Legend of graph doesn't match plot color and style

Hello,

I have searched the forum and found some info regarding the legend color not matching the lines. However, I cannot get my head around the problem in my case where I have not only different colors, but also different line styles. Here is my code:

 inputNumber=3;
 figure
 hold on;
 plot(temps(1:25001,1,1),tempFrFilt(1:25001,1,1),'-b','linewidth',2);
 plot(temps(1:25001,2,1),tempFrFilt(1:25001,2,1),'-.b','linewidth',2);
 plot(temps(1:25001,3,1),tempFrFilt(1:25001,3,1),'--b','linewidth',2);
 plot(temps(1:25001,1,1),tempChFilt(1:25001,1,1),'-b','linewidth',2);
 plot(temps(1:25001,2,1),tempChFilt(1:25001,2,1),'-.b','linewidth',2);
 plot(temps(1:25001,3,1),tempChFilt(1:25001,3,1),'--b','linewidth',2);
 if inputNumber>1
    plot(temps(1:25001,1,2),tempFrFilt(1:25001,1,2),'-g','linewidth',2);
    plot(temps(1:25001,2,2),tempFrFilt(1:25001,2,2),'-.g','linewidth',2);
    plot(temps(1:25001,3,2),tempFrFilt(1:25001,3,2),'--g','linewidth',2);
    plot(temps(1:25001,1,2),tempChFilt(1:25001,1,2),'-g','linewidth',2);
    plot(temps(1:25001,2,2),tempChFilt(1:25001,2,2),'-.g','linewidth',2);
    plot(temps(1:25001,3,2),tempChFilt(1:25001,3,2),'--g','linewidth',2);
    if inputNumber==3
        plot(temps(1:25001,1,3),tempFrFilt(1:25001,1,3),'-y','linewidth',2);
        plot(temps(1:25001,2,3),tempFrFilt(1:25001,2,3),'-.y','linewidth',2);
        plot(temps(1:25001,3,3),tempFrFilt(1:25001,3,3),'--y','linewidth',2);
        plot(temps(1:25001,1,3),tempChFilt(1:25001,1,3),'-y','linewidth',2);
        plot(temps(1:25001,2,3),tempChFilt(1:25001,2,3),'-.y','linewidth',2);
        plot(temps(1:25001,3,3),tempChFilt(1:25001,3,3),'--y','linewidth',2);
    end
 end
 legend(cellstr(legendNames),'Location','southwest');

A picture can be found here:

What am I doing wrong?

Answer 1

[Chris]

The legend adds entries for each plot in the order that they were added to the current axes. If you want to change the order, or skip plots, you can do something like this:

P1 = plot( ... );
P2 = plot( ... );
P3 = plot( ... );
legend([P3, P1],'a label','another label')

The above example creates a legend for the third and first plot.

[Matt]

Thank you for your answer. I have renamed each plot, and replaced the legend command with the following, but it doesn't change anything:

legend([p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16, p17, p18], cellstr(legendNames));

It doesn't look elegant but I would think this would work. Again, the legend shows, but the colors are wrong. Styles ok but colors wrong.

[Chris]

What does your legendNames variable look like? At this point I'm thinking it might be formatted incorrectly. Another thing to try is

legend('-DynamicLegend')

which will automatically generate legend entries for each plot - check if the colours show up correctly there.

In regards to keeping the code more tidy, you could instead store your plots in an array, rather than separate variables.

[Matt]

The legendNames is a 1x9 cell variable containing the strings.

[Chris]

You'll need as many labels as you have plots. I'm assuming you want legend entries for each combination of linestyle and colour - in that case, try

legend([p1, p2, p3, p7, p8, p9, p13, p14, p15], cellstr(legendNames));

[Matt]

Thank you Chris, it did the trick! I've got it, but its a tricky one from Matlab.

[Chris]

Cheers, glad I could help!