Survey Mathematics
PublicEssential formulas and calculations for traverse, areas, curves, and trigonometry
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Cards (8)
Latitude and Departure formulas?
Latitude (ΔN) = L × cos(Az) Departure (ΔE) = L × sin(Az) Memory aid: Lat = N/S = Cosine Dep = E/W = Sine — Ghilani Elementary Ch. 10
Closure error formula?
Error = √[(ΣLat)² + (ΣDep)²] Relative Precision = Error / Total Length Example: Error=0.05, Length=5000 Precision = 1:100,000 — Ghilani Elementary Ch. 10
Bearing to Azimuth conversions?
NE: Az = bearing angle SE: Az = 180° - bearing SW: Az = 180° + bearing NW: Az = 360° - bearing Back Az = Forward Az ± 180° — Kavanagh Ch. 6
Coordinate area formula?
Area = ½|Σ(Xi×Yi+1 - Xi+1×Yi)| (Shoelace / Cross-multiply method) Go around polygon, close to start. — Ghilani Elementary Ch. 12
Law of Cosines and Sines?
COSINES: a² = b² + c² - 2bc×cos(A) (Find side from 2 sides + included angle) SINES: a/sin(A) = b/sin(B) = c/sin(C) (Find parts from AAS, ASA cases) — Ghilani Elementary Ch. 2
Horizontal curve: Radius from Degree?
Arc definition: R = 5729.578 / D Chord definition: R = 50 / sin(D/2) — Ghilani Elementary Ch. 24
Horizontal curve: Tangent distance?
T = R × tan(Δ/2) Other formulas: L = R × Δ (radians) LC = 2R × sin(Δ/2) E = R × [1/cos(Δ/2) - 1] — Kavanagh Ch. 17
Slope to horizontal distance?
HD = SD × cos(vertical angle) VD = SD × sin(vertical angle) Or: HD = √(SD² - VD²) — Ghilani Elementary Ch. 6