MATLAB fail to create Chart with Multiple x-Axes and y-Axes

Dear all, the objective was to two x-Axes and y-Axes. However, I am unable to produce the intended graph even follow the MATLAB Example. The 2 signals does not overlap into each other, instead one of the signal cover entirely the first signal that being plot.

I really appreciate if someone can point what I have been missing. Thanks in advance

The following code has been used but without success.

load('st_data.mat');
figure
errorbar(st_X_hour, st_Vec_Y1_mean, st_Vec_Y1_Sd, '--x','MarkerSize',15)
ax1 = gca; % current axes
set(ax1, 'Xtick', st_Xaxis_intrmit, 'XTickLabel',st_XLabel,'XAxisLocation','top'); xtickangle(90)
ax1_pos = ax1.Position; % position of first axes
ax2 = axes('Position',ax1_pos,'XAxisLocation','top','YAxisLocation','right', 'Color','none');
plot(st_X_hour,st_Y2,'Parent',ax2,'Color','k')

Answer 1

[Walter Roberson]

When ax2 is created, by default its NextPlot property is set to 'replace'. When the next graphics operation is done (the plot call), the graphics system sees that replace is in effect, and does a cla(), which leaves position the same but happens to reset the Color property back to the default [1 1 1].

You can deal with this by,

ax2 = axes('Position', ax1_pos, 'XAxisLocation', 'top', 'YAxisLocation', 'right', 'Color', 'none', 'NextPlot', 'add');

or you can deal with it by

 hold(ax2, 'on')

before doing the plot().

But do not just deal with it by

set(ax2, 'Color', 'none')

after doing the plot(), as the cla that was done on your behalf also reset the axis locations.

[balandong]

Hi Walter,

Thanks for the quick response, I really appreciate it. Even though you suggestion does solve the overlapping problem, but other problem arise. For example, the two signal does not aligned relative to the same time frame. In addition, there are unwanted thick at both the bottom of X-axis and Right of Y-axis.May I know, how to handle this?

Following is the code to produce the above graph.

load('st_data.mat');
figure
errorbar(st_X_hour, st_Vec_Y1_mean, st_Vec_Y1_Sd, '--x','MarkerSize',15)
ax1 = gca; % current axes
set(ax1, 'Xtick', st_Xaxis_intrmit, 'XTickLabel',st_XLabel,'XAxisLocation','top'); xtickangle(90)
ax1_pos = ax1.Position; % position of first axes
ax2 = axes('Position',ax1_pos,'XAxisLocation','bottom','YAxisLocation','right', 'Color','none', 'NextPlot', 'add');
plot(st_X_hour,st_Y2,'Parent',ax2,'Color','k')

[Walter Roberson]

I think it would be easier if you used plotyy

ax = plotyy(st_X_hour, st_Vec_Y1_mean, st_X_hour, st_Y2, @(x,y) errorbar(x, y, st_Vec_Y1_Sd, '--x', 'MarkerSize', 15), @(x,y) plot(x, y, 'k') );
set(ax(1), 'Xtick', st_Xaxis_intrmit, 'XTickLabel',st_XLabel);
xtickangle(ax(1), 90);

[balandong]

Hi Walter, Thank you for the really excellent suggestion, never knew about the existence of PLOTYY. I thought only YYAXIS right & left have such capability.

I know this question beyond the original scope of this thread, but im tempted to know how can access the second Axes? I tried ax(2), but nothing is changing! FYI, I want to change the label at the bottom X-axis into number, such that

ax = plotyy(st_X_hour, st_Vec_Y1_mean, st_X_hour, st_Y2, @(x,y) errorbar(x, y, st_Vec_Y1_Sd, '--x', 'MarkerSize', 15), @(x,y) plot(x, y, 'k') );
set(ax(1), 'Xtick', st_Xaxis_intrmit, 'XTickLabel',st_XLabel,'XAxisLocation','top');
xtickangle(ax(1), 90);
ylim(ax(1),[0.5 5.5])
nox=273:20:400;
set(ax(2), 'Xtick', nox, 'XTickLabel',1:numel(nox),'XAxisLocation','bottom');

However, running the above code changing nothing!.

Similarly, I want to change the interval of thicklabel at the second Y-axis. I think the syntax should be the same.

Thanks in advance.

ps- I still wonder how you able to entertain so many MATLAB related queries in a day. I am still amazed from your matlab activity log