GE REVIEW SET Flashcards
(282 cards)
1
Q
Based on CMO No. 89, series of 2017, a branch
of engineering which deals with the collection and measurement of spatial data above, on, or
below the surface of the earth using appropriate technologies and the scientific and
methodological processing and management of these data for the production of spatial
information systems, maps, plans, charts, and other documents.
A
Geodetic Engineering
2
Q
it deals with the collection and measurement of spatial data or information which is also known as
A
geospatial data or geographic information
3
Q
It is the data or information that identifies the ___________ It is the data or information that identifies the
A
geographic location features and boundaries
4
Q
means the location of the information is known in three dimensional (3D) space. It is often accessed, manipulated, or analyzed through GIS
A
“spatial”
5
Q
According to the Dept. of Surveying and Spatial Information Science, Univ. of Tasmania, is the science concerned with the measurement,
representation, analysis, management, retrieval, and display of spatial information
describing both the Earth’s physical features and built-in environment.
A
Geomatics Engineering
6
Q
In applied science, it involves an
A
integrated approach to the measurement, analysis, management, and display of geographic and other spatial data
7
Q
have specialist skills, knowledge, and understanding to provide services that meet the needs of society and which contribute to social and political stability, quality of life, and the management of natural heritage and resources.
A
Geomaticians
8
Q
Discipline of Geomatics
A
Surveying, Geodesy, Remote Sensing and Photogrammetry, Global Positioning System, Geographic Information System, Cartography
9
Q
The oldest historical records in existence today that bear directly on the subject of surveying state that this science began in
A
Egypt
10
Q
recorded that Sesostris (about 1400 B.C.) divided the land of Egypt into plots for taxation
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Herodotus
11
Q
swept away portions of these plots and surveyors were appointed to replace the boundaries.
A
Annual floods of the Nile River
12
Q
These early surveyors were called _________ since their measurements were made with ropes having markers at unit distance
A
rope-stretchers
13
Q
These early surveyors were called _________ since their measurements were made with ropes having markers at unit distance
A
rope-stretchers
14
Q
the Great-Great Grandfather of
Engineering, is one of the most intelligent innovators ever.
A
Heron of Alexandria
15
Q
He stands out prominently for applying science to surveying in about 120 B.C. He was the author of several important treatises of interest to surveyors, the Dioptra, which related the methods of surveying a field, drawing a plan, and making related calculations.
A
Heron of Alexandria
16
Q
It is also described as one of the first pieces of equipment recorded.
A
Dioptra
17
Q
a is a classical astronomical and surveying instrument. It was a sighting tube or a rod with a sight at both ends, attached to a standand if fitted with protractors, it could be used to measure angles.
A
Dioptra
18
Q
was the most authoritative among Greek and Egyptian surveyors
A
Heron’s work
19
Q
was among the first to compute the Earth’s dimension. His procedure occurred at around 200 B.C.
A
Eratosthenes
20
Q
He had observed that on the day of the summer
solstice, the midday sun shone to the bottom of a well in the town of Syene (Aswan)
A
Eratosthenes
21
Q
he observed the sun was not directly overhead at
Alexandria; instead, it cast a shadow with the vertical equal to 1/50th of a circle (7° 12’)
A
Eratosthenes
22
Q
Eratosthenes applied certain “known” facts that
A
(1) on the day of the summer solstice, the midday sun was directly over the line of the summer Tropic Zone (Tropic of Cancer)-Syene was therefore concluded to be on this line; (2) the linear distance between Alexandria and Syene was 500 miles; (3) Alexandria and Syene lay on a direct north-south
line.
23
Q
concluded that since the angular deviation of the sun from the vertical at Alexandria was also the angle of the subtended arc, the linear distance between Alexandria and Syene was 1/50 of the
circumference of the earth or 50 x 500 = 25,000 miles.
A
Eratosthenes
24
Q
have the same basic characteristics that of delineating a portion of the Earth’s surface of establishing the boundaries of some object upon it.
A
All surveying operations
25
is a branch of applied mathematics that is concerned with determining the area of any portion of the earth’s surface, the lengths and directions of the bounding lines, and the contour of the surface and with accurately delineating the whole paper
Surveying
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is the science, art, and technology of determining the relative positions of points above, on, or beneath the Earth’s surface, or of establishing such points - Ghilani and Wolf.
Surveying
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is the art and science of determining angular and linear measurements to establish the form, extent, and relative position of points, lines, and areas on or near the surface of the earth or on other extraterrestrial bodies through applied mathematics and the use of specialized equipment and techniques.
Surveying
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expanded in engineering construction, planning, and design.
use of surveying
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expanded in engineering construction, planning, and design.
use of surveying
30
also cover a wide range in scope and complexity such as staking out of simple structures, surveying of small parcels of land and extensive and difficult surveys required in the construction of subdivisions, bridges, highways, canals, dams, railroads, wharves, missile and rocket launching sites, drainage and irrigation systems and surveys of relatively large portions of the earth’s surface.
Surveys
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Classification of Surveys
Plane Surveying and Geodetic Surveying
32
It is a type of surveying in which the earth is considered to be a flat surface, and where distances and areas involved are of the limited extent that the exact shape of the earth is disregarded.
Plane Surveying
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They are surveys of a wide extent which take into account the spheroidal shape of the earth.
Geodetic Surveying
34
Types of Surveys
Cadastral surveys, City surveys, Construction surveys, Forestry surveys, Hydrographic surveys, Industrial surveys, Mine surveys, Photogrammetric surveys, Route surveys, Topographic surveys
35
are usually closed surveys that are undertaken in urban and rural locations to determine and define property lines and boundaries, corners, and areas.
Cadastral surveys
36
are conducted of the areas in and near a city to plan expansions or improvements, locate property lines, fixing reference monuments, determining the physical features and configuration of the land, and preparing maps.
City surveys
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are undertaken at a construction site to provide data regarding grades, reference lines, dimensions, ground configuration, and the location and elevation of structures which are of concern to engineers, architects, and builders.
Construction surveys
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are executed in connection with forest management and mensuration, and the production and conservation of forest land.
Forestry surveys
39
refer to surveying streams, lakes, reservoirs, harbors, oceans, and other bodies of water
Hydrographic surveys
40
are sometimes known as optical tooling and it refers to the use of surveying techniques in shipbuilding, construction, and assembly of aircraft, layout, and installation of heavy and complex machinery, and other industries where very accurate dimensional layouts are required.
Industrial surveys
41
are performed to determine the position of all underground excavations and surface mine structures, to fix surface boundaries of mining claims, determine geological formations, to calculate excavated volumes, and establish lines and grades for other related mining work.
Mine surveys
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are the type of survey which makes use of photographs taken with specially designed cameras either from airplanes or ground stations.
Photogrammetric surveys
43
involve the determination of alignment, grade, earthwork quantities, location of natural and artificial objects in connection with the planning, design, and construction of highways, railroads, pipelines, canals, transmission lines, and other
linear projects
Route surveys
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are made for determining the shape of the ground, and the location and elevation of natural and artificial features
Topographic surveys
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For an organization for a field survey party, the _________ must be
adapted.
principle of flexibility
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The person who is responsible for the overall direction, supervision, and operational control of the survey party and its logistics and technical requirements and problems of field survey operations.
Chief of Party
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The person whose duty is to assist the chief of party. He takes over the duties of the chief of party during the absence of the chief. He conducts
ground reconnaissance and investigates sites of a proposed project to gather necessary
data before the start of survey work.
Assistant Chief of Party
48
The person whose duty is to set up, level, and operate surveying instruments. He sees to it that the instruments to be used in a survey operation are in good working condition and proper adjustment.
Instrument man
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. The person who is responsible for the use and operation of all electronic instruments required in a fieldwork operation. He is also responsible for the establishment of a two-way communication link by radio between members of the survey party where distant stations or long survey lines are involved.
Technician
50
The person whose duty is to perform all computations of survey data and works out necessary computational checks required in a fieldwork operation. He is responsible for the utilization of electronic calculators, pocket or microcomputers, and assists in the operation of computerized surveying systems and equipment.
Computer
51
The person whose duty is to keep a record of all sketches, drawings, measurements, and observations taken or needed for a fieldwork operation. He keeps a table of schedules of all phases of work and the employment of the members of the survey party
Recorder
52
The person was 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.
Head Tapeman
53
The person whose duty is to assist the head tapeman during taping operations and in other related work.
Rear Tapeman
54
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 and assists the axeman in cutting down branches and in clearing other
obstructions to line of sight
Flagman
55
The person whose primary duty is to hold the stadia or leveling rod when sights are to be taken on it.
Rodman
56
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. He may also perform the job of a rodman.
Pacer
57
The person must clear the line of sight. He is also responsible for the security and safety of the members of the survey party at the survey site
Axeman/Lineman
58
The person whose duty is to render first aid treatment to members of the survey party who are involved in snake and insect bites, accidents, and other cases involving their health, safety, and well-being
Aidman
59
The persons whose duty is to render other forms of assistance needed by the survey party or as directed by the chief of the party. He is also designated as the driver and is responsible for setting the campsite and its required facilities if the survey party has to camp out for days in the field.
Utilityman
60
constitute the only reliable and permanent record of actual work done in the field. No matter how carefully the measurements are made, the survey as a whole may be useless if some of the measurements are not recorded or if the meaning of other recorded data is misinterpreted or misunderstood
Surveying field notes
61
become the official record of the survey
field notes
62
is always aided by methodical apportionment and classification of data
Accuracy
63
is always aided by methodical apportionment and classification of data
Accuracy
64
is made of good quality rag paper with stiff board or leather cover made to withstand hard usage and of pocket-size
Engineer’s field book
65
THE SURVEY PARTY
Chief of Party, Assistant Chief of Party, Instrument man, Technician, Computer, Recorder, Head Tapeman, Rear Tapeman, Flagman, Rodman, Pacer, Axeman/Lineman, Aidman, Utilityman
66
TYPES OF NOTES
Sketches, Tabulations, Explanatory Notes, Computations, Combination of the Above,
67
will help to convey a correct impression. It is rarely made to exact scale but in most cases, it is made approximately to scale.
Sketches
68
A series of numerical values observed in the field are best shown in a tabulated format. Tabulated form of note keeping conveys the required information in a simple and definite manner
Tabulations
69
It provides a written description of what has been done in the field. These are employed to make clear what the numerical data and sketches fail to
do
Explanatory Notes
70
Calculations form a large part of the work of surveying. Most surveying type computations are made algebraically by the use of simple arithmetical steps and trigonometric functions.
Computations
71
The practice used in most extensive surveys is a
combination of the above types of notes depending on which type of combination
would be most logical to use in portraying the type of data gathered in the field.
Combination of the Above
72
RECORDING OBSERVED DATA
1. Follow a consistent simple style of lettering.
2. Use a sharp pencil.
3. Make it a habit to record directly in the field book immediately following a
measurement, rather than on a sheet of scratch paper for copying later.
4. Do not erase recorded data.
5. Avoid crowding observed data in the field notebook.
6. Always bring along a straightedge for ruling lines and a small protractor for laying off
angles in the field notebook.
7. To avoid the possible misinterpretation of data, use sketches instead of tabulations.
Also, use explanatory notes.
8. Indicate north at the top of the page of the field notebook for all sketches shown in the
plan and draw a meridian arrow.
9. Tabulated values should be kept inside the column rulings, with the decimal point and
digits aligned vertically.
10. Computations made in the field should be recorded in the field notebook so that they
can be checked later.
11. Number every page of the field notebook
73
are any gesture or motion that conveys information or gives a command, direction, or warning. It is usually difficult or impossible to communicate verbally in the field due to distance, wind conditions, and surrounding noise. It is necessary or practical to use signals rather than call directions since much of the work involves long
sights where calling to one another is impractical.
arm and hand signals
74
commonly used arm and hand signals
1. Move Right or Left
2. Give a Sight
3. All Right
4. This is a Point
5. Move Back
6. Pick Up Instruments
7. Raise or (Lower) Target
8. Come In
9. Plumb the Rod
10. Establish a Turning Point
11. This is a Turning Point
12. Wave the Rod
13. Face the Rod
14. Reverse the Rod
15. Move Forward
16. Use the Long Rod
75
PROPER HANDLING OF INSTRUMENTS
▪ Know how to use the instruments.
▪ Always place them in stable grounds when in use.
▪ Place them properly in their storage/container.
▪ Do not use them if the weather does not permit.
▪ Check their functionality before and after fieldwork.
▪ If wet, dry them by carefully wiping excess water and do not put them immediately
in their storage/container.
▪ Carry the instrument properly.
▪ Be mindful of the surrounding when transporting any equipment.
▪ Avoid playing with the instrument.
▪ Always make sure that the equipment is secure.
76
is the process of determining the extent, size, or dimensions of a particular quantity in comparison to a given standard.
Measurement
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It consists of several physical operations that render numerical values. It was concentrated on angles, elevations, times, lines, areas, and volumes.
Measurement
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are never exact and they will always imperfect no
matter how carefully made
Measurement
79
In surveying, the measurement may be made
directly and indirectly
80
is a comparison of measured quantity with a standard measuring unit or units employed for measuring a quantity of that kind such as applying wire or tape to a line, determining a horizontal or vertical angle with transit, or fitting a protractor between two intersecting lines to determine the intersecting angles
Direct measurement
81
the observed value is determined by the relationship to some other known values such as the total length of a line would be an indirectly observed distance if it is determined by a summation of a series of directly measured short segments
indirect measurement
82
is a single, unadjusted determination of a linear or angular value. A single reading of an angle or a single reading of an EDM is an observation
observation
83
is a quantity that is obtained by instrumental measurement of the quantity
observed value
84
is an observation of the desired quantity while an indirect observation is a quantity computed from direct observations.
Direct observation
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is the entire process of obtaining the desired quantity. It entails performing a physical operation that usually consists of several more elementary operations such as preparations (instrument calibration and setup), pointing, matching, and comparing
Measurement
86
The result of these physical operations renders a numerical value that is called a
“measurement”
87
In surveying, measurement entails both
linear and angular measurements
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is used in the Philippines effective January 01, 1983, phasing out the English System
SI (International System)
89
When using SI, all measurements are based upon the
“meter”
90
are derived from it in decimal steps and their names are formed by adding prefixes
Larger and smaller units
91
The common units for length are the
kilometer, meter, centimeter, and millimeter
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may also refer to other linear dimensions such as width, depth, thickness, height, or distance
Length
93
is used for long distances
kilometer
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measurement of objects such as buildings, structures, residential lots, heights of mountains, tides, pipes, and cables
meter
95
are not commonly used in surveying because they were suitable only for small dimensions
centimeter and millimeter
96
The unit of area in SI
square meter
97
used for very small areas
Square centimeters and millimeters
98
is commonly used for the measurement of large tracts of land
hectare (ha)
99
common metric units for volume
cubic meter, liter, and the millimeter
100
is used for larger volumes which are common in engineering constructions and in measuring various quantities in surveying
cubic meter
101
The SI units for plane angles
radian
102
is the supplementary unit of a solid angle
steradian
103
sexagesimal units of angular measurements
degree, minute, and second
104
unit of the angle used in surveying
degree
105
used grad as their angular units
centesimal units
106
is divided into 100 centesimal minutes or 0.9 degrees
grad
107
is divided into 100 centesimal seconds or 0 degrees 00 minutes 32.4 seconds
minute
108
are usually expressed in decimals.
Grads
109
includes the number of certain digits
plus one digit that is estimated, and therefore, questionable or uncertain
number of significant figures
110
is often confused with the number of decimal places
number of significant figures
111
may have to be used to maintain the correct number of significant figures but in themselves, they do not indicate significant figures
Decimal places
112
is the process of dropping one or more of the final digits so that the value contains only the significant figure required
Rounding off numbers
113
is defined as the difference between the true value and the measured value of a quantity. It is a deviation an observation or a calculation from the true value and it's beyond the control of the one operating.
error
114
are inaccuracies in measurements which occur because some aspect of a surveying operation is performed by the surveyor with carelessness, inattention, poor judgment, and improper execution
Mistakes
115
A large mistake is referred to as
blunder
116
are not classified errors because they are usually so gross in magnitude compared to
the other types of errors
Mistakes and blunders
117
Common mistakes or blunders
reading the wrong graduation on the tape,
omitting a whole length of tape,
transposition of figures,
reading a scale backward,
misplacing a decimal
point,
incorrect recording of field notes,
and sighting the wrong target
118
In surveying, _________ in measurements are either systematic or accidental
errors
119
This type of error is one that will always have the same sign and magnitude as long as field conditions remain constant and unchanged. It will
repeat itself in another measurement, still maintaining the same sign, and thus will
accumulate
Systematic/ Cumulative Error
120
Types of Systematic Errors
Constant Error and Counteracting
121
If its magnitude and sign remain the same throughout the measuring process/field conditions are unchanged.
Constant Error
122
If its sign changes while its magnitude remains the same perhaps due to the personal bias of the observer
Counteracting
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If its sign changes while its magnitude remains the same perhaps due to the personal bias of the observer
Counteracting
124
These errors are purely accidental. The occurrence of such errors are matters of chance as they are likely to be positive or negative, and may tend in part to compensate or average out according to laws of probability.
Accidental Errors
125
Sources of Errors
Instrumental Errors, Natural Errors, and Personal Errors
126
These errors are due imperfections in the instrument used, either from faults in their construction or from improper adjustments between the different parts before their use.
Instrumental Errors
127
Instrumental Errors
* Measuring with a steel tape of incorrect length.
* Using a leveling rod with painted graduations not perfectly spaced.
* Determining the difference in elevation between two points with an instrument
whose line of sight is not in adjustment.
* Sighting on a warped rod.
* Improper adjustment of the plate bubbles of transit or level.
128
These errors are caused by variations in the phenomena of nature such as changes in magnetic declination, temperature, humidity, wind, refraction, gravity, and curvature of the earth.
Natural Errors
129
Natural Errors
* The effect of temperature variation on the length of a steel tape.
* Error in the readings in the magnetic needle due to the variations in magnetic
declination.
* Deflection of the line of sight due to the effect of the earth ‘s curvature and
atmospheric refraction.
* Error in the measurement of a line with a tape being blown sidewise by a strong
wind.
* Error in the measurement of a horizontal distance due to slope or uneven
ground.
130
These errors arise principally from the limitations of the senses of sight, touch, and hearing of the observer which are likely to be erroneous or
inaccurate. Some personal errors are constant, some are compensating, while others may be erratic
Personal Errors
131
Personal Errors
* Error in determining a reading on a rod that is out of plumb during the
sighting.
* Error in the measurement of a vertical angle when the crosshairs of the
telescope are not positioned correctly on the target.
* Making an erroneous estimate of the required pull to be applied on a steel
tape during measurement.
132
aids in decision making provides comparison, explains action that has taken place, justifies a claim or assertion, predicts future outcome, and estimates unknown quantities. It also summarizes data for public use
statistics
133
aids in decision making provides comparison, explains action that has taken place, justifies a claim or assertion, predicts future outcome, and estimates unknown quantities. It also summarizes data for public use
statistics
134
is a summary statistic that represents the center point or typical value of a dataset. These measures indicate where most values in a distribution fall
and are also referred to as the central location of a distribution
measure of central tendency
135
In statistics, the three most common measures of central tendency
mean, median, and mode.
136
is the sum of all the values of the
observations divided by the number of observations and it is probably the most
familiar measure of central tendency used. It was affected by the value of every observation.
In particular, it is strongly influenced by extreme values.
mean or Most Probable Value (MPV)
137
mean or Most Probable Value (MPV)
MPV=X=X/n=(X1+X 2 + X3+....+Xn)/ n
138
is the middle value. It is the value that splits the dataset in half. To find the median, order your data from smallest to largest, and then find the data point that has an equal amount of values above it and below it. The method for locating the median varies slightly depending on whether your dataset has an even or odd number of values
median
139
is the value of observation that is midway along with the range. The arithmetic mean of the largest and smallest observation.
midrange
140
is the value that occurs the most frequently in your data set. It does not always exist.
mode
141
is the value that occurs the most frequently in your data set. It does not always exist.
mode
142
shows the scatterings of the data. It tells the variation of the data from one another and gives a clear idea about the distribution of the data.
measure of dispersion
143
is the total spread of the sample ranges from largest to smallest and vice versa
range
144
is defined as the average of the squared differences from the Mean.
variance
145
three steps to calculate the variance
(1) work out the Mean (the simple average of the
numbers), (2) then for each number: subtract the Mean and square the result (the squared
difference), and (3) then work out the average of those squared differences
146
is a measure of how spread out numbers are. It is the square root of the Variance.
standard deviation
147
It is called the root-mean-square
(RMS) error
standard deviation
148
are two terms that are commonly in surveying, however, their correct meaning is often misunderstood.
Accuracy and precision
149
indicates how close a given measurement is to the absolute or true value of the quantity measured. It implies the closeness between related measurements and their expectations.
Accuracy
150
refers to the degree of refinement and consistency
with which any physical measurement is made. It is portrayed by the closeness to one another of a set of repeated measurements of a quantity
precision
151
is defined as the number of times something will probably occur over the range of possible occurrences that involved in games of chance such as throwing dice, tossing a coin, or in various games using cards.
Probability
152
is based upon the following assumption relative to the occurrences of errors
theory of probability
153
is the arithmetic mean or the average. It
refers to a quantity which based on available data has more chances of being correct than has
any other. It can be calculated if redundant observations have been made. Redundant
observations are measurements above the minimum needed to determine the quantity
Most Probable Value (MPV)
154
is the value that is free from all the errors and this value is indeterminate
True Value
155
is the value obtained from the observation/measurement
Observed/Measured Value
156
refers to a quantity which based on available data has more chances of being correct than has any other
Most Probable Value (MPV)
157
is sometimes referred to as the deviation and defined as the difference between any measured value of a quantity and its most probable value
residual
158
is a quantity which, when added to and subtracted from the most probable value, defines a range within which there is a 50 percent chance that the true value of the measured quantity lies inside ( or outside ) the limits
Probable error
159
is expressed by a fraction having the magnitude of the error in the numerator and the magnitude of a measured quantity in the denominator
Relative precision
160
are used to control the sizes of corrections applied to observations in an adjustment. It is not always possible to obtain measurements of equal reliability under similar
conditions.
Weights
161
is the process of evaluating errors in quantities computed from observed values that contain errors
Error propagation
162
Two commonly applied principles of the theory of errors
Two commonly applied principles of the theory of errors
163
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
Summation of Errors
164
For a measured quantity that is determined as the product of two other independently measured quantities
Product of Errors
165
consists of counting the number of steps in a required distance. It furnishes a rapid
means of approximately checking more precise measurements of distance
Pacing
166
It is suitable for determining the approximate distance in a situation where a low precision of measurement is
insufficient.
Pacing
167
is sufficiently accurate for a reconnaissance survey, smallscale mapping, and locating details of a certain piece of land.
Distance by pacing
168
means moving with measured steps and if the steps are counted, distance can be determined if the length of the
step is known
Pacing
169
is defined as the length pf a step in walking. It may be measured from heel to heel or from toe to toe
Pace
170
is equivalent to two paces or double steps.
stride
171
The length of a pace will vary with the following factors:
1. Speed of pacing
2. Roughness of the ground
3. Weight of clothing and shoes used
4. Fatigue on the part of the pacer
5. Slope of the terrain
6. Age and sex of the individual
172
involves direct measurement of distances with measuring tapes. It consists of stretching a calibrated tape between two points and reading the distance indicated on the tape. It is the most common method of measuring or laying out horizontal distances
Taping
173
may vary from a relative precision of about 1:1000 to 1:25000 or better
Taping
174
are made in a variety of lengths, materials, and weights.
measuring tapes
175
measurement of shorter distances which are accumulated to total a full tape
length
breaking tape
176
are made directly along the slopes when the ground is of uniform inclination and fairly smooth, rather than break tape every few meters
Taped measurements
177
may be determined by running a line of levels between the terminal points and the angle of inclination may be obtained using theodolite or transit
difference in elevation
177
may be determined by running a line of levels between the terminal points and the angle of inclination may be obtained using theodolite or transit
difference in elevation
178
Taping operation could either be
(1) taping to determine an unknown length and (2)
taping to layout a required or specified length
179
common conditions that exist during taping operation that require the application of corrections are the following:
* The tape used is not of standard or nominal length.
* The ends of the tape are not held at the same level.
* Inaccuracy in keeping the tape along a straight line.
* The tape is not of nominal length due to the difference in temperature.
* Shortening or lengthening of the tape.
* Distance between the endpoints of an unsupported length of tape is less than
the specified nominal length.
180
due to inaccuracy in the alignment of tape is similar to the effect of slope and can be computed in the same manner It is, however, easier to control and the resulting error is much smaller in magnitude.
linear error
181
generally the least important among the different errors encountered in taping
Error due to alignment
182
The tape lengthens as the temperature rises and shortens as the temperature falls. Any
Correction due to Temperature
183
Correction due to Tension
The tape is subjected to a certain amount of standard pull or tension on its ends during
standardization.
184
is a function of the difference between the applied pull and the standard pull, the measured length, the cross-sectional area of the tape, and the modulus of elasticity of the tape material can be expressed as the ratio of unit stress to unit elongation
correction for the pull
185
is the applied pull which will the tape to equal the shortening caused by sag. It is the amount of pull required to make the endpoints coincide with the marked points on the pavement
Normal tension
186
is not necessarily limited only to the measurement of distances
tape
187
surveying operations
(1) erecting perpendicular to a line,
(2) measuring angles,
(3) laying off angles,
(4) determining obstructed distances,
(5) locating irregular boundaries, and
(6) determining areas of different shapes
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This surveying operation is commonly used in
floor dimensions of a building or a road intersection is to be laid out.
Erecting Perpendicular to Line.
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The tape is not frequently used in engineering construction for measuring or laying out angles. There are instances that the equipment used for measuring angles is not available that the tape is
instead used.
Measuring and Laying off Angles with Tape
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In some instances, it may not be possible to
directly measure distance due to an obstruction. The required length may also be inaccessible or difficult to measure.
Determining Obstructed Distances.
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Determining Obstructed Distances
By Right Angle, By Swing Offsets, By Parallel Lines and By Similar Triangles
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is another procedure of obtaining an indirect
measurement of horizontal distance. It is based on the optical geometry of the instruments
used.
Tachymetry
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It uses subtended intervals and angles observed with a transit or a theodolite on a
graduated rod or scale and having a relative accuracy of 1:300 to 1:400.
Tachymetry
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Tachymetric measurements are performed either
stadia method or the subtense bar method
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This method provides a rapid means of determining horizontal distances
Stadia Method
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is a convenient and practical device used for
a quick and accurate measure of horizontal distances
Subtense Method.
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The unknown distance may be determined through their relationship
distance geometrically by graphical and mathematical methods
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refers to the measurement of images on a photograph. The type of photographs used are those taken from an aircraft with the axis of the camera pointed vertically towards the terrain photographed
Photogrammetry
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is used to describe the collection of satellite positioning systems that are now operating or planned. Fixing of satellites to determine the position of the points.
Global Navigation Satellite Systems (GNSS)
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is the measurement of distance based on the invariant speed of light or electromagnetic waves in a vacuum. It is based on the principle that the time required for a radio or light wave to travel from one end of a line to the other is a function of the length measured.
Electronic Distance Measurement (EDM)
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Methods of Determining Distances
o Pacing
o Graphical and Mathematical Methods
o Taping
o Global Navigation Satellite Systems
o Mechanical Device
o Electronic Distance Measuring Equipment
o Tacheometry
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is the process or operation of directly or indirectly measuring vertical distances to determine the elevation of points or their differences in elevation
Leveling
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are undertaken to provide necessary data for engineering design and construction, and production of topographic maps. It can also be used for site suitability development
Leveling operations
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are undertaken to provide necessary data for engineering design and construction, and production of topographic maps. It can also be used for site suitability development
Leveling operations
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is a curved surface parallel to the mean spheroidal surface of the earth
Level surface
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is a line lying on a level surface
Level line
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is a plane that is tangent to a level surface at a particular point.
Horizontal surface
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is a straight line in a horizontal plane that is tangent to a level line at one point
Horizontal line
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is a vertical line at any point is a line parallel to the direction of gravity
Vertical line
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is the vertical distance above or below the mean sea level or any other selected datum
Elevation
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is the difference in elevation between two points is the vertical distance between the two-level surfaces in which the points lie
Difference in elevation
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is any convenient level surface coincident or parallel with mean sea level to which elevations of a particular area are referred
Datum
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is an imaginary surface of the sea which is midway between high and low tides
Mean Sea Level
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is a surface of constant potential energy (equipotential surface) that coincides with mean sea level over the oceans
Geoid
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is a mathematical surface of reference.
Reference Ellipsoid
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METHODS OF LEVELING
Direct or Spirit Leveling, Reciprocal Leveling, Profile Leveling, Trigonometric Leveling, Stadia Leveling, Barometric Leveling, Cross-Section Leveling, and Borrow-Pit Leveling
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is a method of determining the elevation of points some distance apart by a series of setups of a leveling instrument along a selected route. It
is also referred to as spirit leveling since the instrument used is a spirit level.
Direct or Spirit Leveling
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is commonly employed when leveling across a wide river, a deep ravine, or across canyons and gullies where it would be difficult or impossible to
maintain a foresight and a backsight distance of nearly equal lengths
Reciprocal Leveling
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is used to determine the difference in elevation between points at designated short measured intervals along an established line to provide data from which a vertical section of the ground surface can be plotted
Profile Leveling
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is employed in determining by trigonometric computations the difference in elevation between two points from measurements of its horizontal
and slope distance and the vertical angle between the points
Trigonometric Leveling
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combines features of direct leveling with those of trigonometric leveling. It is a form of trigonometric leveling
Stadia Leveling
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involves the determination of differences in elevation between points by measuring the variation in atmospheric pressure at each point utilizing altimeter or barometer
Barometric Leveling
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is often necessary to obtain a representation of the ground surface on either side of the centerline in highways or railroad constructions.
Cross-Section Leveling
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is a method of determining the relative elevations of points in borrow-pit excavations for calculating volumes of earthwork
Borrow-Pit Leveling
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is the process of determining the difference in elevation between two or more points some distance apart. It requires a series of setups of the instrument along a general route and, for each setup, a rod reading back to the point of known elevation and forward to a point of unknown elevation is taken
Differential Leveling
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Leveling Terms
Bench Mark ( BM ), Backsight ( BS ), Backsight Distance ( BSD ), Foresight ( FS ), Foresight Distance ( FSD ), Foresight Distance ( FSD ), Height of Instrument ( HI )
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is a fixed point of reference whose elevation is either known or assumed. It may be permanent (P.B.M.) or temporary (T.B.M.)
Bench Mark ( BM )
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is reading taken on a rod held on a point of known or assumed elevation
Backsight ( BS )
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is measured from the center of the instrument to the rod on which a backsight is taken
Backsight Distance ( BSD )
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is a reading taken on a rod held on a point whose elevation is to be determined
Foresight ( FS )
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is the horizontal distance from the center of the instrument to the rod on which foresight is taken
Foresight Distance ( FSD )
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is an intervening point between two bench marks upon which point foresight and backsight rod readings are taken to enable a leveling operation to continue from a new instrument position
Turning Point ( TP )
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is the elevation of the line of sight of an instrument above or below a selected reference datum. It is also determined by adding the rod reading
on the backsight to the elevation of the point on which the sight is taken
Height of Instrument ( HI )
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is the process of determining differences in elevation along a fixed-line at designated short measured intervals.
Profile leveling
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is a curved line that graphically portrays the intersection of a vertical plane with the surface of the earth
Profile
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is a numerical designation given in terms of horizontal distance any point along a profile line is away from the starting point
Stationing
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are also known as ground rod readings, are taken along the centerline of the proposed project to provide an accurate representation of the ground
surface. They are observed at regular intervals and at points where sudden changes in
elevation occur
Intermediate Foresights
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are points that are established along the profile level route at uniformly measured distances
Full Stations
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are points taken at breaks in the ground surface slope and critical points such as the intended location of culverts, bridges, and other structures
Plus Stations
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is a process of drawing the vertical scale for a profile much larger than the horizontal scale to accentuate the differences in elevation
Vertical Exaggeration
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is a special heavy grade graphing paper used for plotting profiles
Profile Paper
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The Procedure of Profile Leveling
* The line joining the initial and terminal points must first be established.
* A transit and tape survey is undertaken to start at the beginning of the line which is
designated as station 0+00.
* The instrument is set up at a convenient location and a backsight is taken on a reference
bench mark near the initial point to determine the height of the instrument.
* A series of intermediate foresight are next taken along the centerline to determine
elevations of ground points (done without transferring the instruments).
* A turning point is established if there is no longer possible to continue with the
foresight readings (regular intervals of 10 to 30 meters).
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Types of Levels
Dumpy Level, Wye Level, Builder’s Level, Automatic Level, Tilting Level, Geodetic Level, Transit as a Level, Laser Level, Hand Level, Digital Level
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is the most widely used direct leveling instrument. It has a long telescope which is rigidly attached to the level bar
Dumpy Level
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is identical to the dumpy level. The only difference is the telescope is attached to the supporting level bar
Wye Level
246
is often called a construction level or an architect’s level. The level vial is not as sensitive as in other levels and its telescope has a much lesser magnifying power
Builder’s Level
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is also termed as a self-aligning level. It is equipped with a prismatic device called compensator
Automatic Level
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consists of a telescope attached with a level tube which can be tilted within few degrees in a vertical plane by a tilting screw
Tilting Level
249
is employed in first-order leveling work where extreme precision is an important requirement
Geodetic Level
250
is also called a “universal surveying instrument” because of its variety of uses. There is no doubt that it can also be used for leveling work
Transit as a Level
251
is an innovation introduced to surveying operations is the use of lasers
Laser Level
252
is a handheld instrument used on surveys involving short sights and where a low order of accuracy is sufficient
Hand Level
253
uses electronic image processing to evaluate the special bar-coded staff reading
Digital Level
254
is a graduated rod that is used for measuring the vertical distance between the line of sight through a leveling instrument and the point whose elevation is either required or known
leveling rod
255
Leveling rods may be either
Leveling rods may be either
256
can be read directly by the instrument man through the telescope by noting the apparent
intersection of the horizontal hair on the rod
Self-reading rod
257
has a sliding target which is set and read by a rodman at the position selected by the instrument man
target rod
258
is a device used for fast and correct plumbing of a leveling rod. It is L-shape in design and consists of a small circular spirit level fastened to the rod or a small bracket held against the side of the rod
Rod level
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is a metal tube containing a system of lenses that are used to fix the direction of the line of sight and in magnifying the apparent size of the objects in its field of view
telescope
260
There are two types of telescope
internal focusing telescope and external focusing
telescope
261
has an additional auxiliary lens that moves back and forth between the objective and the crosshairs as the focusing screw it turned
Internal focusing telescope
262
has an objective lens mounted on a sleeve which moves back and forth in the telescope barrel as an object is brought into focus
external focusing telescope
263
is sealed graduated glass tube containing some amount of liquid and a small air bubble. It is used to determine the direction of gravity
level vial
264
serves as a base to prevent movement of the instrument after it is set up. It consists of three wooden or aluminum legs which are securely fastened the tripod head using a hinged joint
Tripod
265
Leveling the Instrument
Instrument with Four Leveling Screws and Instrument with Three Leveling Screws
266
Holding the Leveling Rod
* The leveling rod is held on a point by a rodman when sight is to be taken on it.
* The rod must be held plumb when the reading is made.
* The instrument man checks the rod by observing through the telescope and noting if
it is held parallel to the vertical crosshair.
* The fingers must not cover the face of the rod.
* The graduations of the rod are always clearly visible and not obstructed.
267
Taking a Rod Reading
Position the Rod, Focus on the Rod, and Read the Rod
268
Carrying the Instrument
* The level should always be kept in a box when it is not used.
* It should remain in its carrying case when transported to the worksite or when it has
to be moved to another distant setup or over rough terrain.
* The level does not detach from the tripod when transferring to another nearby station
provided that it is securely fastened to the tripod and is carried properly.
* In open spaces, the level may be carried on the shoulder in preferably a near-vertical
position.
* In densely forested areas, the level should be cradled between the arms and held
close to one’s chest left or right chest.
* The spindle is clamped slightly so that the telescope does not rotate when carried.
269
Sources of Error in Leveling
Instrumental Errors, Personal Errors, and Natural Errors
270
These errors are attributed to imperfections in the instruments either from faults in their manufacture or from improper adjustment
Instrumental Errors
271
Instrumental Errors
* Instrument out of adjustment
* Rod not standard length
* Defective tripod
272
It occurs largely due to the limitation of the senses of touch, sight, or hearing of individuals, the skills, training, and teamwork of the members of a leveling party
Personal Errors
273
Personal Errors
* Bubble not centered
* Parallax
* Faulty rod readings
* Rod not held plumb
* Incorrect setting of target
* Unequal BS and FS distances
274
These are errors that are due to natural sources and could not be removed but their effects can be reduced by applying corrections and using good
judgment
Natural Errors
275
Natural Errors
* Curvature of the earth
* Atmospheric refraction
* Temperature variation
* Wind
* Settlement of the instrument
* Faulty turning points
276
Common Mistakes in Leveling
* Misreading of the Rod
* Incorrect Recording
* Erroneous Computations
* Rod not fully Extended
* Moving turning Points
277
not always remain in perfect adjustment according to their manufacturer and keeping it in adjustment should always be given utmost consideration if
better results are desired
dumpy level
278
Adjustment of the Dumpy Level
Adjustment of the Cross Hairs, Adjustment of the Level Vial, and Adjustment of the Line of Sight
279
The reticule or the cross-hair ring is adjusted to see to it that the horizontal cross-hair lies in a plane perpendicular to the vertical axis of the
instrument
Adjustment of the Cross Hairs
280
The purpose of this is to make the axis of the level
perpendicular to the vertical axis of the instrument
Adjustment of the Level Vial
281
The line of sight is adjusted to make it parallel to the axis of the level vial. To check and adjust the line of sight, a procedure known as the “TWO-PEG” test is employed
Adjustment of the Line of Sight
