Fundamentals of Surveying Unit 1 PDF

Fundamentals of Surveying TCS110 - Surveying Level 1 Unit 1  TCS110 - Surveying Level 1 Topics in Unit 1 Introduction to Land Surveying -What is Land Surveying - Define Surveying - Who is a survey...

Fundamentals of Surveying TCS110 - Surveying Level 1 Unit 1  TCS110 - Surveying Level 1 Topics in Unit 1 Introduction to Land Surveying -What is Land Surveying - Define Surveying - Who is a surveyor Work Phases of a Surveyor – Uses of Surveying. History and Evolution of Surveying. Fundamental Principles of Surveying Understand metric and imperial units of measurement. Errors in Surveying -types of errors. Professional Ethics in Surveying Surveying Instruments  TCS110 - Surveying Level 1 Concept of land surveying Introduction: Having a land survey done is important before you start on any sort of construction work, such as on a building, plant or road. A land survey will help determine the optimal site for any structure according to topographical details, and identify potential issues such as whether the area is prone to flooding. Furthermore, land surveys are crucial in identifying and mapping surface contours, as well as existing surface features, buried utilities, and property lines. Having a land survey done beforehand is a vital step in protecting your investment for the future.  TCS110 - Surveying Level 1 Concept of land surveying Who is a Land surveyor, and what does he do? A land surveying professional is called a land surveyor who uses various elements of geometry, trigonometry, physics, engineering, and the law. They also work with equipment such as total stations, theodolites, levels, handheld tablets, drones, surveying software, etc. Registered Professional Land Surveyor, has the knowledge and capabilities to provide expert witness testimony. Their job is to measure and map land correctly.  What is Surveying ??? The art and science of measuring distances, angles & positions, on or near the surface of the earth. Why it is an art? Only a Surveyor who possesses a thorough understanding of surveying technique will be able to determine the most efficient methods to get the right results. Why it is scientific? Because the use of mathematical techniques to analyze field data, accuracy and reliability depends on understanding scientific principles underlying and affecting survey measurement.  The Work Phases of a Surveying The work of the surveyor consists of 5 phases: 1* Decision Making – selecting method, equipment and final point locations. 2* Fieldwork & Data Collection – making measurements and recording data in the field. 3* Computing & Data Processing – preparing calculations based upon the recorded data to determine locations in a useable form. 4* Mapping or Data Representation – plotting data to produce a map, plot, or chart in the proper form. 5* Stakeout – locating and establishing monuments or stakes in the proper locations in the field.  Primary Object of Surveying Object of Surveying The primary objective of survey is the preparation of plan of properties or buildings roads, railways, pipelines, canals, etc. Or to measure area of field, state, nation. Object of geodetic surveying is to determine precise positions on the surface of the earth of widely distant points.  What are the uses of Surveying 1. To prepare topographical maps which shows the hills, valleys, rivers, village towns, forest, etc. of a country. 2.To prepare cadastral maps to show the boundaries of field, houses and other properties. 3.To prepare engineering amaps to show the details of engineering works such as roads, railways, reservoirs, canals etc. 4. To prepare a military map to show the road and railway communications with different parts of a country. Such a map also shows the different strategic points important for the defence of a country. 5. To prepare contour maps to determine the capacity of a reservoir and to find the best possible routes for roads, railways, etc.  Brief History of Surveying Brief History of Surveying: Surveying had it’s beginning in Egypt about 1400 BC Land along the Nile River was divided for taxation. Divisions were washed away by annual floods. “ROPE-STRETCHERS” Egyptian surveyors were created to relocate the land divisions (measurements were made with ropes having knots at unit distances). Extensive use of surveying in building of Egyptian monuments Greeks: expanded Egyptian work and developed Geometry. Developed one of the earliest surveying instruments – Diopter (a form of level).  Brief History of Surveying Romans: developed surveying into a science to create the Roman roads, aqueducts, and land division systems. Surveyors held great power, had schools and a professional organization Developed several instruments: Groma – cross instrument used to determine lines and right angles Libella – “A” frame with a plumb bob used for leveling Chorobates – 20’ straight edge with oil in notch for leveling Middle Ages: Land division of Romans continued in Europe. Quadrans – square brass frame capable of turning angles up to 90° and has a graduated scale developed by an Italian named Von Piso  Brief History of Surveying 18th & 19th Century in the New World: the need for mapping and marking land claims caused extensive surveying, especially by the English. 1785: United Stated began extensive surveys of public lands into one mile square sections 30 states surveyed under the U.S. Public Land System (also called the Rectangular System) 1807: United States Geological Survey founded to establish an accurate control network and mapping Famous American Surveyors: George Washington, Thomas Jefferson, George Rogers Clark, Abe Lincoln and many more.  Brief History of Surveying.20th Century and Beyond: As technology advanced, population increased, and land value caused development of licensure for surveyors in all states. Educational requirements for licensure began in the early 1990’s Capable of electronic distance measurement, positioning using global positioning systems, construction machine control, and lidar (scanning) mapping Involvement in rebuilding of the infrastructure and geographic information systems (GIS) Shortage of licensed professionals is projected well into the 21st century.  Principles of Surveying In general, surveying is based upon a number of principles (or guidelines) a. Working from Whole to Part b. Economics of Accuracy c. Consistency of Work d. Independent Check e. Reconnaissance and Planning  Principles of Surveying Working from whole to part: This means that when an area is to be surveyed, first of all, a system of control points is established such that it covers the entire area with a higher degree of precision. After this, the minor control points and details are further established with a lesser degree of precision. Accuracy Required: The proper method and instrument must be used for the survey work on the basis of the degree of accuracy required. Consistancy: It must be noted that keeping consistency in the method, instrument, reading and noting observations, etc helps to gain the desired level of accuracy. Independent Check: every measurement that is taken in the field must be re- checked by adopting a suitable method of independent field tests and observations so that any mistake if present is not passed without notice. Metric Imperial Kilometre(km) Mile(mi) Metre(m) Yard(yd) Centimetre(cm) Foot(ft) Millimetre(mm) Inch(in) 1 km = 1,000m 1m = 0.001km 1 ft = 0.3048m 1m = 100cm 1cm = 0.01m 1m = 1000mm 1mm = 0.001m  Errors No measurement (except count) can be free of error. True value is determined statistically (mean) to calculate error. Systematic error: error whose magnitude and algebraic sign can be determined and eliminated (Example temp. error on a steel tape). If the temp. is known, then the shortening and lengthening of a tape can be determine.  Errors Random Error: Error due to surveyor skills and vigilance. Random errors are introduce in measurements because no human being can perform perfectly. - Tend to cancel each other. - Little significance except for high precision survey. - Unskilled or careless surveyor can make problem. - Large random error doesn’t result in accurate work even if they cancel.  Errors Mistakes-There are many mistakes that could happened to surveyors. - Blunders made by survey personnel e.g. 68 instead of 86. - Miscounting tape length, measuring from wrong point. - Mistakes will occur and must be discovered and eliminated by verifying the measurement (Repeat Geometry analysis, etc.). - Every measurement should be repeated to eliminate mistakes and improved precision.  Accuracy and Precision Accuracy is the relationship between the value of a measurement and the “true” value of the dimension being measured. Precision describes the refinement of the measuring process and the ability to repeat the same measurement with consistently small variations in the measurements (i.e., no large discrepancies). Accuracy and Precision  Professional Ethics in Surveying A “profession” is defined as “an occupation requiring advanced academic training, as medicine, law, etc.” (Webster’s New World Dictionary) Therefore, a “professional” is a member of such a profession. A “professional” is a person, who is a member of a professional body due to the education qualification and follows the prescribed moral and professional code of conduct. (thelawdictionary.org/professional)  Professional Ethics in Surveying What is Ethics?? “code of morality: a system of moral principles governing the appropriate conduct for a person or group.” (General web- based definition) “Ethical practice, simply put, is doing the right thing at the right time.” (Guy, 1990) “the science of moral duty or conforming to professional standards of practice.” (Illinois Professional Land Surveyors Association) “Ethics includes that branch of a moral science concerned with the duties members of the profession owe to their public, their professional associates, and their clients.” (Evidence and Procedures for Boundary Location) “… whatever you wish that others would do to you, do also to them …” (Matt. 7:12 ESV)  Professional Ethics in Surveying What is Ethics?? In the British Virgin Island Surveyors are guided by. Land Surveyors Ordinance. Land Surveyors Regulations. Planning Authority Guidelines. Condumainium. Land registry Professional Ethics in Surveying Some Principles of Being a Professional. The surveyor has the following obligations to the public: (1) to see that the client's boundaries are properly monumented without subtracting from the rights of the adjoiner; (2) not to initiate boundary disputes; (3) not to aid in unauthorized surveying practice; (4) to see that those licensed to survey are properly qualified by character, ability, and training; (5) to see that those who prove unworthy of their privileges have those privileges deprived; (6) to agree not to attempt to practice in any professional field in which one is not proficient; and (7) to produce a quality product regardless of the price.  Steel Tape  Theodolite  Total Station  Level & Rod  Satellite Positioning Receiver (GPS) Steel Tape Used for measuring the straight line between two points. Manufactured in both foot and metric units. Come in different lengths (100 ft, 200ft, ect. or 20m, 30m, 100m ect.  Steel Tape Tape end loops and Zero points Steel Tape vs Fibreglass Tape Fibreglass Tape Lighter Flexible Less likely to break Rust-Free & Rot-proof Tend to stretch more when pull Mostly Graduated in centimetres  Taping (Field Process) The line to be taped should be marked at both ends Keeps measurement on line Rear chain person should keep the head chain person on line 1’ of line error/100’ = 0.01’ error in length Applying Tension Rear chainman is anchor and should hold 100’ mark over point Tension is applied by head chain person – normally 12 to 30 pounds of pull Tapes are standardized at 12 lbs., but greater is utilized to compensate for sag  Taping (Field Process) Plumbing One end of tape is raised to maintain a horizontal measuring plane. ONLY one end is elevated. This allows measurements to be made on uneven ground If a high spot exists in center, “break” tape by measuring to the top and then move forward to complete the distance.  Slope Measurements: Generally, measurements are made horizontally, but on even, often man-made slopes the distance can be measured directly on the slope, but the vertical or zenith angle must be obtained. Horizontal Distance = sin Zenith Angle X Slope Distance. Horizontal Distance = cos Vertical Angle X Slope Distance.  Taping Error Instrumental Error – a tape may have different length due to defect in manufacture or repair or as the result of kinks Natural Error – length of tape varies from normal due to temperature, wind and weight of tape (sag) Personal Error – tape person may be careless in setting pins, reading the tape, or manipulating the equipment Instrumental and natural error can be corrected mathematically, but personal error can only be corrected by remeasure. When a tape is obtained, it should either be standardized or checked against a standard. Tapes standardized at National Bureau of Standards in Maryland Standardized at 68 degrees F and 12 lbs. tension fully supported.  Theodolite / Transit Vernier Theodolite Optical Theodolite Electronic Theodolite  Theodolite / Transit Transit is the most universal of surveying instruments – primary use is for measurement or layout of horizontal and vertical angles – also used to determine vertical and horizontal distance by stadia, prolonging straight lines, and low-order leveling. 3 Components of the Transit Alidade – Upper part Horizontal limb – Middle part Leveling-head assembly – Lower par Vernier Theodolite Optical Theodolite Electronic Theodolite  Theodolite Vernier Theodolite Optical Theodolite Electronic Theodolite Staff Theodoli te Reading distance with a theodolite & Staff  Total Station A combination of the electronic theodolite and electronic distance measurement (EDM). Has a central processor which enables the computation of horizontal and vertical distance. The central processor monitors the instrument status and executes software programs for a variety of survey applications. Data can be stored onboard or a data receiver.  Total Station Auxiliary Equipment Required Targets or Prisms to accurately define the target point of a direction measurement. A data recorder if one is not integrated into the total station. A download cable and software on a PC to capture and process the captured digital data to produce contour and detail maps  Total Station Factors influencing the use of Total Stations: A clear line of sight between the instrument and the measured points is essential. The precision of the instrument is dependent on the raw repeatabilities of the direction and distance measurements. A well defined measurement point or target/prism is required to obtain optimal precision and accuracy. The accuracy of direction and distance measurement is subject to a number of instrumental errors and the correct field procedures.  Robotic Total Station Display at target also, No need of operator on station, Moves automatically to predetermined direction and focuses automatically at target at specified distance, Can be integrated with GPS also.  Level and Rod Level and Rod used to determine elevations in a wide variety of surveying, mapping, and engineering applications Digital Level Automatic Level Tilting Level Level and Rod  Global Positioning Systems (GPS) Developed in early 1980’ s (Dept. of Defense) Made up of 26 satellites (24 functioning & 2 spares) Each satellite is 20,000 km high (off Earth’s surface) Each satellite is in a fixed position Minimum of 3 satellites needed, but 4-5 preferred Need satellites at least 15° above horizon Locate positions on Earth by distance-distance intersection Need 2-3 receivers ($80-$100K per system) Most accurate with double occupancy (no other checks) Differential GPS – one receiver on known point, other receiver on unknowns.  Global Positioning Systems (GPS) Biggest advantage Distance and direction in-between 2 points without being seen Downfalls/Limitations of GPS Multipath – bouncing off of walls of buildings Blocked signals – clouds, trees, etc. Sunspot – defraction from atmosphere DOP (Delusion of Position) – bad satellite position Set up error – not set up exactly over point (human error – most common  Satellite Positioning Receiver Captures signal by 4 or more satellites in order to determine position. (Easting, Northing and Elevation) Satellite Positioning Receiver  Satellite Positioning Receiver The more signals a GPS receiver can see (Spread apart versus close together), the more precise it can be. Poor GDOP Good GDOP (Geometric Dilution Of Precision)