Plot both global and local legend

In the tiledlayout, I am trying to plot both global and local legend.

X = rand(5); 
Y = rand(5);

figure
tiledlayout(2,1);
nexttile
    plot(X(1,:),Y(1,:), 'r'); hold on;
    plot(X(2,:),Y(2,:), 'k');     hold on;
    plot(X(3,:),Y(3,:), 'k--');   hold on;
    legend('Reference', 'Location', 'NorthWest');
nexttile 
    plot(X(1,:),Y(1,:), 'r', 'HandleVisibility','off'); hold on;
    plot(X(4,:),Y(4,:), 'k');     hold on;
    plot(X(5,:),Y(5,:), 'k--');   hold on;
    % legend('Reference', 'Location', 'NorthWest');
My_LGD = legend('Signal 1', 'Signal 2');
My_LGD.Orientation = "horizontal";
My_LGD.NumColumns = 4;
My_LGD.Layout.Tile = "South";

This is the minimal working example I am using. I want to have a global legend showing Signal 1 and Signal 2 and then a local legend to highlight the e.g., Reference signal.

I had to hide the first plot in the second plot 'HandleVisibility','off' so my global legend takes the second two signals. Otherwise, is shows red line next to Signal 1 and black solid line next to Signal 2.

You can see in the second Figure, that local legend is in both plots (what I want), and in the first figure is what the code gives me.

[Mike Buba]

If I slightly modify the code; add ax=axes('Position',get(gca,'Position'),'Visible','Off'); and assigned p1, p2, etc. to the each plot. the plotting the last legend is done as: My_LGD = legend(ax, [p2 p3], {'Signal 1', 'Signal 2'});

X = rand(5); 
Y = rand(5);
figure
tiledlayout(2,1);
nexttile
    p1 = plot(X(1,:),Y(1,:), 'r'); hold on;
    p2 = plot(X(2,:),Y(2,:), 'k');     hold on;
    p3 = plot(X(3,:),Y(3,:), 'k--');   hold on;
    legend('Reference', 'Location', 'NorthWest');
nexttile 
    p1 = plot(X(1,:),Y(1,:), 'r'); hold on;
    p4 = plot(X(4,:),Y(4,:), 'k');     hold on;
    p6 = plot(X(5,:),Y(5,:), 'k--');   hold on;
    legend('Reference', 'Location', 'NorthWest');
ax=axes('Position',get(gca,'Position'),'Visible','Off');

My_LGD = legend(ax, [p2 p3], {'Signal 1', 'Signal 2'});
My_LGD.Orientation = "horizontal";
My_LGD.NumColumns = 4;
My_LGD.Layout.Tile = "South";

However, the My_LGD.Layout.Tile = "South"; gives an error:

Property assignment is not allowed when the object is empty.
Use subscripted assignment to create an array element.

Error in test (line 20)
My_LGD.Layout.Tile = "South";

It seems I can't get a global legend to appear outside the plot. Anyone knows what to do?

Answer 1

[Benjamin Kraus]

Your hidden axes (and global legend) needs to have the tiledlayout as a parent.

X = rand(5); 
Y = rand(5);
figure
tcl = tiledlayout(2,1); % I added an output argument from tiledlayout here.
nexttile
    p1 = plot(X(1,:),Y(1,:), 'r'); hold on;
    p2 = plot(X(2,:),Y(2,:), 'k');     hold on;
    p3 = plot(X(3,:),Y(3,:), 'k--');   hold on;
    legend('Reference', 'Location', 'NorthWest');
nexttile 
    p1 = plot(X(1,:),Y(1,:), 'r'); hold on;
    p4 = plot(X(4,:),Y(4,:), 'k');     hold on;
    p6 = plot(X(5,:),Y(5,:), 'k--');   hold on;
    legend('Reference', 'Location', 'NorthWest');
ax=axes(tcl,'Visible','Off'); % I modified this line to specify the parent and ignore position.
My_LGD = legend(ax, [p2 p3], {'Signal 1', 'Signal 2'});
My_LGD.Orientation = "horizontal";
My_LGD.NumColumns = 4;
My_LGD.Layout.Tile = "South";

[Mike Buba]

Thanky you @Benjamin Kraus!