, computer, recorder, pacer, aidman, rodman, and instrument man. Since there were only 6 to 7 members in each group, we just had double roles for a single person such as the recorder could also be the computer, or maybe the pacer could also be the aidman. Furthermore, I also learned that the equipment should be taken care of at all times since the accuracy of the measurements will be affected by the condition of the instruments. Also, if for example, we damaged one instrument, we need to pay for it as what Ma'am May said. I remember that I bought one umbrella after Ma'am May told us that the instruments should not get wet especially during rainshowers. In other words, we need to cover them as much as we could.
LEC: At first, I thought the subject was very hard and challenging. This was the first subject when we had our first face to face classes last August and unfortunately, I arrived late that time and Ma'am May had already discussed some topics. Though it was more like orientation, my mind that time was like floating in the air that somehow everything that Ma'am May was discussing was not sinking in my head. That is why, I thought that the subject would be very hard. Nonetheless, I just copied some of the notes of my classmates and reviewed them at home. The module 1 really taught me the basics of surveying. I can even tell the definition of surveying in my own words. For instance, surveying is the measurement of horizontal and vertical distances, directions, and angles of relative positions on the earth's surface. I also realized that there are many types of surveying which are basically depending on the location the survey is conducted or depending on the purpose of the survey. To easily familiarize the types of surveys, I made a mnemonic 3C-F-HIM-PRT which means cadastral, city, construction, forestry, hydrographic, industrial, mine, photogrammetric, route, and topographic surveys. Furthermore, one of the highlight topics I learned in this module is the most probable value which is simply the arithmetic mean or the average of the observations. I also realized that perfection is hard to achieve in taping. What I mean is, there will always be a correction. After all, correction comes from various sources such as correction due to incorrect tape length, correction due to slope, correction due to alignment, correction due to temperature, correction due to tension, correction due to sag, and correction due to wind. I am already familiar with the formulas on getting these kinds of correction especially knowing that surveying is included in the civil engineering board exam. Note that the formulas of correction due to alignment and due to wind are almost the same with how correction due to sag is obtained. Overall, it was not that hard. But it was not easy too. I would say that somehow, I am a bit satisfied with how I processed and understood the lessons.
LAB: The introduction of the surveying laboratory was actually Ma'am May's topic during the first face to face class. She discussed the needed contents on the field notes, the members of the field survey party, the lab report order, and the equipment care and protection. She also gave the instructions for the field work #1. Though, I was not so attentive that time, I felt a bit nervous for the subject for I know that skills are needed in doing the field works and I didn't think I have enough skills needed for the field works. But I guess my nervousness was mostly on the instructions Ma'am May gave for the field work #1 that I totally did not understand. Basically, I was scared that when the day of the field work came, I do not know what to do. Nevertheless, the result of the field work #1 is part of the course learning outcome 2. Going back to what Ma'am May discussed, I learned that a field survey party should be composed of 14 team members but since not all positions are required in every field work, our groups were mostly 6 to 7 members. The important positions to fill in are the chief of party, assistant chief of party, head tapeman, rear tapeman, computer, recorder, pacer, aidman, rodman, and instrument man. Since there were only 6 to 7 members in each group, we just had double roles for a single person such as the recorder could also be the computer, or maybe the pacer could also be the aidman. Furthermore, I also learned that the equipment should be taken care of at all times since the accuracy of the measurements will be affected by the condition of the instruments. Also, if for example, we damaged one instrument, we need to pay for it as what Ma'am May said. I remember that I bought one umbrella after Ma'am May told us that the instruments should not get wet especially during rainshowers. In other words, we need to cover them as much as we could.
REFERENCES:
https://static.vecteezy.com/system/resources/previews/007/766/035/large_2x/gps-surveying-equipment-on-blue-sky-and-white-clouds-background-gps-gis-and-gnss-equipment-land-survey-for-map-technology-for-marks-land-to-made-satellite-map-on-the-earth-smart-gnss-gps-survey-free-photo.jpghttps://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQHQ-uX9WH12BEGwxQxzNEkx-3fn4FzpiJEeQ&usqp=CAUhttps://static.vecteezy.com/system/resources/previews/003/355/482/original/collection-set-of-check-mark-exclamation-point-free-vector.jpghttps://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/image/quality_sys_random.gifhttps://civilengineering-softstudies.com/51-what-are-mistakessystematic-error-and-accidental-errors-in-surveying.htmlhttps://www.civilprojectsonline.com/wp-content/uploads/2010/12/Errors.jpghttps://techqualitypedia.com/accuracy-and-precision/https://sciencenotes.org/wp-content/uploads/2021/08/Accuracy-and-Precision.pnghttps://slideplayer.com/slide/10730158/37/images/5/Probability+curve.jpghttps://www.theprojectdefinition.com/relative-precision/https://www.studocu.com/ph/document/technological-institute-of-the-philippines/elementary-surveying/13-weights-of-observation-ce-103-surveying-1-converted/18507272https://www.slideshare.net/BroddettAbatayo/ge-105-lecture-2-taping-correction-by-broddett-b-abatayohttps://web.itu.edu.tr/~coskun/contents/lessons/topo/week_2.pdfhttps://www.wikiwand.com/en/Tape_correction_(surveying)https://static.vecteezy.com/system/resources/thumbnails/009/763/309/small/the-icon-of-the-wind-that-bends-the-green-tree-concept-of-weather-tornado-and-other-elements-of-nature-flat-illustration-isolated-on-white-background-vector.jpghttps://studylib.net/doc/25472169/1.-elementary-surveying---introduction-to-surveying
https://images4.alphacoders.com/652/thumb-1920-652737.jpghttps://www.survey-solutions.co.uk/wp-content/uploads/2020/07/Project-17-Bishops-Lydeyard.jpghttps://t4.ftcdn.net/jpg/02/98/68/73/360_F_298687332_D0GAA6fAgr70NWtF8UKXPyLx0mTGug0x.jpghttps://i.pinimg.com/originals/ff/cf/d1/ffcfd1e82699b5b51e2f20438a9d8ccc.jpghttps://i.pinimg.com/originals/32/96/9c/32969c8d097e908ffa28514c98253454.jpghttps://wallpaperaccess.com/full/4149226.jpghttps://i.pinimg.com/originals/5c/ad/e6/5cade6da6c5e0eed3bc7f59e03c36c42.jpghttps://cutewallpaper.org/cdn-cgi/mirage/dd19f2d06ebc24f541f142b37b4289ffa7de722a7607e39984c5c6dd4ce8defd/1280/27x/1vzl6pojd/142661618.jpg
https://images4.alphacoders.com/652/thumb-1920-652737.jpghttps://www.survey-solutions.co.uk/wp-content/uploads/2020/07/Project-17-Bishops-Lydeyard.jpghttps://t4.ftcdn.net/jpg/02/98/68/73/360_F_298687332_D0GAA6fAgr70NWtF8UKXPyLx0mTGug0x.jpghttps://i.pinimg.com/originals/ff/cf/d1/ffcfd1e82699b5b51e2f20438a9d8ccc.jpghttps://i.pinimg.com/originals/32/96/9c/32969c8d097e908ffa28514c98253454.jpghttps://wallpaperaccess.com/full/4149226.jpghttps://i.pinimg.com/originals/5c/ad/e6/5cade6da6c5e0eed3bc7f59e03c36c42.jpghttps://cutewallpaper.org/cdn-cgi/mirage/dd19f2d06ebc24f541f142b37b4289ffa7de722a7607e39984c5c6dd4ce8defd/1280/27x/1vzl6pojd/142661618.jpg
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