# How to plot and label a secondary x-axis in log?

4 views (last 30 days)
Sammy on 9 Jul 2021
Commented: Sammy on 15 Jul 2021
I tried to make a secondary x-axis but instead of 10^-3 to 10^1 like the primary x-axis (frequency), I wanted it to be 10^3 to 10^-1 since it should be in days. I tried plotting it using plotxx but I have difficulty getting log values. It should look like this.
figure
ax1=axes;
loglog(freq*24,PSDm,-1./freq/24,NaN*freq)
axis tight
ylim([1e1 1e11])
hold on
ax2=axes;
set(ax2,'Color','none')
set(ax2,'Ytick',[])
set(ax2,'XAxisLocation','top')
% xt = get(ax1,'XTick');
% set(ax2,'XTickLabel',xt)
xlabel(ax1,'frequency [cpd]')
xlabel(ax2,'period [days]')
ylabel(ax1,'kinetic energy density [m^2.s^{-2}/cpd]')
title('JOLO Residual Tides')
##### 0 CommentsShowHide -1 older comments

Sign in to comment.

### Answers (1)

Sam on 9 Jul 2021
Edited: Sam on 9 Jul 2021
A better way to go about this would be to have two different plots, and in one of them move the x - axis location to the top and do not label the y-axis. Refer to this official documentation provided by Mathworks for the same here
##### 1 CommentShowHide None
Sammy on 15 Jul 2021
Thanks! The plot above is made using plotxx( ) but without the log function. So you have to log the variables first. But thank you still, Sam. (:

Sign in to comment.

R2021a

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by