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ENG 200 - Surveying Ron Williams
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Surveying The art of determining or establishing the relative positions of points on, above, or below the earth’s surface
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Determining or Establishing
Determining: both points already exist - determine their relative locations. Establishing: one point, and the location of another point relative to the first, are known. Find the position and mark it. Most property surveys are re-surveys determining you have no right to establish the corners
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History of Surveying First References
Dueteronomy 19:14 Code of Hannarubi Egyptions used surveying in 1400 b.c. to divide land up for taxation Romans introduced surveying instruments
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Surveying in America Washington, Jefferson, and Lincoln were survyors
The presence of surveyors meant someone wanted land - often traveled with soldiers Railroads opened up the country, but surveyors led the railroad East coast lands were divided by “Metes and Bounds”, the west by US Public Lands
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Types of Surveys Plane Surveys Assume NS lines are parallel
Assume EW lines are straight N Geodetic Surveys Allow for convergence Treat EW lines as great circles Used for large surveys
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Types of Surveys Land - define boundaries of property
Topographic - mapping surface features Route - set corridors for roads, etc. City - lots and blocks, sewer and water, etc. Construction - line and grade for building Hydrographic - contours and banks of lakes and rivers Mines - determine the relative position of shafts beneath the earth’s surface
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Safety Issues Sun Insects Traffic Brush cutting Electrical lines
Property owners
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Units of Measure Feet Meters Stations Inches, 1/4, 1/8, etc.
10’ 4-5/8” = 10.39’ Measure to nearest .01’ Meters 1 foot = m 1 m = 3.28’ Stations
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Units of Measure Rods - 16.5 ft Chains - 66 feet Miles - 5280 feet
4 rods = chain Miles feet 80 chains = 1 mile 320 rods = 1 mile Others
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Math Requirements Degrees, Minutes, Seconds Geometry of Circles
Trig Functions Geometry, Trig of Triangles
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° - ‘ - “ to Decimal Degrees
1 degree = 60 minutes 1 minute = 60 seconds 32°15’24” 24” = 24/60’ = 0.4’ 15’24” = 15.4’ = 15.4/60° = ° 32°15’24” = ° Most calculators do trig calculations using decimal degrees - CONVERT!
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Decimal Degrees to DMS = 23.1248° 23.1248° = 23°7’29.3”
0.1248*60 = minutes 0.488*60 = 29.3 seconds ° = 23°7’29.3” Watch roundoff! 23.1° = 23°6’00” We do most work to at least 1 minute! Cheap scientific calculator - $12.00
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Geometry of a Circle Total angle = 360°
23°18’ Total angle = 360° 4 quadrants - NE, SE, SW, NW - each total 90° NE SE SW NW Angles typically measured East from North or East from South Clockwise (CW) and Counterclockwise (CCW) angles add to 360° 360° - 23°18’ = 336°42’
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Geometry of a Circle N Transit sited along line AB, 105°15’ clockwise from North. C 135°42’ Transit is turned 135°42’ counterclockwise to site on C. A 105°15’ 224°18’ Determine the direction of line AC. 105°15’ - 135°42’ = -30°27’ Counterclockwise – angle gets smaller Negative result – add 360 -30°27’ + 360° = 329°33’ B Or: 360° - 135°42’ = 224°18’ 105°15’ + 224°18’ = 329°33’
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Trig Functions Sin, Cos, Tan are ratios relating the sides of right triangles o - side opposite the angle a - side adjacent to the angle a h h h - hypotenuse of triangle o h a o o Sin = o/h Cos = a/h Tan = o/a a
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Using Trig Functions Line AB bears 72°14’ East of North
Length of AB, lAB = ’ Determine how far North and how far East B is from A 72°14’ 375.46’ A B Cos = a/h, a = h*Cos NB/A = lAB * Cos(72°14’) = ’ 357.37 115.15’ Sin = o/h; o = h*Sin EB/A = lAB * Sin(72°14’) = ’
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Triangle Geometry, Trig Laws
Sum of interior angles = 180° Sine law: A B C if A = B, = Cosine law: if = 90°, A2 = B2 + C2
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