Interpolation Methods

Interpolation is the way to estimating a function at intermediate point. There are some methods of interpolation as I refer to Wikipedia:

1. Piecewise constant interpolation : locate the nearest data value and assign the same value.

Piecewise constant interpolation

2. Linear interpolation : taking the midway value between two data points into the a linear function.

Linear interpolation superimposed

3. Polynomial interpolation : is a generalization of linear interpolation by replacing interpolant with a polynomial of higher degree.

Polynomial interpolation plot

4. Spline interpolation : is an interpolation using low-degree polynomial in each intervals and chooses the polynomial pieces such that they fit smoothly together.

Spline intepolation plot