Ryan Kruse

This is great! Thanks!

I made a slight modification to deal with NaN values. I changed this:
x = x(:);
y = y(:);
z = z(:);
w = w(:);

to this:
x = x(~isnan(z));
y = y(~isnan(z));
z = z(~isnan(z));
w = w(~isnan(z));