yyaxis plot is not working properly

Hi,

I have this double axis plot. the right side plot consists of 14 plots itself and I want it to be shown with different colors (like the second plot below), but I get them all with the same weird brown color.

Left side plot:

right side plot:

combined:

and here's the code I'm using:

figure(9)
yyaxis left
for i=1:size(w_SSI_r,2)
    y_mode{i} = ones(size(w_SSI_r{i},1),1)*(i+n_o_min-1);
    xlim([0 35])%%%%%%%%%%
    ylim([n_o_min n_o_max])
    scatter(w_SSI_r{i}/(2*pi),y_mode{i},'MarkerFaceColor','r','MarkerEdgeColor','k')
    hold on
    grid on
    y_mode_st0{i} = ones(size(w_SSI_r_st{i},1),1)*(i+n_o_min-1);
    scatter(w_SSI_r_st{i}/(2*pi),y_mode_st0{i},'MarkerFaceColor','g','MarkerEdgeColor','k')
    hold on
    grid on
end
%legend('Unstable Poles in Frequency','Stable Poles in Frequency')
ylabel('Model Order');
xlabel('Frequency (Hz)');
%title('Stabilization Diagram');


yyaxis right
for i=1:NDOF
    plot(f_FDD,pow2db(SV_FDD{i}),'DisplayName',['SV ',num2str(i)]);
    xlabel('Frequency (Hz)');
    ylabel('Singular Value (Power Spectral Density)(dB)');
    title('Singular Values of the SD Matrix')
    %xlim([0 round(max(Peaks_FDD_x))+1])
    %legend
    hold on
    grid on
end
ax = gca;
ax.YAxis(1).Color = 'k';
ax.YAxis(2).Color = 'k';

Answer 1

[Cris LaPierre]

See the Algorithms section of the yyaxis documentation page for an explanation of what is happening. Basically, yyaxis left will plot everything using the first color in the color order. You don't see that because you specify the color for those objects.

yyaxis right, then, uses the second color in the color order for all objects plotted on it.

yyaxis left
xlim([0 35])
ylim([15 60])
scatter(randi([0 35],[1 50]),randi([15 60],[1 50]))
hold on
scatter(randi([0 35],[1 50]),randi([15 60],[1 50]))
hold off
grid on

ylabel('Model Order');
xlabel('Frequency (Hz)');

yyaxis right
plot(randi([-90 -60],[35,4]));
ylim([-90 -10])
ylabel('Singular Value (Power Spectral Density)(dB)');
title('Singular Values of the SD Matrix')

The fix is to reset the colororder to default.

figure
yyaxis left
xlim([0 35])
ylim([15 60])
scatter(randi([0 35],[1 100]),randi([15 60],[1 100]),'MarkerFaceColor','r','MarkerEdgeColor','k')
hold on
scatter(randi([0 35],[1 100]),randi([15 60],[1 100]),'MarkerFaceColor','g','MarkerEdgeColor','k')
hold off
grid on

ylabel('Model Order');
xlabel('Frequency (Hz)');

yyaxis right
% reset the colorder
colororder('default')
plot(randi([-90 -60],[35,4]));
ylim([-90 -10])
ylabel('Singular Value (Power Spectral Density)(dB)');
title('Singular Values of the SD Matrix')

The fix is to reset the colororder before plotting into yyaxis right.

[Amir Hosein Shokouhy]

Hi Cris,

Thanks for your answer. The color is fixed now, how can I change the line styles? I want them all to be solid, not dashes.

Thanks,

Amir

[Cris LaPierre]

Set the linestyle in your plot command.

plot(randi([-90 -60],[35,4]),'LineStyle',"-");

If your linestyle is changing, that means MATLAB has already gone through all colors in the color order (there are 7 by default). Overriding this means you will have different data series that will look exactly the same (same color, marker and linestyle).

[Amir Hosein Shokouhy]

Perfect, thank you very much!