Locate a target from a measured baseline and two sighting angles, using the law of sines.
Distance to target
How to use this tool
The distance between your two observing stations.
Measure the angle between the baseline and the target at each station.
Baseline, both angles and the unit.
Distance from each station and the perpendicular distance to the baseline.
Formula & worked example
A 100 m baseline with 60° at both stations puts the target 100 m from each station.
Limitations — read this before you rely on it
Plane geometry: valid for short ranges where Earth curvature is negligible. Assumes the target and both stations are in the same plane.
Frequently asked questions
Finding a point’s position from a known baseline and the angles to it from both ends u2014 the basis of surveying and navigation.
Distance from station A is the side opposite angle B, and vice versa. Both are shown.
The three angles of a triangle sum to 180°, so the third angle must be positive for a real triangle.
Very, if angles are precise. A 1° error at long range can move the target by metres, so use a good instrument.
Not for short baselines. For kilometre-scale surveying, geodetic corrections apply.