Adding a secondary x axis on the top of a line plot

In the line plot obtained after running the code appended below, xticks are to be added at the top such that their value is 50 times the xticks at the bottom of the plot. Moreover, an xlabel needs to be at the top also. Could someone help me with the code.

I had tried to implement some suggestions in previous posts on the topic, but somehow I get misaligned and overlapping axes. Thanks in advance.

x = 15:15:1800;
y1 = x./(1-x);
y2 = exp(-x./(1+x));
figure;
tiledlayout(1,1);
nexttile;
yyaxis left; plot(x/360,y1,'-bo'); hold on;
ylabel('PCC'); xlabel('time (days)');
yyaxis right; plot(x/360,y2,'-xr'); % hold on;
ylabel('DPCC (mm)'); % xlabel('time (days)');
axis square;
legend('PCC','DPCC','Location','East');

Answer 1

[Prachi Kulkarni]

Hi,

Following is a modified version of your code which will give you the secondary X axis at the top of the plot with an xlabel as required.

x1 = 15:15:1800;
y1 = x1./(1-x1);
y2 = exp(-x1./(1+x1));
x2 = 50*x1;
t = tiledlayout(1,1);

ax1 = axes(t);
l1 = plot(ax1,x1,y1,'-bo');
ax1.Color = 'none';
xlabel('time (days)'); ylabel('PCC');
axis square

ax2 = axes(t);
l2 = plot(ax2,x2,y2,'-xr');
ax2.XAxisLocation = 'top';
ax2.YAxisLocation = 'right';
ax2.Color = 'none';
xlabel('Label for top X axis'); ylabel('DPCC (mm)');
axis square

legend([l1;l2],'PCC','DPCC','Location','East');
ax1.Box = 'off';
ax2.Box = 'off';

For more information, please refer to the following documentation on adding multiple X and Y axes to your plots.

Display Data with Multiple Scales and Axes Limits

[SKP]

Thank you so much. This is precisely what I wanted.