Site SurveyingUnit 1 - Introduction

DefinitionsPLOT: means the area of contiguous parcel of land enclosed by definite boundaries over which the applicant has legal right for developmentSITE: The place at which construction work is undertaken; a building site. An area of land designated by a planning application for a specific development, or one for which a proposed building is to be designed. LAND:an area or plot of ground on the earths surface. SURVEYING:Surveying is the science and art of determining the relative positions of pointsabove, on, or beneath the earths surface and locating the points in the field.

Short History of SurveyingSurveying had its beginning in Egypt about 1400 BCLand 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 monumentsGreeks: expanded Egyptian work and developed Geometry.Developed one of the earliest surveying instruments Diopter (a form of level).

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 organizationDeveloped several instruments:Groma cross instrument used to determine lines and right anglesLibella A frame with a plumb bob used for levelingChorobates 20 straight edge with oil in notch for levelingMiddle 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.

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 sections30 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 mappingFamous American Surveyors: George Washington, Thomas Jefferson, George Rogers Clark, Abe Lincoln and many more.

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 1990sCapable of electronic distance measurement, positioning using global positioning systems, construction machine control, and lidar (scanning) mappingInvolvement in rebuilding of the infrastructure and geographic information systems (GIS)Shortage of licensed professionals is projected well into the 21st century

The work of the surveyor consists of 5 phases:Decision Making selecting method, equipment and final point locations.Fieldwork & Data Collection making measurements and recording data in the field.Computing & Data Processing preparing calculations based upon the recorded data to determine locations in a useable form.Mapping or Data Representation plotting data to produce a map, plat, or chart in the proper form. Stakeout locating and establishing monuments or stakes in the proper locations in the field.

Categories of SurveyingPlane 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.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 earths curvature into account.)

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

7 Types of Surveys:Route Surveys topographic and other surveys for long narrow projects associated with Civil Engineering projects.Highways, railroads, pipelines, and transmission lines.Hydrographic Surveying mapping of shorelines and the bottom of bodies of water.Also known as bathymetric surveying.

Chain Surveying

Chain SurveyingSimplest method of surveyingMeasurements are taken in field and the rest work, such as plotting calculation etc. are done in officeMost suitable adapted to small plane areas with very few detailsCarefully done, gives accurate results.Necessary requirements : chain, tape, ranging rod, arrows and sometime cross staffSystem of surveying in which sides of various triangles are measured directly in the field and NO angularAdopted when level of accuracy required is not high.

ExecutionReconnaissance: The preliminary inspection of the area to be surveyed.Marking stations Reference sketchesRunning survey line

ApplicationChain survey is suitable whenGround is fairly level and simplePlans are required on large scale e.g., fieldsWhen area is small in extentChain survey is not suitable whenFor large areasWhen too many details are not requiredWooden countriesUndulating areas

Types of Chains and TapesBefore 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.GUNTERS CHAIN66 long with 100 link w/each link being 7.92 inches or 66 feet longDeveloped by Edmund Gunter in 1600s in England and made with individual wires with a loop at each end connectedChain had between 600-800 wearing surfaces which with hard use would wear and cause chain to elongateMeasurements were recorded in chains and links 7ch 94.5lk = 7.945 ch = 7.945 X 66/ch = 524.371 chain = 4 rods; 80 chains = 1 mile

Types of Chains and TapesSurveyors and Engineers TapesMade of to 3/8 wide steel tapes in 100; 200; 300 lengthsMultiple types of marking and graduation:Available in chains, feet, and metricGraduated: Throughout feet and tenths marked the entire lengthExtra foot feet marked the length of the tape with additional foot at the 0 end graduated in tenths and hundreds of the foot

Types of Chains and TapesEngineers ChainSame construction as Gunters Chain, but each link is 1.0 long and was used for engineering projectsInvar Tapes Made of special nickel steel to reduce length variations due to temperature changesThe tapes are extremely brittle and expensiveUsed most of the time for standard comparison of tapesCloth, Fiberglass, and PVC Tapes:Lower accuracy and stored on reels. Used for measurement of 0.1 accuracy requirements

AccessoriesChaining Pins set of 11, used to mark the tape lengthsHand Level used to determine required plumbing heightPlumb Bob used to transfer the mark from the tape to groundTension Handle used to maintain correct tension on tape

Gunters Chain

Modern ChainsModern chains are metal strips 100 feet long. These chains are three standard types.

Fully graduated2.First foot (cut chain)3.Extended foot (add chain)1.

Reading Surveying Steel ChainThe first step in reading a surveying chain is to determine the units that are used.

Knowing that the chain is 100 feet long, having numbers from 0 to 100 indicates that each number is one foot of distance.Each foot has nine (9) lines (10 spaces), therefore each line represents 1/10 or 0.10 of a foot.The reading for this example is 98.6 ft.Note: this a fully graduated chain

Reading A Cut ChainThe first foot or cut chain gets its name from the fact that the whole foot reading at the head of the chain must be reduced cut by the partial foot.

In this example the pin at the head is on 99 feet and the rear pin is on 0.4 feet. The distance is 99 - 0.4 or 98.6 feet.

Reading An Add ChainThe extended foot (add) chain gets its name because an additional foot is added to each end of the chain.The partial foot is added to the foot value at the head of the chain.In this example the head pin is on 99 feet an the rear pin is at 0.7 feet. The distance is 99 + 0.7 or 99.7 ft.

Steel chain on holderTo rewind chain on holder:Hold holder vertical in the left hand.Attach 100 foot end of the tape with the numbers up.Wind tape up rotating the handle clockwise.Remember to wipe tape with a dry cloth as it is wound onto the handle.

Triangulation

TriangulationA surveying method that measures the angles in a triangle formed by three survey control points.

Survey Instruments

TransitTransit 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.Components of the TransitAlidade Upper partHorizontal limb Middle partLeveling-head assembly Lower part

TransitALIDADE (UPPER PART)Circular cover plate w/2 level vials and is connected to a solid conical shaft called the inner spindle.Contains the vernier for the horizontal circleAlso contains frames that support the telescope called STANDARDSContains the vertical circle and its verniers, the compass box, the telescope and its level vialHORIZONTAL LIMB (MIDDLE PART)This is rigidly connected to a hollow conical shaft called the outer spindle (which holds the inner spindle)Also has the upper clamp, which allows the alidade to be clamped tightAlso contains the horizontal circle

TransitLEVELING-HEAD ASSEMBLY (LOWER PART)4 leveling screwsBottom plate that screws into tripodShifting device that allows transit to move to 3/8 ball that allows transit to tilt when being leveledThe SPIDER 4-arm piece which holds the outer spindleLower clamp allows rotation of outer spindle

Transit

Transit - PropertiesDesigned to have proper balance between:Magnification and resolution of the telescopeLeast count of the vernier and sensitivity of the plate and telescope bubblesAverage length of sight of 300 assumed in designSpecifications of typical 1 gun:Magnification 18 to 28XField of view - 1 to 130Minimum focus 5 to 7X-hairs usually are + with stadia lines above and belowThe transit is a repeating instrument because angles are measured by repetition and the total is added on the plate

Operation of Transit9 Steps:Set up over point B and level it. Loosen both motionsSet up the plates to read 0 and tighten the upper clamp. (Upper and lower plates are locked together)Bring Vernier to exactly 0 using upper tangent screw and magnifying glass.Sight on point A and set vertical X-hair in center of point, by rotating transitTighten the lower clamp and entire transit is locked inSet X-hair exactly on BS point A using the lower tangent screws. At this point the vernier is on 000 and the X-hairs are on BS

Operation of TransitLoosen the upper clamp, turn instrument to right until you are near pt. C. Tighten the upper clampSet vertical X-hair exactly on pt. C using the upper tangent screw.Read on vernierIf repeating , loosen lower motion and again BS on A (using only lower motion), and then loosen upper motion to allow to accumulate.If an instrument is in adjustment, leveled, exactly centered, and operated by an experienced observer under suitable conditions, there are only 2 sources for error.Pointing the telescopeReading the plates

TransitHANDLING A TRANSITHints on handling and setting-up the transitPick up transit by leveling head and standardsWhen carrying the transit, have telescope locked in position perpendicular to the leveling head with objective lens downWhen setting-up, keep tripod head level and bring plumb bob to within of point to be set over, then loosen leveling screws enough to enable you to move transit on plate, then move transit until it is over the point

ADVANTAGESBetter accuracy obtained through averagingDisclosure of errors by comparing values of the single and multiple readings

Telescope, ScalesTELESCOPE: Similar to that of dumpy level, but shorterParts objective, internal focusing lens, focusing wheel, X-hairs, & eyepiece

SCALES: Horizontal plate or circle is usually graduated into 30 or 20 spaces with graduations from 0 to 360 in both directions.Circles are graduated automatically by machine and then scanned to ensure accuracyThey are correct to with in 2 of arc

VernierLeast count = Lowest # of reading possible determines accuracyLeast Count = (Value of smallest division on scale)/(# of divisions on vernier)

Scale GraduationVernier DivisionsLeast Count30301204030154520106010

VernierThe vernier is always read in the same direction from zero as the numbering of the circle, i.e. the direction of the increasing anglesTypical mistakes in reading verniers result fromNot using magnifying glassReading in the wrong direction from zero, or on the wrong side of a double vernierFailing to determine the least count correctlyOmitting 10, 15, 20, 30 when the index is beyond those marks

Vernier3 Types of VerniersDirect or single vernier reads only in one direction & must be set with graduations ahead of zeroDouble vernier can be read clockwise or counterclockwiseonly is used at a timeFolded vernier avoids a ling vernier plate of the graduations are placed on each side of the index markUse is not justified because it is likely to cause errors.

Line of coincidentAngle scale with Vernier Vernier scaleMain scale readingMechanical instruments use Vernier scales to improve the precision of the instrument.The Vernier scale divides the last unit on the main scale into another set of fractional parts.The main scale is read at the zero (0) on the Vernier scale.The Vernier scale is read at the line of coincident.Reading of the scale : 26.5o

Double Vernier ScaleThe double Vernier is read using the same method.One additional step when reading a double Vernier is deciding which side of the Vernier should be read.This is determined by the direction of rotation of the instrument.[Note: the angle scale is stationary and the Vernier scale rotates] Clockwise rotation (right turned) = Left sideCounter clockwise rotation (Left turned) = Right sideRotation

Odometer WheelOdometer wheels use different units on the odometers.Insure you know the measuring units before you start to use the wheel.

Optical - Range finderRange finders are used to measure distance.Two primary types are optical and EDM.Optical range finders use lenses, mirrors and principles trig to determine distance.

Range finder - EDMEDM = Electronic distance measuringMany different models.Many different features.Many different prices. (Precision)PRINCIPLES OF EDMLaser light and other signals travel at the speed of light.If you know speed and time, you can calculate distance.Multiple signals are used to determine partial cycles.

Hand levelThis is the simplest type of hand level. It is useful for estimating slope & elevation changes.This instrument is called the Abney level. It can be used to measure slope, vertical angles and stadia distances.

RodThe Philadelphia style rod is seven (7) feet long and has a scale that measure to 1/100 of a foot.Each whole foot is marked with a large red number.A small red foot number is located at the 1/3 foot mark.The black numbers between each red foot mark are 1/10th of a foot.The 1/100ths are read by reading the transitions between white and black.

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Rod with TargetThe use of a target improves the accuracy of the readings and increases the readable distance between the rod and the instrumentUsing the Vernier scale on the target, distances can be read to 1/1000 of a foot.A rod with target can be used four ways.Direct readIndirect readHigh rodExtended rod

Dumpy (Wye) Level

Leveling a four (4) legged instrumentLeft thumb rule

Automatic LevelThese levels are called automatic because the level will complete the leveling process once it is close to level.

Total StationA total station is an electronic transit and an EDM combined into one instrument.Add in a microprocessor, laser plummet and other options and you have the instrument of choice for ground based surveying.Some may require a prism, but others are reflectorless.

Rocking the rodRocking the rod should be used when a rod level is not available.

Additional Equipment

Range poleSurveyors nailPlumb Bob

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