Determining Lat, Long using trigonometry

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SUMMARY

This discussion focuses on determining latitude and longitude coordinates using spherical trigonometry. The key points include the known coordinates of the True North Pole (90°N) and the Geomagnetic North Pole (82.7°N, 114.4°W), along with the distance between these two points (820.76 km). The participants explore the relationships between the angles and sides of the spherical triangle formed by these points, utilizing the law of sines to derive the coordinates of an unknown location (Point C). The discussion emphasizes the application of spherical trigonometric identities to solve for unknown variables.

PREREQUISITES
  • Spherical trigonometry concepts
  • Understanding of the law of sines
  • Knowledge of Earth's geometry and radius (6371 km)
  • Familiarity with latitude and longitude coordinate systems
NEXT STEPS
  • Study the law of sines in spherical trigonometry
  • Learn how to calculate distances on a sphere using spherical geometry
  • Explore spherical triangle identities on Wikipedia
  • Practice solving for unknown coordinates using known points and distances
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Mathematicians, geographers, navigators, and anyone interested in applying spherical trigonometry to determine geographic coordinates.

Insanity
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I am not sure if this is entirely possible, as my spherical trig skills are lacking.

Would it be possible to determine the Lat and Long coordinates for a position on the Earth knowing the following.

  1. True North Pole is at 90°N
  2. Geomagnetic North Pole is at 82.7°N, 114.4°W
  3. Knowing the direction of True North, I can determine the angle separating the two at my position.

The vertices of the spherical triangle would be.
  1. Point A would be the True North Pole.
  2. Point B would be the Geomagnetic North Pole.
  3. Point C would be my location.

The sides of the spherical triangle would be.
  1. Line AB, or γ
  2. Line BC, or α
  3. Line AC, or β

Side γ has a known length, the distance from the True Pole to GM Pole, which is 820.76km. With Earth's radius at 6371km, this works out to be 0.13 radians, or 7.38°.

sin C/sin γ = -1.07703 = sin A/sin α = sin B/sin β Correct?

Seems to me the other lengths should be able to be determined, and then perhaps the coordinates of Point C. Is that possible?
 
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Insanity said:
Side γ has a known length, the distance from the True Pole to GM Pole, which is 820.76km. With Earth's radius at 6371km, this works out to be 0.13 radians, or 7.38°.

sin C/sin γ = -1.07703 = sin A/sin α = sin B/sin β Correct?

Maybe I have the law of sines upside down?

C is the angle between vertices, γ is the length of the opposite side in degrees, so then

sin γ/sin C = -0.92848

I know the lat, long of two vertices, A and B, of the triangle, and the length of one side γ, and the angle of its opposite vertice C.
 

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