Determine the coordinates of an unknown point M (impossible to occupy) visible from two (2) previously surveyed reference stations A, B of a control baseline, only by observing angles α and β subtended by lines of sight from stations A and B to the intersected point M. Intersection technique is commonly implemented when the unknown point to be observed is inaccessible during a survey.

**Known** **values**: Angles a and b (observed), Reference stations' A, B coordinates.

**Solution**: Point M coordinates.

Adopting the clockwise lettering sequence, the coordinates of point M can be obtained directly from:

For maximum accuracy in the calculation of point M coordinates, the angle of intersection of lines of sight AM and BM must be between 60Â° and 120Â°.