Create multiple x axis for pcolor plot

I tried the method with http://au.mathworks.com/help/matlab/creating_plots/graph-with-multiple-x-axes-and-y-axes.html. However, it does not work for pcolor plot, as one of my x axis is the inverse of the other. I also have tried to used hold on and hold off, that went no where as well.

Answer 1

[Walter Roberson]

Perhaps File Exchange and set one of the axes handles to have 'Xdir', 'reverse' ?

[Sam Lo]

Inverse as the other x-axis is 1/(original x-axis) times some scalar. I am not sure if only by reverse will do the trick.

[Walter Roberson]

Sounds like the old frequency vs wavelength conversion. That should not be a problem.

For example,

c = 50;
x = sort(rand(1,75));
y = sin(x);
plot(x,y)
ax1 = gca;
minx = min(x);
maxx = max(x);
set(ax1,'xlim',[minx maxx])
ax1ylim = get(ax1, 'ylim');
ax2 = axes('Position', get(ax1,'Position'), 'xaxislocation', 'top', 'color', 'none');
set(ax2, 'xlim', [c./maxx c./minx], 'xdir', 'reverse', 'ytick', [], 'ylim', ax1ylim)
uistack(ax2, 'bottom')

Sending the second axis to the bottom is to prevent interference with any datatips.

The above code does not link the axes together for zooming or panning, and makes no attempt to create a combined datatip that shows both version of the x axis.