How to display only one legend for a figure with multiple plots?

Hello everyone,

I have two questions:

1) How can I display one unique legend for a figure with multiple plots?

2) Let assume 5,4,3, 2 and 1 as code for "very high", "High", "Moderate", "Low", and "Very Low" the values of my variable of interest. How can I display these characters strings instead of the value 5,4,3,2, and 1 in the legend?

Any thoughts for a code will be very much appreciated.

Armel

Answer 1

[Camilo Malagon Nieto]

I got a better solution that the one with b = get(gca,'Children')

From MatLab Documentation under Legend>Specify Charts to Include in Legend

x = linspace(0,3*pi); y1 = sin(x); p1 = plot(x,y1);

hold on y2 = sin(x - pi/4); p2 = plot(x,y2);

y3 = sin(x - pi/2); p3 = plot(x,y3); hold off

legend([p1 p3],'First','Third')

[hamid rafiei]

Dear

thanks for your answer

if I have a figure that saved as " .fig", how can I display one unique legend for a figure with multiple plots?

Thanks again

[Adam Danz]

See this answer below.

Answer 2

[Raghu S]

Here is the answer: menation these line inside legend command 'orientation','horizontal'

example: legend('orientation','horizontal','name1','name2','name3')

some example:

____________Mutiple legend:_______________

t=0:0.001:1;

sig1=2*sin(2*pi*10*t);

sig2=2*cos(2*pi*10*t);

subplot 212;plot(sig1);hold on;plot(sig2);legend('sin','cos')

subplot 211;plot(sig1);hold on;plot(sig2);legend('sin','cos')

____________Single legend___________________

legend('Location','bestoutside','orientation','horizontal','sin','cos')

One can move anywhere from the figure editor.

Attached one more example.

Answer 3

[Angus]

"legend('string1','string2',...) displays a legend in the current axes using the specified strings to label each set of data." ~ Matlab docs.

This is the simplest way of assigning strings to the legend. The docs show other uses.

When you say you have multiple plots, do you mean multiple axis or just multiple data plots within one axis? If you have multiple axis then you can create a unique legend that specifies what you want by using the second method from the docs:

"legend(h,'string1','string2',...) displays a legend on the plot containing the objects identified by the handles in the vector h and uses the specified strings to label the corresponding graphics object (line, barseries, etc.)."

[Angus]

Here is a crude example that I think illustrates the method.

Basically you need to get the handles for whichever objects you want in your legend, this can by done multiple ways and what I used is definitely not the best, just easy this time; you may want to use findobj(...) to get the handles if need be. Then choose a location for your legend and pass it the object handles and assign the strings. It is also possible to tidy things up by preparing the strings in an array, there are options for these things in legend().

x = [1:100];
y1 = sin(x);
y2 = 2*sin(x./2);
y3 = [1:100];
y4 = [100:-1:1];

subplot(121)
plot(x,y1,'b',x,y2,'r')
a = get(gca,'Children')

subplot(122)
plot(x,y3,'g',x,y4,'k')
b = get(gca,'Children')

h = [b;a]

legend(h,'decreasing','increasing','sine2','sine1','location','eastoutside')

My output: https://docs.google.com/file/d/0B851XTCKScHWNmNGVWRYeV9KdWs/edit?usp=sharing

[Armel]

In fact, here is a similar image that I would like to produce https://docs.google.com/file/d/0BwjZP-sfazLMS3JTVVJUTkdzNEE/edit?usp=sharing 2 (or many) images with only one legend but the images are raster data.

[Angus]

Yes, I saw that before, I'm not sure if raster data changes the method used. I'm not sure how raster data is dealt with in matlab, I dont use it. If you can get it to plot as in my example (convert it to a vector?) then this method should work for you.

Have I answered the original question about legends and multiple plots? Sorry I cant be much help with raster data use.

Cheers, Angus.

Answer 4

[Armel]

Hi Angus,

Thanks for your reply.

Is there a way to upload a similar figure so you will be able to understand what I mean?

Armel

P.S I'm new to this community

[Angus]

Hey, I am actually still new here as well. I am not sure if there is a standard method for linking images but I have seen some people upload via other websites like TinyPic.

Cheers, Angus.

Answer 5

[Adam Danz]

Update

Starting in Matlab r2020b, legends can be positioned relative to figure edges and can contain graphics objects from different subplots created by TiledLayout.

Examples:

• Example of a global legend in a 2x2 tiled layout
• Example of a global legend in a 1x4 tiled layout
• Example of a global legend in a 1x4 subplot