# MATLAB Language Interpolation with MATLAB Piecewise interpolation 1 dimensional

## Example

We will use the following data:

``````x = 1:5:50;
y = randi([-10 10],1,10);
`````` Hereby `x` and `y` are the coordinates of the data points and `z` are the points we need information about.

``````z = 0:0.25:50;
``````

One way to find the y-values of z is piecewise linear interpolation.

``````z_y = interp1(x,y,z,'linear');
`````` Hereby one calculates the line between two adjacent points and gets `z_y` by assuming that the point would be an element of those lines.

`interp1` provides other options too like nearest interpolation,

``````z_y = interp1(x,y,z, 'nearest');
`````` next interpolation,

``````z_y = interp1(x,y,z, 'next');
`````` previous interpolation,

``````z_y = interp1(x,y,z, 'previous');
`````` Shape-preserving piecewise cubic interpolation,

``````z_y = interp1(x,y,z, 'pchip');
`````` cubic convolution, z_y = interp1(x,y,z, 'v5cubic'); and spline interpolation

``````z_y = interp1(x,y,z, 'spline');
`````` Hereby are nearst, next and previous interpolation piecewise constant interpolations. PDF - Download MATLAB Language for free