Surveying Triangulation Distance

Given baseline + 2 angles, find unknown distance via law of sines.

Inputs

Result

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General calculation reads

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How to use this calculator

  • Measure baseline + angles A and B.
  • Read distances to target.

About this calculator

Triangulation: measure a baseline + the angles to a distant point from each end. Law of sines computes distances to the point. Foundation of all classical surveying. Used to map territories before GPS. Modern GPS replaces it for most uses, but triangulation remains relevant for archaeology, terrestrial laser scanning verification, and astronomy (parallax to nearby stars). Source: standard surveying textbooks.

Frequently asked

Why measure baseline?+
Baseline gives length scale. Angles alone yield only proportions (similar triangles).
GPS vs. triangulation?+
GPS triangulates from satellites — same principle in 3D using time-of-flight not angles.
Errors?+
Small angle errors at long range cause big distance errors. Better baseline = better accuracy.
Stellar parallax?+
Same idea. Earth's orbit is baseline. Angle to star measured 6 months apart → distance.
Trilateration vs. triangulation?+
Trilateration: distances. Triangulation: angles. GPS uses trilateration with timing.

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