smoothing 2D plot in MATLAB

Question

I have some simple plot like this in MATLAB:

x = [0:5:25];
y = [1 4 7 9 8 3];
plot(x,y)

My question is how can I smooth it? Haven't found any way of doing what I want in documentation.

Answer 1

You can use a cubic smoothing spline

p  = 1e-2;           % initialize smoothing constant
fn = csaps(x, y, p); % get ppform of the cubic smoothing spline
y1 = ppval(fn, x);   % evaluate piecewise polynomial

For comparison:

plot(x,y);
hold on;
plot(x, y1, '-r');

Answer 2

Maybe you could make use of spline as follows

x1 = 0:.1:25;
y1 = spline(x,y,x1);
plot(x,y,x1,y1);