How to change the Xtick direction of ONLY one of the two (top or bottom) X-axis lines ?

The following example shows two thick X-axis lines, one at the bottom and one at the top.

I would like to set the "TickDirection" as "Out" for the bottom X-axis line, and still keep the "TickDirection" as "In" for the top X-axis line.

How to do it?

% my plot
figure
plot(1:9)

% properties
ax = gca;
xax = ax.XAxis;
set(xax,'TickDirection','out')
set(xax,'TickLength',[0.03, 0.01])
set(xax,'Fontsize',20,'FontWeight','Bold','LineWidth',2);

Answer 1

[dpb]

% my plot
figure
plot(1:9)

% properties
hAx1 = gca;
hAx1.XAxis.TickDirection='out';
hold on
hAx2=axes('Position',hAx1.Position,'Color','none');
hAx2.XAxisLocation='top';
hAx2.YAxis.Visible='off';
hAx2.XAxis.TickDirection='in';

And you see you still have the ticks on the opposite side of each the X- and Y- axes. HG2 (Handle Graphics 2) doesn't have the granularity to control the tick marks individually; either they show if 'Box' is 'on' or they don't if 'off'.

You would have to draw either ticks or the outer box manually to create the effect you're after, unfortunately.

[Sim]

Thanks @dpb! However, from your text just after the plot, I did not understand what commands I should use to reproduce the effect I would like to see. Would it be possible to show with a code, or to elaborate a bit more what you wrote ? :-)

[dpb]

Well, I've not achieved precisely that effect myself, so I'm not so sure...but, let's try

% my plot
figure
plot(1:9)

% properties
hAx(1) = gca;
hAx(1).XAxis.TickDirection='out';
hAx(1).Box='off';
xline(max(hAx(1).XLim))
hold on
hAx(2)=axes('Position',hAx(1).Position,'Color','none');
hAx(2).XAxisLocation='top';
hAx(2).YAxis.Visible='off';
hAx(2).XAxis.TickDirection='in';
linkaxes(hAx)
hAx(2).XTickLabels=[];

That seems to replicate the desired case; it's unfortunate that the designers of HG2 didn't think of the problems created in having only one object handle for the box and that the tick marks for multiple axes are always competing with each other when using the box...the issue shows up any time one can't make the number of ticks the same on each axis which isn't always convenient for nice scaling.

Good luck, you'll undoubtedly run into issues with the above, but you should plan on plotting only into hAx(1) I think although I've not done any more testing.

[Sim]

thanks a lot!! that's a very nice solution :-)

I was reading the HG2 mechanism, but it looks a bit complicated (at least for me)... Many thanks again!

[dpb]

The bowels are deeply complicated, indeed...those articles are quite old by now, of course, and most of the glitches have been resolved and TMW has continued to improve performance since the initial release.

The more frustrating part (to me, at least) is the trend towards releasing special-purpose <"Standalone Visualizations"> and making more of the properties in other base function plots hidden so that it takes a lot of "handle-diving" to find the necessary pieces-parts to be able to make oftentimes quite normal customizations of the base figure appearance.

I see no justification for doing this; while it can be nice to have the easy-to-use version that makes all these assumptions about what the user wants, and those may be adequate for the majority of the need, as a general-purpose programming language and research tool, making it difficult to customize these for a particular purpose simply puts roadblocks in the way of the serious user and wastes their time doing trivial customizations instead of real research/productive work.

[Sim]

I agree 100% about everything you wrote!! And it is exactly what I think for years... often, to adjust the most trivial things in a plot - those things that one expects to be very easy to handle -, I spend a considerable time and they are not easily accessible. This means that we need to dig deep in obscure half-hidden and undocumented/uncommented properties... Sometimes I wonder if Matlab competitors, such as Python or R, have similar intricate properties and features related to graphical adjustments... :-)

Answer 2

[Sim]

This is just a variation of the @dpb solution, that I have used in one case.

Please note that I write it here - instead of adding it in a comment - as an alternative solution.

Obviously, I will not accept it since it is a rearrangement of the @dpb solution.

% my plot
figure
plot(1:9)

% define the first axes (from the current axes) and set some properties
ax(1) = gca;
set(ax(1),'Fontsize',15,'FontWeight','Bold','LineWidth',2, 'box','on');

% define the second axes  and set some properties
ax(2) = axes('Position',ax(1).Position,'Color','none');
ax(2).XAxisLocation = 'bottom';
ax(2).YAxis.Visible = 'off';
ax(2).XAxis.TickDirection = 'out';
ax(2).XTickLabels = [];
ax(2).XTick = [0 ax(1).XTick];        % <-- Xticks positions in the 2nd axes as in the 1st axes

% link the first axes with the second axes
linkaxes(ax)

% other properties
ax(1).XRuler.TickLabelGapOffset = 20; % <-- adjust ticklabels away from axes
ax(2).XAxis.TickLength=[0.05 0];      % <-- change the length of the tick marks
set(ax(2),'Fontsize',15,'FontWeight','Bold','LineWidth',2, 'box','off');