Using Legend

I have a 5 by 40 matrix and I’d like to plot 27 first columns as one color and last 13 columns as second color. My problem is that when i put legend to label each color, both legends are shown with the same color (always the same color as the first 27 columns). I appreciate your help. Thanks!

Answer 1

[Fangjun Jiang]

Look at the example in the document here. The legend should have the same color as they are used in the curve. What version of Matlab are you using?

[kate]

I read this page several time, here is a simple code that shows the problem:

x=[1 2 3 4 5 6;7 8 9 10 11 12;13 14 15 16 17 18]

figure

hold on

time=[1,2,3]

p=plot(time, x(:,1:4), 'b',...

time, x(:,5:6), 'r');

set(p, 'Linewidth',2);

legend('\fontsize{13} a', '\fontsize{13} b', 'Location', 'Best');

When you run it, the labels have the same color.

Don’t know where my mistake is. I appreciate any help.

I'm using Matlab 7.11.0 (R2010b).

Answer 2

[Fangjun Jiang]

In your example, if you have legend('a','b','c','d','e','f'), you'll have the right legend. The problem is that you have 6 curves, the first 4 are color blue and the last 2 are color red. You only made 2 legend marks thus it took the color of the first 2 curves (both are blue). Matlab legend() function is doing the right thing.

But, that is the problem you want to solve. Try this,

h=legend('a')
c=get(h,'Children')
set(c,'Color',[0 1 0])

You will see that it only makes one legend mark. Each legend mark will have three children (probably for line, marker and string). You can change the color for all of them by specifying the color as [Red Green Blue]. I believe this can solve your original problem.

[kate]

Thanks for the code, but how do i incorporate the second legend? it overwrite the color on the previous on. Should i define h as vectors?

How do we specify one color for each legend we produced?

Thanks a lot, any help is appreciated since I’m under too much pressure to figure things out as quickly as possible and I just started working with Matlab.

[Fangjun Jiang]

h=legend('a','b');

c=get(h,'Children');

set(c(1:3),'Color',[0 1 0]);

set(c(4:6),'Color',[1 0 0]);

Try to match them.

[kate]

It works now!

Thanks a million, you saved lots of time for me.

I really appreciate your help.