2. Basic Surveying

3. Introduction to Surveying Definition: Surveying is the science and art of determining the relative positions of points above, on, or beneath the earth’s surface and locating the points in the field.

4. 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, plat, or chart in the proper form. 5. Stakeout – locating and establishing monuments or stakes in the proper locations in the field.

5. 2 Categories of Surveying: 1. Plane Surveying – surveying with the reference base for fieldwork and computations are assumed to be a flat horizontal surface. Generally within a 12 mile radius the pull of gravity is very nearly parallel to that at any other point within the radius and thus horizontal lines can be considered straight. 2. Geodetic Surveying – surveying technique to determine relative positions of widely spaced points, lengths, and directions which require the consideration of the size and shape of the earth. (Takes the earth’s curvature into account.)

6. 7 Types of Surveys: 1. Photogrammetry – mapping utilizing data obtained by camera or other sensors carried in airplanes or satellites. 2. Boundary Surveying – establishing property corners, boundaries, and areas of land parcels. 3. Control Surveying – establish a network of horizontal and vertical monuments that serve as a reference framework for other survey projects. 4. Engineering Surveying – providing points and elevations for the building Civil Engineering projects.

7. 7 Types of Surveys: 5. Topographic Surveying – collecting data and preparing maps showing the locations of natural man-made features and elevations of points o the ground for multiple uses. 6. Route Surveys – topographic and other surveys for long – narrow projects associated with Civil Engineering projects. Highways, railroads, pipelines, and transmission lines. 7. Hydrographic Surveying – mapping of shorelines and the bottom of bodies of water. Also known as bathymetric surveying.

8. Brief History of Surveying: 1. 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 2. Greeks: expanded Egyptian work and developed Geometry. Developed one of the earliest surveying instruments – Diopter (a form of level).

9. Brief History of Surveying: 3. 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 4. 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.

10. Brief History of Surveying: 5. 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.

11. Brief History of Surveying: 6. 20 th 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 21 st century

12. Measurement of Distance Linear measurement is the basis of all surveying and even though angles may be read precisely, the length of at least one line in a tract must be measured to supplement the angles in locating points. Methods of measuring a horizontal distance: Rough Measuring: Pacing, Odometer readings, Tacheometry (stadia), Taping, EDM, and GPS Only the last three meet survey accuracy requirements Distance from stadia: (High wire-Low wire) * 100 = Distance (ft) More accurate measuring: taping, EDM (1966), GPS EDM and GPS are most common in today’s surveys In pacing, one establishes the # of paces/100’ by counting the # of paces over a pre-measured 300’ line

13. Measurement of Distance Taping: applying the known length of a graduated tape directly to a line a number of times. 2 Problems exist in Taping: 1. Measuring the distance between two existing points 2. Laying out a known distance with only the starting point in place

14. Measurement of Distance 6 Steps of Taping 1. Lining in – shortest distance between two points is a straight line. 2. Applying tension – rear chain is anchor and head chain applies required tension. 3. Plumbing – horizontal distance requires tape to be horizontal. 4. Marking tape lengths – each application of the tape requires marking using chaining pins to obtain total length. 5. Reading the tape – the graduated tape must be read correctly. 6. Recording the distance – the total length must be reported and recorded correctly.

15. Types of Chains and Tapes Before the ability to make steel rods and bands, sticks were cut into lengths of 16.5’ (Rod) and they were laid end to end to measure. Gunter’s Chain 66’ long with 100 link w/each link being 7.92 inches or 66 feet long Developed by Edmund Gunter in 1600’s in England and made with individual wires with a loop at each end connected Chain had between 600-800 wearing surfaces which with hard use would wear and cause chain to elongate Measurements were recorded in chains and links 7ch 94.5lk = 7.945 ch = 7.945 X 66’/ch = 524.37’ 1 chain = 4 rods; 80 chains = 1 mile

16. Types of Chains and Tapes Engineer’s Chain Same construction as Gunter’s Chain, but each link is 1.0’ long and was used for engineering projects Surveyor’s and Engineer’s Tapes Made of ¼” to 3/8” wide steel tapes in 100’; 200’; 300’ lengths Multiple types of marking and graduation: Available in chains, feet, and metric Graduated: Throughout – feet and tenths marked the entire length Extra foot – feet marked the length of the tape with additional foot at the 0 end graduated in tenths and hundreds of the foot

17. Types of Chains and Tapes Invar Tapes Made of special nickel steel to reduce length variations due to temperature changes The tapes are extremely brittle and expensive Used most of the time for standard comparison of tapes Cloth, Fiberglass, and PVC Tapes: Lower accuracy and stored on reels. Used for measurement of 0.1’ accuracy requirements Accessories 1. Chaining Pins – set of 11, used to mark the tape lengths 2. Hand Level – used to determine required plumbing height 3. Plumb Bob – used to transfer the mark from the tape to ground 4. Tension Handle – used to maintain correct tension on tape

18. 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

19. Stationing: Starting point is 0+00 and each 100’ is one station  700’ from starting point is Station 7+00 If distance is 857.23’ from starting point, it is expressed as Station 8+57.23

20. Taping Error: 1. Instrumental Error – a tape may have different length due to defect in manufacture or repair or as the result of kinks 2. Natural Error – length of tape varies from normal due to temperature, wind and weight of tape (sag) 3. 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.

21. Tape Error Correction: 1) Measuring between two existing points: 1) If a tape is long, the distance will be short, thus any correction must be added 2) If tape is short, the distance will be long, thus any correction must be subtracted 3) If you are setting or establishing a point, the above rule is reversed. Generally can correct for tape length, temperature, tension, and sag, but tension and sag are negated by increasing tension to approximately 25 – 30 lbs.