MATLAB: Dynamic Legends plot option (error: two legend lines for each plot)

dynamic legendplot

I have a function which makes a plot from different vectors, then each time that I add a new plot I need to add a new legend which is a variable(legend) now I trying to do it with the next code:

plot_test = plot(vector1, vector2, '-mo','Color',color, 'DisplayName',legend);
hold all;
legend('-DynamicLegend');

but as result I got two new legends for each plot, one whith the real name and another called line2, line4, line6….and so on depending the number of plots…

Any help please?

Best Answer

Look at this example

x=0:0.1:10;
y1=sin(x);
plot(x,y1)
hl=legend('leg1')
hold all
y2=cos(x)
plot(x,y2)
leg=[get(hl,'string'), 'leg2']
hl=legend(leg)

Related Solutions

MATLAB: Legend for yyaxis at two different locations

The second call to legend() is replacing the first legend (you can only have 1 legend).

I reworked your code to use yyaxis instead of plotyy.

Solution 1: use 1 legend

This solution puts all handles into the same legend. See inline comments for details.

n=-180:180;
x=(pi/180).*n;
y=sin(x);
y2=sin(x).*cos(x);
y3=cos(x);
% Plot on left axis

yyaxis left
h1 = plot(n,y, '-k', 'LineWidth', 1, 'DisplayName', 'h1'); 
set(gca, 'YColor', 'k') % set y axis color to same as line color



hold on
h3=line(n,y3,'Color','r','LineWidth',2, 'DisplayName', 'h3');
% Plot on right axis

yyaxis right
h2 = plot(n,y2, '-b', 'LineWidth', 1.5, 'DisplayName', 'h2'); 
set(gca, 'YColor', 'b') % set y axis color to same as line color

Solution 2: kludge in a 2nd legend

Since you can only have 1 legend per axis, this solution produces a second invisible axis and copies the h2 object to the invisible axis so that it can have its own legend. See inline comments for details.

n=-180:180;
x=(pi/180).*n;
y=sin(x);
y2=sin(x).*cos(x);
y3=cos(x);
% Plot on left axis
yyaxis left
h1 = plot(n,y, '-k', 'LineWidth', 1, 'DisplayName', 'h1'); 
set(gca, 'YColor', 'k') % set y axis color to same as line color
hold on
h3=line(n,y3,'Color','r','LineWidth',2, 'DisplayName', 'h3');
% Plot on right axis
yyaxis right
h2 = plot(n,y2, '-b', 'LineWidth', 1.5, 'DisplayName', 'h2'); 
set(gca, 'YColor', 'b') % set y axis color to same as line color
% Produce left-axis legend
legend([h1,h3], 'Location', 'NorthWest')
% Create invisible axis in the same position as the current axes
ax = gca(); % Handle to the main axes
axisCopy = axes('Position', ax.Position, 'Visible', 'off');
% Copy objects to second axes
hCopy = copyobj(h2, axisCopy); 
% Replace all x values with NaN so the line doesn't appear
hCopy.XData = nan(size(hCopy.XData)); 
% Create right axis legend
legend(hCopy, 'Location', 'NorthEast')

MATLAB: How do i change the linewidth and the fontsize in a legend

Solved!!!

[~, hobj, ~, ~] = legend({'ONE','TWO'},'Fontsize',12,'Location','Northeast');
hl = findobj(hobj,'type','line');
set(hl,'LineWidth',1.5);
ht = findobj(hobj,'type','text')
set(ht,'FontSize',12);

Best Answer

Related Solutions

MATLAB: Legend for yyaxis at two different locations

MATLAB: How do i change the linewidth and the fontsize in a legend

Related Question