Plotting legends in loop for mean and standard deviation of spectra

Question

ardeshir moinian 2021-1-14

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/717178-plotting-legends-in-loop-for-mean-and-standard-deviation-of-spectra

评论： Matt Gaidica 2021-1-15

I have mean values for my spectra and their standard deviation saved as

meanC=mean(C)
stdC=std(C)

the labels for my C data are saved as labelC

wavenumbers1 is the x axis of my data.

I wand to plot the mean spectra(meanC) vs wavenumbers and I want each spectrum to have a legend. I also want to plot the meanC+std and meanC-std as a shaded area around each mean. But I want to get the legend of the standard deviation curve only one time since it's the same color for all means. How should I go about this?

at the moment since I am using a loop, I get half of the legends of the mean spectra in my plot.... should I turn off the legends for the standard deviation? how would I do that using patch?

I am open to doing this with other functions if it's more efficient that way! I'm using Matlab R2018a

Thank you!

for i=1:M;
    plot(wavenumbers1,(meanC(i,:)); legend(labelC)
    hold on
    patch([wavenumbers1' fliplr(wavenumbers1')], [((meanC(i,:))+stdC(i,:)) fliplr((meanC(i,:))-stdC(i,:))], 'r', 'FaceAlpha',0.5, 'EdgeColor','none')
    
end

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Answer 1

Matt Gaidica 2021-1-15

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/717178-plotting-legends-in-loop-for-mean-and-standard-deviation-of-spectra#answer_598435

在 MATLAB Online 中打开

I think what you want to do is utilize the subset input for legend. What I usually do is something like this:

lns = [];
for i=1:M
    lns(i) = plot(wavenumbers1,(meanC(i,:));
    hold on;
    % plot other stuff
end
legend(lns,{"Label1", "Label2", "LabelM"});

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ardeshir moinian 2021-1-15

在 MATLAB Online 中打开

That is great! It worked as follows.

I want to show the legend for standard deviation as well (just once since it's the same color for all spectra). I did this:

for i=1:M;
    lns(i)=plot(wavenumbers1,(meanC(i,:)+i*30000));legend(legends(i));hold on
    hold on
    ptc(i)=patch([wavenumbers1' fliplr(wavenumbers1')], [((meanC(i,:)+i*30000)+stdC(i,:)) fliplr((meanC(i,:)+i*30000)-stdC(i,:))], 'r', 'FaceAlpha',0.5, 'EdgeColor','none')
   
end
legend(lns,legends);
legend(ptc,{'Standard Deviation'})

but I get this:

I guess the 2nd legend overrides the first one for "lns" but I want to keep both and I don't know how.

Thank you in advance!

Matt Gaidica 2021-1-15

在 MATLAB Online 中打开

Do this:

for i=1:M;
    lns(i)=plot(wavenumbers1,(meanC(i,:)+i*30000));
    hold on
    lns(M+1)=patch([wavenumbers1' fliplr(wavenumbers1')], [((meanC(i,:)+i*30000)+stdC(i,:)) fliplr((meanC(i,:)+i*30000)-stdC(i,:))], 'r', 'FaceAlpha',0.5, 'EdgeColor','none')
   
end
legend(lns,{legends{:},'Standard Deviation'});