There are a couple ways to do this. Using surf() seems to be the better way in general for lines.
x = [1,2,3,4,5,6,7,8,9,10];
y = [2,4,6,8,10,12,14,16,18,20];
t = [10,10,10,20,30,50,10,30,10,100];
h = surf([x(:) x(:)],[y(:) y(:)],[t(:) t(:)]);
set(h,'facecolor','none','edgecolor','interp');
set(h,'linewidth',3); % make it fat so it's easier to demonstrate
view(2); % only show 2-D view
colormap(jet(256)); % or pick whatever map you want
colorbar
In my opinion, it's always difficult to read these types of plots without making the line rather thick. Discerning small local color differences against a broad white background is difficult. Compare against the same color against inverted colors:
Then again, using an inverted background isn't really practical for a lot of output requirements. Just a thought.
