Elementary Surveying (Lessons 1-5)
Direct measurements
Are made by applying an instrument directly to the unknown quantity and observing its value, usually by reading it directly from graduated scales on the device
Loose-leaf notebooks
Are more popularly used. They are available in either single or double sheets.
Centimeter and millimeter
Are not commonly used in surveying. They a de suitable for small dimensions needed in laboratories where very precise but minute measurements are required.
Indirect measurements
Are obtained when it is not possible or practical to make direct measurements
Sketches
Are rarely made to exact scale, but in most cases they are made approximately to scale. They are drawn freehand and of liberal size.
City Surveys
Are surveys of the areas in and near a city for the purpose of planning expansions or improvements, locating property lines, fixing reference monuments, determining the physical features and configuration of the land and preparing maps.
Geodetic surveying
Are surveys of wide extent which take into account the spheroidal shape of the earth.
Surveying field notes
Constitute the only reliable and permanent record of actual work done in the field.
Topographic surveys
Determine locations of natural and artificial features and elevations used in map making.
Survey measurements
Direct and indirect measurements
Field Crews
Each student will be assigned to a 4 or 5 people crew.
Eratosthenes
Egypt, 230 B.C. (Next developments are now related to the determination of the size of the spherical earth), Founder of Geodecy. Developed the principle of the arc-measurement method. Determined the size of the Spherical earth; he made observations at the City of Alexandria and Syene (Aswan or Assuan).
Control surveys
Establish a network of horizontal and vertical monuments that serve as a reference framework for initiating other surveys.
Product of errors
For a measured quantity which is determined as the product of two other independently measured quantities such as Q1 and Q2 (with their corresponding probable error.
Hectare (ha)
For larger areas _____ is used.
Kilometer (km)
For longer distances ____ may be used and in measuring the sides of large tracts of land.
Square millimeters or square centimeters
For very small areas, ____ ____ __ _____ ____ is used.
Types of errors
Gross errors, systematic errors Random errors
Levelbook
Has both pages ruled in columns and has wider horizontal spacing than the field book.
Surveying
Has traditionally been defined as the science, art and technology of determining the relative positions of point above, on or beneath the Earth's surface or of establishing such points.
Summation of errors
If several measured quantities are added, each of which affected by accidental errors, 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.
International bureau of weights and measures
In May 20, 1875, a treaty was signed in Paris by representatives of 18 countries (13 from Europe, 4 from the American continent and 1 from the Middle East) which created a permanent ____________.
Angles, elevations, times, lines, areas and volumes
In surveying, measurements are usually concentrated on:
Satellite
Include the determination of ground locations from measurements made to satellites using GNSS receivers, or the use of satellite images for mapping and monitoring large regions of the earth.
Accuracy
Indicates how close a given measurement is the absolute or true value of the quantity measured.
Measures of variability
Indicates the degree or extent to which the scores in a distribution are spread out from the center.
Classification and sources of errors
Instrumental errors Natural errors Personal errors
Route Surveys
Involves 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.
Merchet
This was a device for measuring time and meridian. It was first used by the Chaldeans in about 4,000 B. C. It consisted of a slotted palm leaf through which to sight and a bracket from which a plumb bob was suspended. By sighting through the slot and past the plumb bob string, a straight line could be projected.
Compass
It was first introduced for use in navigation. Consists of a magnetized steel needle mounted on a pivot at the center of a graduated circle.
Sample variance
is the estimate of the population variance and for a large number of random samples, the values of s2 tends to o2.
Units of measurement
1. Linear, area and volume measurements 2. Angular measurements
Aristotle
4th Century B.C. Gave arguments that would support the hypothesis that the earth was spherical in shape:a.) the changing horizon as one travels in various directions (not seeing the same things S one changes its location); b.) the round shadow o the earth that was observed in lunar eclipses; c.) the observation of ship at sea where more (or less) of the ship is seen as the ship approaches (or goes away)
Pythagoras
6th Century B.C. Suggested that the earth was spherical in shape. (This suggestion was made on the basis that a sphere was considered a perfect form)
Homer
9th century B.C. (Early recorded thoughts indicated that) the earth was a flat disk supporting a hemispherical sky (with this view there would only be one horizon with the time and length of day being independent of location)
Blunder
A large mistake
Tabulations
A series of numerical values observed in the field are best shown in tabulated format.
Odometer
A simple device that can be attached to any wheel of known circumference and directly registers the number of revolutions of the wheel, then converts to distance. Surface distance=circumference X no. Of revolutions
Hydrographic surveys
Made to map shorelines and measure depths of bodies of water and flow of streams; sea surveying is associated with port and offshore industries and marine environment.
Surveyor
Making measurements and the subsequent computations utilizing them are basic and essential tasks of a ______.
Centesimal units
Many countries in Europe and the Middle East use the _____ where the grad is the angular unit. In this system the circumference of a circle (360 deg) is divided into 400 grads.
Length
May also refer to other linear dimensions such as width, depth, thickness, height or distance.
Pedometer
May be hand carried to register the number of paces
Passometer
May be strapped or attached to the leg to register a pace by impact each time either foot touches the ground.
Pacing
Means moving with measured steps; it consists of counting the number of steps, or paces, in a required distance
Categories of numerical descriptors
Measures of central tendency Measures of variability
Commonly used prefixes
Mega (1,000,000) Kilo (1,000) Hecto (100) Deca (10) Deci (0.1) Centi (0.01) Milli (0.001) Micro (0.000001) Nano (0.000000001)
Units in SI
Meter (m) for linear measure, the square meter (sq m or m2) for areas, the cubic meter (cu m or m3) for volumes and the radian (rad) for plane angles
Statistics
Numerical methods of describing data
Plane table
One of the oldest types of surveying instruments used in field mapping. It consists of a board attached to a tripod in such a way that it can be leveled or rotated to any desired direction.
Route surveys
Or alignment surveys, involves the determination of alignment, grades, earthwork quantities, in connection with the design, planning and construction of highways, railroads, pipelines, etc.
Methods of measuring distances
Pacing By other mechanical devices
Field book entries
Page numbers Lab title Field measurements/observations Calculations Weather conditions and ground cover
Mechanical counters
Pedometer Passometer
Land, boundary, property and cadastral surveys
Performed to determine the length and director of property lines and establish the positions of these lines o. Te ground by setting property corner markers
Construction surveys
Performed to lay out, locate and monitor public and private engineering works; provide line, grade, control elevations, horizontal positions, dimensions and configurations for construction purposes.
Explanatory Notes
Provide a written description of what has been done in the field.
Plane and geodetic
Surveys are divided into two general classification:
Geodetic surveying
Takes into account the true shape of the earth.
Libella
The Assyrians and Egyptians are believed to be the first users of the ______. The instrument had an A-frame with a plumb line suspended from its apex and was used to determine the horizontal.
Roman Groma
The Roman surveyors used the groma as an instrument for aligning or sighting points. By employing the groma two lines at right angles to each other could be established on the ground where it is set up.
Radian
The SI for plane angles. Is defined as an angle subtle des by an arc of a circle having a length equal to the radius of the circle.
Astrolabe
The ______ of Hipparchus is considered to be one of the best known of the measuring instruments that have come down from ancient times. The instrument had a metal circle with a pointer hinged at its center and held by a ring at the top and a cross staff, a wooden rod about 1.25 meters long with an adjustable cross arm at right angles to it. It was originally designed for determining the altitude of the stars.
Dioptra
The ______ which was perfected by Heron of Alexandria, was used in leveling and for measuring horizontal and vertical angles. An arm containing sighting apertures at either end could be rotated to any desired position on the disc.
Arithmetic mean
The average of the observations
International System of Units
The bureau of weights and measures promulgated in 1960 the _____ _____ ____ ____, generally known as SI.
Cubic meter, liter and milliliter
The common metric units for volume are:
Kilometer, meter, centimeter and millimeter
The common units for length are:
Plane surveying
The earth is considered to be a flat surface.
Conventional, ring or loose-leaf
The field notebook may be bound in any of three ways:
Meter
The international unit of linear measure. Originally, the _____ was defined as 1/10,000,000 of the earth's meridional quadrant.
Telescope
The invention of the _____ in 1907 is generally accredited to Lippershey.
Transit
The invention of the ______ is credited to Young and Draper who worked independently from each other sometime in 1830. Both men were able to put together in one instrument the essential parts of what has long been known as the universal surveying instrument.
Mode
The most frequently occurring value in the sample; a data set with two models is called bimodal
International Bureau of Sevres
The original international meter bar was deposited at the _______ ______ ___ _____, near Paris, France.
Head tapeman
The person responsible for the accuracy and speed of all linear measurements with tape.
Chief of party
The person who is responsible for the overall direction, supervision and operational control of the survey party.
Technician
The person who is responsible for use and operation of all electronic instruments required in a field work operation.
Utilitymen
The person whose duties are to render other forms of assistance needed by the survey party or as directed by the chief of party.
Axeman/lineman
The person whose duty is clear the line of sight of trees, brush and other obstructions in wooded country.
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.
Rear tapeman
The person whose duty is to assist the head tapeman during taping operations and in other related work.
Pacer
The person whose duty is to check all linear measurements made by the tapeman.
Flagman
The person whose duty is to hold the flagpole or range pole at selected points as directed by the instrumentman.
Recorder
The person whose duty is to keep a record of all sketches, drawings, measurements ad observations taken or needed for a field work operation.
Computer
The person whose duty is to perform all computations of survey data and works out necessary computational checks required in field work operation.
Aidman
The person whose duty is to render first aid treatment to members of the survey party who are involved in snake and insects bites, accidents and other cases involving their health, safety and well being.
Instrumentman
The person whose duty is to set up, level and operate surveying instruments such as the transit, engineer's level, theodolite, sextant, plane table and alidade and etc.
Rodman
The person whose primary duty is to hold the stadia or leveling rod when sights are to be taken on it.
Combination of the above
The practice used in most extensive surveys.
Computer rule
The so called ____ _____ in rounding off values should not be applied to measured quantities.
Instrumental errors, natural errors and personal errors
The soured of errors in surveying measurements are classified under the following three groups.
Degree
The unit of angle used in surveying is the ____ which is defined as 1/360th of a circle.
Square meter
The unit of area in sI. Areas of small tracts of land, floor areas of buildings and structures are measured in ____ ____.
Angular and linear measurements
The usual surveying type of measurement entail both:
Median
The value in the middle middle of n observations of n is odd; or the mean of the two middle values if n is even.
Liter, hectare, knot, day, hour and minute
There are certain units which are not part of SI but are still widely used.
Construction Surveys
These are surveys which 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.
As-built surveys
These document the precise final locations and lay-outs of engineering works and record any design changes.
Natural errors
These errors are caused by variations in the phenomena of nature such as changes in magnetic declination, temperature, humidity, wind, refraction, gravity and curvature o the earth.
Instrumental errors
These errors are due to imperfections in the instruments used, either from faults in their construction or from improper adjustments between the different part prior to their use.
Accidental errors
These errors are purely accidental in character.
Personal errors
These errors arise principally from limitations of the senses of sight, touch and hearing if human observer which are likely to be erroneous or inaccurate.
Chorobates
This instrument was designed for leveling work. It consisted of a horizontal straight-edge about 6 meters long with supporting legs and a groove 2.5cm deep and 1.5m long on top. Water is poured into the groove and when the bar is leveled so that water stood evenly in the groove without spilling, a horizontal line is established.
Systematic errors
This type of error is one which will always have the same sign and magnitude as long as field conditions remain constant and unchanged. Also called cumulative error.
Natural errors
Are errors caused by changing conditions in the surrounding environment.
Interrelationship of errors
Summation of errors and product of errors
Indirect measurement
When it is not possible to apply a measuring instrument directly to a quantity to be measured an _____ _____ is made. In this type of measurement, the observed value is determined by its relationship to some other known values.
Ring-type
Which consists of many metal rings passing through perforations in the pages, has the advantage over the conventional binding that the book opens quite flat and that the covers can be folded back against each other.
Residual
Which is sometimes referred to as the deviation, is defined as the difference between any measured value of a quantity and its most probable value.
Crew chief
Will be in charge of that particular lab and will be responsible for checking out and returning the equipment at the end of the lab session.
Instrumental errors
Are errors caused by imperfections in instrument construction or adjustment.
Personal errors
Are errors that arise due to limitations in human senses.
Commonly used relationships
1 hectare ( 10,000 sq m or 100 ares 1 are (100 sq m) 1 sq km ( 1,000,000 sq m or 100 hectares)
Mistakes
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.
Linear Units
1 kilometer (km) (1000 meters) 1 meter (m) (1000 millimeters) 1 millimeter (1000 micrometers) 1 micrometer (um) ( 1000 millimicrometers) 1 millimicrometer (mu) (1000 million micrometers) 1 meter (m) 10 decimeters 1 decimeter (dm) 10 centimeters 1 centimeter (cm) 10 millimeters
Field survey party
1-14 Chief of party Assistant chief of party Instrumentman Technician Computer Recorder Head tapeman Rear tapeman Flagman Rodman Pacer Axeman/lineman Aidman Utilitymen
Degrees, minutes and seconds
Are also acceptable for plane angles measured in SI.
Measurements
Are defined as observations made to determine unknown quantities
Observations
Are directly observed (or measured) quantities which contain random errors
Forestry Surveys
A type of survey executed in connection with forest management and mensuration and the production and conservation of forest lands.
Photogrammetric Surveys
A type of survey which makes use of photographs taken with specially designed cameras either from airplanes or ground stations.
Measures of central tendency
Aka measures of location, a recompiled statistical quantities that give an indication of the value within a data set that tends to exist at the center.
Industrial surveys
Aka optical tooling or optical alignment; involves making extremely accurate measurements for manufacturing processes where small tolerances are required; applications include ship building and aircraft assembly
Surveying
All surveying operations have the same basic characteristics - That of delineating a portion of the earth's surface or subsurface or of establishing the position or boundaries of some object upon it. 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.
Semicircumferentor
An early surveying instrument which was used to measure and lay off angles and establish lines of sight by employing peep sights.
Diopter
An instrument developed by the Greeks sometime in 130 B.C. And known to be their most famous surveying instrument. This was used for leveling, laying off right angles and for measuring horizontal and vertical angles.
Surveying measurements
Any _____ ______ is always subject to the imperfections of the instrument used and the different errors inherent in the process of obtaining the measurement.
Aerial
Are accomplished using either photogrammetry or remote sensing.
Mine Surveys
Are surveys which 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.
Sexagesimal units
Are the degree, minute and second.
Gross errors
Are the results of blunders or mistakes that are usually caused by misunderstanding the problem, carelessness, fatigue, missed communication or poor judgment.
Topographic Surveys
Are those surveys made for determining the shape of the ground and the location and elevation of natural and artificial features upon it.
Systematic errors
Are those that conform to physical laws and are dealt with mathematically using functional relationships or models; these errors tend to accumulate so they are sometimes called cumulative errors; also known as biases
Random errors
Are those that remain in measured values after all blunders are detected and removed and corrections for all known systematic errors have been applied; they are caused by factors beyond the observer's control and are dealt with mathematically using probability models; sometimes called accidental errors; also known as compensating errors
Cadastral Surveys
Are usually closed surveys which are undertaken in urban and rural locations for the purpose of determining and defining property lines and boundaries, corners and areas. These surveys are also made to fix the boundaries of municipalities, towns and provincial jurisdictions.
Numerical descriptors or statistics
Are values computed from a data set that are used to interpret the data's precision or quality
Specialized types of surveys
As - built surveys Construction surveys Control surveys Hydrographic surveys Industrial surveys Land, boundary, property and cadastral surveys Mine surveys Photogrammetric surveys Route surveys Topographic surveys
Surveying instruments
Astrolabe, telescope, transit, semicircumferentor, plane table, dioptra, Roman groma, libella, vernier, diopter, compass, Gunter's Chain, chorobates, Merchet
Pace factor
Average length of a pace
Ground, aerial and satellite
Broad classifications of surveys:
Types of surveys
Cadastral, city, construction, forestry, hydrographic, industrial, mine, photogrammetric, route, topographic
Computations
Calculations or one kind or another form large part of the work of surveying.
Magnetic Compass
Came into wide use during the 13th century for determining the direction of lines and in calculating angles between lines.
Direct measurements
Is a comparison of the measured quantity with a standard measuring unit or units employed for measuring a quantity of that kind. Some common examples of direct measurements are applying a wire or tape to a line, determining a horizontal or vertical angle with a transit, or fitting a protractor between two intersecting lines to determine the intersection angle.
True value
Is a quantity theoretically correct or exact value. The true value can never be determined
Probable error
Is a quantity which, 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 this set.
Geomatics
Is a relatively new term that is now commonly being applied to encompass the areas of practice formerly identified as surveying.
Vernier
Is a short auxiliary scale placed alongside the graduated scale of an instrument, by means of which fractional parts of the smallest or least division of the main scale can be determined precisely without having to interpolate.
Variance
Is a value by which the precision is given for a set of data
Standard deviation of the mean
Is computed from the standard deviation of the sample according to the following equation.
Error
Is defined as the difference between the true value and the measured value of a quantity.
Probability
Is defined as the number of times something will probably occur over the range of possible occurrences.
Stride
Is equivalent to two paces or a double step.
Surveyor's Role
Is primarily to design a survey, then plan out and execute the required field operations.
Surveying by Webster
Is that branch of applied mathematics which traces the art of determining the area of any portion of the earth's surface, the length and directions of the boundary lines, the contour of the surface, and if accurately delineating the whole on paper.
Plane surveying
Is that type of surveying in which the earth is considered to be a flat surface and where distances and areas involved are of limited extent that the exact shape of the earth is disregarded.
Most probable value
Is that value for a measured quantity which, based on the observations, has the highest probability of occurrence
Discrepancy errors
Is the algebraic difference between two observations of the same quantity; a small discrepancy indicates there are probability no mistakes and random errors are small but does not preclude the presence of systematic errors
Surveying by Rayner and Schmidt
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.
Surveying by Clarke
Is the art of making such measurements of the relative positions of points on the surface of the earth that, in drawing them to scale, natural and artificial features may be exhibited in their correct horizontal or vertical relationship.
Surveying by Davis, Foote, Anderson and Mikhail
Is the art of measuring horizontal and vertical distances between objects, of measuring angles between lines, of determining the direction of lines and of establishing points by determined angular and linear measurements.
Error
Is the difference between a measured (observed) value for a quantity and its true value.
Residual
Is the difference between any individual measured quantity and the most probable value for that quantity; though very similar and behave in the same manner as errors, there is this theoretical distinction.
Range
Is the difference between the highest and the lowest values
Accuracy
Is the measure of absolute nearness of an observed quantity to its true value; since true value of a quantity can never be determined, accuracy is always unknown.
Measurement
Is the process of determining the extent , size or dimensions of a particular quantity in comparison to a given standard.
Rounding of a value
Is the processes of dropping one or more of the final digits so that the value contains only the significant figures required for further computation or for portraying the final results.
Surveying by Brinker and Wolf
Is the science and art of determining relative positions of points above, on, or beneath the surface of the earth, or establishing such points.
Surveying by Breed, Hosmer and Bone
Is the science or art of making such measurements as are necessary to determine the relative position of points above, on, or beneath the surface of the earth, or to establish such points.
Standard error
Is the square root of the population variance; the larger the standard error, the more dispersed are the values in the data set and the less precise is the measurement.
Standard deviation
Is the square root of the sample variance; a common measure of precision - lower standard deviation, higher precision. Is an estimate of the standard error of the population.
Steradian
Is the supplementary unit of a solid angle ( one which has its vertex in the center of a sphere which cuts off an area of the surface equal to the radius of the sphere).
Cubic meter
Is used for larger volumes which are common in engineering constructions and in measuring various quantities in surveying.
Hydrographic Surveys
Refer to surveying streams, lakes, reservoirs, harbors, oceans and other bodies of water.
Most probable value (mpv)
Refers to a quantity which, based on available data, has more chances of being correct than has any other.
Precision
Refers to the degree of refinement and consistency with which any physical measurement is made.
Precision
Refers to the degree of refinement or consistency of a group of observations and is evaluated on the basis of discrepancy; small discrepancies indicate high precision
Europe, Middle East, Africa and Asia
SI units are now adopted by most countries in:
Angular measurements
Sexagesimal units and centesimal units
Types of notes
Sketches, tabulations, explanatory notes, computations and combinations of the above
Relative error
Sometimes called relative precision, is expressed by a fraction having the magnitude of the error in the numerator and the magnitude of a measured quantity in the denominator.
Industrial Surveys
Sometimes known as optical tooling. It refers to the use of surveying techniques in ship building, construction and assembly of aircraft, layout and installation of heavy and complex machinery, and in other industries where very accurate dimensional layouts are required.
Gunter's Chain
This was invented by Sir Edmund Gunter in 1620, was the forerunner of instruments used for taping distances. It is 66 ft long and contains 100 links, so that distances may be recorded in chains and in decimal parts of the chain. Each part, called a link, is 0.66 ft or 7.92 inches long.
Information found in field notebooks
Title of the field work or name of the project Time of the day and date Weather conditions Names of group members and their designations List of equipment
Geodetic surveying and plane surveying
Two general classifications of surveys:
Systematic errors and accidental errors
Types of errors
Ground
Utilize measurements made with ground-based equipment such as automatic levels and total station instruments.
Mine surveys
Utilizes the principles for control, land, geologic and topographic surveying to control, locate and map underground and surface works related to mining operations
Photogrammetric surveys
Utilizes the principles of aerial and terrestrial photogrammetry