Change format of field contour labels that have been manually added in a tiled layout

Hi,

Trying to manually add contour labels over a filled contour plot over a narrow range of values.

Matlab returns the error:

Error using hgconvertunits

The reference object is invalid.

Any ideas how I can manually add labels to a tiledlayout?

I also assume there is no workaround for avoiding the contours from striking through the labels when added manually?

Thank you

a = 0.98;
b = 1.02;
Z = round(((b-a).*rand(99,99) + a),2);
XY = [-0.375:.125:.375];
no_levels = 8;
npoints = [99 99]; % define improved resolution
Xfine = linspace(XY(1),XY(end),npoints(1)); % y coords
Yfine = linspace(XY(1),XY(end),npoints(2)); % z coords
[Xfine Yfine] = meshgrid(Xfine,Yfine); % create mesh

tiledlayout(1,2)

for i = 1:2
    nexttile(1)

    [C,H] = contourf(Xfine,Yfine,Z,no_levels,'-');
    % clabel(C,H,'interpreter','latex','FontSize',14);
    % H.LevelList = round(H.LevelList,1);  % rounds levels to 1st decimal place
    clabel(C,H,"manual",'FontSize', 22)
    
    hold on
    ylim([-0.5 0.5]);
    y = ylim;
    yticks([y(1):.25:y(2)])
    xticks([-.5:.25:.5])
    xlim([-.55 .55])
    axis square
end

Answer 1

[Mathieu NOE]

why not create explicitely the levels (V array) ?

a = 0.98;
b = 1.02;
Z = peaks(99)/100 + (a+b)/2 ;

XY = [-0.375:.125:.375];

no_levels = 8;
V = round(linspace(min(Z,[],'all'),max(Z,[],'all'),no_levels),2); % create levels explicitely

npoints = [99 99]; % define improved resolution
Xfine = linspace(XY(1),XY(end),npoints(1)); % y coords
Yfine = linspace(XY(1),XY(end),npoints(2)); % z coords
[Xfine, Yfine] = meshgrid(Xfine,Yfine); % create mesh
tiledlayout(1,2)
for i = 1:2
    nexttile(1)
    [C,H] = contourf(Xfine,Yfine,Z,V);
    clabel(C,H,'interpreter','latex','FontSize',10);
    
    hold on
    ylim([-0.5 0.5]);
    y = ylim;
    yticks([y(1):.25:y(2)])
    xticks([-.5:.25:.5])
    xlim([-.55 .55])
    axis square
end

[Daniel]

Yes, this seems like a reasonable solution. These things are really not satisfying to work with! Thank you

Answer 2

[praguna manvi]

Hi @Daniel,

I also observed the same error at “clabel(C, H, “manual”)” inside tiledLayout. I find that you could use subplot for manual labelling as follows to achieve the same effect for a 1 x 2 layout:

a = 0.98;
b = 1.02;
Z = round(((b-a).*rand(99,99) + a),2);
XY = [-0.375:.125:.375];
no_levels = 8;
npoints = [99 99]; 
Xfine = linspace(XY(1),XY(end),npoints(1)); 
Yfine = linspace(XY(1),XY(end),npoints(2));
[Xfine, Yfine] = meshgrid(Xfine,Yfine);

figure;

for i = 1:2
    subplot(1, 2, i); 

    [C,H] = contourf(Xfine,Yfine,Z,no_levels,'-');
    clabel(C,H,"manual",'FontSize', 22, "Color", [1, 1, 1]);
    hold on;
    ylim([-0.5 0.5]);
    y = ylim;
    yticks([y(1):.25:y(2)]);
    xticks([-.5:.25:.5]);
    xlim([-.55 .55]);
    axis square;
end

Hope this helps!

[Daniel]

Thank you for your help, Praguna. So many of my plots are in tiled layouts, I actually don't think that it's worth the effort to change everything for a few labels. I'm never content with how they look anyway, manually placed or otherwise. I'll just stick with the colour axis to guide the reader.