A method to express complex curves concisely and with high fidelity

Piecewise spline interpolation between judiciously selected points on a curve reproduces it with great precision. A number of points much smaller than in current digitization techniques is needed and their positions fully characterize a curve. We present the rules to select the nodal points and we demonstrate that their positions are very sensitive to changes in wave form. They can therefore be used to identify a curve in parts or in its entirety, to provide its mathematical definition.