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

Asked by Armel on 10 Jun 2013

Latest activity Answered by Raghu S on 30 Aug 2018

515 views (last 30 days)

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

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4 Answers

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Answer by Raghu S on 30 Aug 2018

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.

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Answer by Angus on 10 Jun 2013

"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.)."

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Angus on 12 Jun 2013

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 on 12 Jun 2013

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 on 12 Jun 2013

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.

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Answer by Armel on 11 Jun 2013

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

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Angus on 11 Jun 2013

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.

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Answer by Camilo Malagon Nieto on 24 Apr 2018

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')

You are now following this question

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