Lesson 5: Mobile Mapping Fundamentals
Author: Nicolas R. Malloy
5.15 Triangulation versus Trilateration
Another common survey method used to extend horizontal control points is triangulation. Triangulation is a method of calculating distances using the geometry of triangles, where the length and angle of one or more sides is known. In this case, the known length, called a base, would be the distance between the control point and a second point. Distance to a third, or any number of additional points can be determined using the length of the base and the angle from the base to the third point. Using trigonometric law of sines, any number of additional triangles can be calculated.
What is triangulation? by Dr Chris Tisdell
Trilateration is another survey method that uses the geometry of triangles. This method uses only measured distances from point to point and the trigonometric law of cosines to find interior angles.