How to add a legend for multiple figures with horizontal and south location

% Please how can add one legends for the subplots. I want the legend
% location to south and horizontal. I also want to break the legend into
% two lines.
% load
mydata = load('data.mat')

mydata = struct with fields:
         nt: 101
      paras: [1×1 struct]
          t: [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 … ] (1×101 double)
    thetazt: [101×201×2 double]
        vzt: [101×201×2 double]
     xivals: [-0.2000 0.2000]
          z: [0 1.0000e-06 2.0000e-06 3.0000e-06 4.0000e-06 5.0000e-06 6.0000e-06 7.0000e-06 8.0000e-06 9.0000e-06 1.0000e-05 1.1000e-05 1.2000e-05 1.3000e-05 1.4000e-05 … ] (1×201 double)
         zm: 101

xivals = mydata.xivals

xivals = 1×2

-0.2000 0.2000

pars = mydata.paras;

% u value
u = pars.u;


z = mydata.z;
t = mydata.t;
nt = mydata.nt;

% theta and v
thetazt = mydata.thetazt;
vzt = mydata.vzt;


%% Plot

fig1 = figure(1);
T = tiledlayout(2,2, 'TileSpacing', 'compact');
tinds=[2, 4, 6, 11, 16, 21, 26];                 
nit=length(tinds);
nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p1 = plot(z, thetazt(tinds(it), :, 1), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1);
end

nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p2 = plot(z, thetazt(tinds(it), :, 2), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p3 = plot(z, vzt(tinds(it), :, 1), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1 );
end
nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p4 = plot(z, vzt(tinds(it), :, 2), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1);

end
% Create a Legend with the data from multiple axes
lg = legend([p1,p2,p3,p4]);
lg.Location = 'south';
lg.Orientation='horizontal';

Answer 1

[Star Strider]

I am not certain what you want.

Try this —

% Please how can add one legends for the subplots. I want the legend
% location to south and horizontal. I also want to break the legend into
% two lines.
% load
mydata = load('data.mat')

mydata = struct with fields:
         nt: 101
      paras: [1x1 struct]
          t: [0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 ... ] (1x101 double)
    thetazt: [101x201x2 double]
        vzt: [101x201x2 double]
     xivals: [-0.2000 0.2000]
          z: [0 1.0000e-06 2.0000e-06 3.0000e-06 4.0000e-06 5.0000e-06 6.0000e-06 7.0000e-06 8.0000e-06 9.0000e-06 1.0000e-05 1.1000e-05 1.2000e-05 1.3000e-05 ... ] (1x201 double)
         zm: 101

xivals = mydata.xivals

xivals = 1x2

-0.2000 0.2000

pars = mydata.paras;

% u value
u = pars.u;


z = mydata.z;
t = mydata.t;
nt = mydata.nt;

% theta and v
thetazt = mydata.thetazt;
vzt = mydata.vzt;


%% Plot

fig1 = figure(1);
T = tiledlayout(4,2, 'TileSpacing', 'compact');             % Change To Specify 3 Rows
tinds=[2, 4, 6, 11, 16, 21, 26];                 
nit=length(tinds);
nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p1(it) = plot(z, thetazt(tinds(it), :, 1), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1);
end


nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p2(it) = plot(z, thetazt(tinds(it), :, 2), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p3(it) = plot(z, vzt(tinds(it), :, 1), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1 );
end
nexttile(T)
hold on
for it=1:length(tinds)
    xi_part = "\xi = " + xivals(1);
    t_part = ", t = " + t(tinds(it));
    dn1 = xi_part + t_part;
    p4(it) = plot(z, vzt(tinds(it), :, 2), 'Color',[1-(it-1)/(nit-1),(it-1)/(nit-1),1], 'DisplayName', dn1);

end
lt = nexttile(5,[2 2]);                                     % Use Row 3 For Legend Location
% get(lt)
% Create a Legend with the data from multiple axes
lg = legend([p1,p2,p3,p4]);
lg.Location = 'south';
lg.Orientation='vertical';
lg.Position = lt.Position;
lg.NumColumns = 2;
lt.Visible = 'off';

EDIT — (24 Feb 2024 at 17:25)

Subscripted ‘p1’ ... ‘p4’ so that they now all appear in the legend, as requested in the Comment.

.

[University]

Thank you for this but why is it that on the only the final values of t that appears in the legend, why not t=1, t= 3, ... t=25 for each xi=-0.2?

[Star Strider]

My pleasure!

You did not request that, so I did not consider it.

You need to subscript ‘p1’ through ‘p4’ to have all of them appear in the legend, otherwise only the last will be saved and appear because each iteration over-writes the previous result in that instance.

Subscripting them (as I edited the code to do) will save all of them and present all of them in the legend, as it does now.

I am not certain what you want in the legend, so I present all ‘p1’ through ‘p4’ in it, and expanded it with:

lt = nexttile(5,[2 2]); % Use Row 3 For Legend Location

so that the entries are readable (otherwise they are squashed together). If you want to display fewer entries, you can certainly do that by limiting the entries presented to it (right now I use all of them).

The previus value for the legend tile was:

lt = nexttile(5,[1 2]); % Use Row 3 For Legend Location

so use that in the event you want to go back to it with fewer legend entries.

.

[University]

Thank you for your explanation

[Star Strider]

As always, my pleasure!