MATLAB 7.9

Splines in Two Dimensions

This demonstration interpolates data with a cubic spline in 2 dimensions. It uses the MATLAB® SPLINE function. It does NOT use the Spline Toolbox™, which is a complete set of functions for B-splines and other piecewise polynomials of any degree.

Randomly pick eight points. Plot them.

n = 7;
x = rand(n,1);
y = rand(n,1);
plot(x,y,'.')
axis([0 1 0 1])

Interpolate the points with two splines by evaluating them with a finer spacing. Plot the interpolated curve with a red line.

t = 1:n;
ts = 1:1/10:n;
xs = spline(t,x,ts);
ys = spline(t,y,ts);
hold on
plot(xs,ys,'r');
hold off