addtxaxis

Adds a top x-axis with arbitrary scale

Description

This function adds a second dummy x-axis on the top of a given axes object. This dummy x-axis has (internally) the same scaling (linear or log) than the main x-axis, but is used to display ticks and tick labels which are on a transformed scale.

The transformation is arbitrary, but the transformed axis cannot be used to create plots with transformed x coordinates. The given transformation is in fact the inverse transform, that is, the transform used to go from the secondary axis to the original axis (e.g. displaying a log scale would be done by providing a transform '10.^x').

The transformed axis can be removed cleanly by issuing a simple command.

Typical uses of addtxaxis would include displaying a secondary x-axis following reciprocal or logarithmic scales (e.g. frequency and wavelength on the same plot).

• Acknowledgements: This submission has inspired the following:; Add top X-axis with different scale
• MATLAB release: MATLAB 6.5 (R13)

[Jakob van Bethlehem]

doesn't work for some reason

[Jakob van Bethlehem]

I have to change my previous entry. I did work very nice. I didn't really understand the error message I got in the beginning but when this changed I got the script working. So what was the problem. I got a variable c defined in my workspace. I wanted a transformation 'log10(c)-x', but the script didn't recognize this c. In my case c was a single constant so I could just calculate the value of log10(c) and put that in the string. That worked, but this might give problems for others if c is an array instead of a number. I don't really understand why the c was not recognized. I mean: the Matlab functions don't give problems. This does need improvement however.

[François Bouffard]

A fix was submitted on 2003-10-22 so that the expression of the transform is now evaluated in the base workspace, thus enabling the use of variables defined there.

[François Bouffard]

Sorry for any inconvenience; the fix was not correctly submitted on 2003-10-22, and was resubmitted on 2004-06-09. The current version now really fixes J. van Bethlehem's problem.

[kris zacny]

Program works very well. I also received a lot of help from François explaining how the program works and how to plot my specific data sets. He did a real good job explaining and trying to understand my needs. Thank you so much!

Kris

[John Lipp]

Great little chunk of code. Adding a second x axis is not easy, but this makes it a far more manageable task!
Would score 5 in my opinion if it could auto determine the ticks...

[Markus Loecher]

Very nice utility. I wished for two things:
 - an option to have the tick and axis labels (of the new top axis) face inward and maybe even place the axis label to the right instead of center (so they won't interfere with the title)
- a simple example of usage.

[Carlos Baiz]

This is what I was looking for. Thanks.

[Tom Allison]

Thank you so much. Saved me hours.

[Saeed Tahvili]

Very Good, thanks...
I was looking for that as well.
A simple example would be really helpful.

[Amol Singh]

This was a really nice program. I was autoamting a plotting process and wanted reciprocal axis at the top of x axis. Although i modified program to write a multiplied value ie instead of 0.2 i wanted it to be 200.
good work indeed...

[Hai Dinh]

Dear François Bouffard:

Are there any way to add the top x-axis that is has a one-to-one relationship to the bottom main x-axis? (not linear nor log scale as explained in your program)

Thanks,
Hai Dinh

[François Bouffard]

In reply to Hai Dinh: using addtxaxis, you can simply provide 'x' as the transform. However the ticks argument is also mandatory, so that you will have to provide a vector of tick positions as well. Maybe using plotxx by Denis Gilbert (also available on MatlabCentral's FileExchange) would be easier for you.

[AHMET ANIL DINDAR]

Thanks, what I was looking for.

[Natalia Gomez]

Exactly what I needed!

[Stephen]

I love the idea of this program but François can you please give an example of usage because it is not really clear what you mean by providing a vector of ticks. Can it just be the ticks I want to show up on that axis? (ie v=[1 2 3 4] ?)