How to set background color for specific x-values of plot in Matlab?

Question

Eg see below.

I'd like to color-code (in red) the years for which another independent timeseries is greater than 0.

Answer 1

You can use the patch() function to draw sqares wherever you want, and give it the color in RGBA format, using an A (alpha) of around 0.5 for example

Lets illustrate with an example:

x=1:0.1:10;
y=sin(x*2*pi);

box1=[1 1 2 2];
box2=[4 4 5 5];
boxy=[-1 1 1 -1]*max(y)*1.2;

plot(x,y)
patch(box1,boxy,[0 1 0],'FaceAlpha',0.2)
patch(box2,boxy,[1 0 0],'FaceAlpha',0.2)

ylim(1.1*[min(y) max(y)])