Plotting two x axes with one Y-axis, and second x axis are non-ordered numbers

I am trying to plot mixing depth as a function of day of the year (first x-axis) and the corresponding latitude where measurements were taken for that date. The issue is that the labels of the second axis need to be added text, because they are not always in numerical order. I can get them to plot but they do not align correctly or do not include all the labels for the second x-axis. I use Matlab R2015a.

This is an example of latitudes correspond for each day of year.

N2_Stn_doy = 138 139 140 141 142 143 143 145 146 147 148 150 N2_Stn_Lat= 54.43 56.34 56.23 53.55 53.48 50.23 49.97 47.65 47.54 47.38 47.29 44.11

matrix1=[N2_Stn_doy;N2_Stn_MLD];

h=figure(6) line(matrix1(1,:), matrix1(2,:),'Color','b'); hold on axis([138,150, 0 300]); set(gca, 'YDir', 'reverse') xlabel('day of year'); ylabel ('Depth (m)');

ax1=gca; %ax2 = axes('Position',get(ax1,'Position'),'XAxisLocation','top','YAxisLocation','left',... % 'Color','none','XColor','k','YColor','k'); ax2 = axes('Position',get(ax1,'Position'),'XAxisLocation','top','YAxisLocation','right','Color','none','XColor','k','YColor','k');

k=get(ax1,'XTick'); l=get(ax1,'Position'); set(ax2,'YTick',([])); set(ax2,'Position',l,'Xlim',([44.11 54.43]),'XTickLabel',{'54.43' '56.34' '56.26' '53.54' '53.48' '50.23' '49.97'... '47.65' '47.54' '47.38' '47.29' '44.11'}); %set(ax2,'YTickLabel', num2str(get(ax2,'YTick'),'%.2f\n'),'FontName','Times New Roman','FontSize',24); c=get(ax2,'XLabel'); set(c,'String','Latitude (^{\circ}N)');

Answer 1

[Honglei Chen]

I would replace the code after

ax1 = gca;

with the following

ax2 = axes('Position',get(ax1,'Position'),'XAxisLocation','top','YAxisLocation','right','Color','none','XColor','k','YColor','k'); 

k=get(ax1,'XTick');
l=get(ax1,'Position');
line(matrix1(1,:), nan(1,size(matrix1,2)),'Parent',ax2); 

set(ax2,'YTick',([]));
set(ax2,'XTickLabel',{'54.43' '56.34' '56.26' '53.54' '53.48' '50.23' '49.97'...
    '47.65' '47.54' '47.38' '47.29' '44.11'});
%set(ax2,'YTickLabel', num2str(get(ax2,'YTick'),'%.2f\n'),'FontName','Times New Roman','FontSize',24);
c=get(ax2,'XLabel');
set(c,'String','Latitude (^{\circ}N)');

This is essentially your code with an invisible line and then set the axis label to what you have in your code. Is this what you want?

HTH

[Kristina Mojica]

Thank you for your answer. However

    % line(matrix1(1,:), nan(1,size(matrix1,2)),'Parent',ax2);

Did not lead to any changes in the figure.

[Honglei Chen]

What do you want to plot? I don't see that in your code either. What I did here is to make sure the x axis is properly populated so you can replace the tick label with what you want. You can technically plot anything here as long as you use the desired x values.

HTH

Answer 2

[bluestar67]

Matrix 1 is day of the year and depth [doy; depth]

matrix1 =

138.0000  139.0000  140.0000  141.0000  142.0000  143.0000  143.5000  145.0000  146.0000  147.0000  148.0000  150.0000
 14.0118   37.0378    5.5054   22.0171   22.5176   12.0057   16.5077  237.5580  155.2366    7.6018   12.4024   32.4972

This corresponds to the bottom x-axis and y-axis. I want to add a top x-axis with the Latitudes for each of the doy.

A matrix of [doy; Latitude]

Lat_doy =

138.0000  139.0000  140.0000  141.0000  142.0000  143.0000  143.5000  145.0000  146.0000  147.0000  148.0000  150.0000
 54.4295   56.3376   56.2644   53.5448   53.4816   50.2292   49.9726   47.6472   47.5413   47.3786   47.2932   44.1085