Curve Fitting:

Curve fitting is the procedure of construction of a curve flowing through a specified set of points either with best fit or exact fit criterion (Fig 5(a)). Curve fitting capture the trend of the data through assigning a single function across the whole range. Interpolation is also to build a curve through piecewise joining of two adjacent points through line entities (linear interpolation) or arc entities (circular interpolation) (Fig 5(b)).

In Various CAD/CAM applications, say an aerofoil cross-section, the displacement curves, in FEM application etc. the utilization of curve fitting and interpolation are inevitable. An interpolated shape of aerofoil by using arc and line elements has been illustrated in Figure 5(c).

             (1) Interpolation                                                    (2) Curve Fitting

                             (3)

A short overview of curve fitting is given below. Various curve fitting techniques are available such like Lagrangian interpolation, polynomial fitting, Newton divided difference method and splines etc.

Analytical equation fitting techniques might be classified broadly as best fit and exact fit techniques.