How to change the colorbar limits in a previously saved fig file

Hello,

I have a figure containing a colorbar that I saved in a .fig format.

Now I need to open it and change the limits of the color bar. Im using

caxis([inferior_limit superior_limit])

.

However, when I do this nothing happens.

What Im doing wrong?

Thank you

Answer 1

[Walter Roberson]

figfilename = 'AppropriateFile.fig';
fig = openfig(figfilename);
cb = findobj(fig, 'type', 'Colorbar');
cb.Limits = [inferior_limit superior_limit];

After that you might want to save the figure indicates in fig into a new file.

[Ricardo Duarte]

Hello Walter,

The code you provided allow me to change the colorbar limits however it doesn't change the colorgradient in my figure.

Please, have a look on my code

SPLfigure=figure; %Just for normal window size
%figure('units','normalized','outerposition',[0 0 1 1]); %FOR A MAXIMIZED WINDOW
ax1=axes;
imagesc(ax1,km2deg(Xv),km2deg(Yv),SPL_dB);
set(gca,'YDir','normal');
h=colorbar(ax1,'southoutside');
ylabel(h,'Sound Pressure Level (dB)');
clear title
title({['SPL Broadband'], ['Source at: [', num2str(km2deg(Sx)),';',num2str(km2deg(Sy)),'] ','/ Receiver layer at:', num2str(rd(rdindex)),'m deep']});
xlabel('LONGITUDE');
ylabel('LATITUDE');
axis tight;
clear title
ax2=axes;
contourf(ax2,km2deg(lon_km),km2deg(lat_km),elevation', [-rd(rdindex) -rd(rdindex)],'w','facecolor','w');
ax3=axes;
contourf(ax3,km2deg(lon_km),km2deg(lat_km),elevation', [0 0],'facecolor',[0.5 0.5 0.5]);
linkaxes([ax1,ax2,ax3]);
ax2.Visible = 'off';
    ax2.XTick = [];
    ax2.YTick = [];
ax3.Visible = 'off';
    ax3.XTick = [];
    ax3.YTick = [];    
set([ax1,ax2,ax3],'Position',[.17 .11 .685 .815]);
ax2.Visible = 'on';
ax2.Visible = 'off';
ax3.Visible = 'on';
ax3.Visible = 'off';

axes(ax1); axis equal;
axes(ax2); axis equal;
axes(ax3); axis equal;
hold on;

portugal=text((-8.6),(38.3),'Portugal','FontSize',20); 
set(portugal,'Rotation',90);

setubal=text((-9.0),(38.55),'Setubal','FontSize',14);
caxis(ax1,[0 200]);
ax1.XGrid         = 'on';
ax1.YGrid         = 'on';
ax1.GridColor = [1, 1, 1];  % [R, G, B]

hold on; contourf(km2deg(lon_km),km2deg(lat_km),elevation', [-50 -50],'w','ShowText','on','facecolor','none'); %linha dos 50m 
hold on; contourf(km2deg(lon_km),km2deg(lat_km),elevation', [-100 -100],'w','ShowText','on','facecolor','none'); %linha dos 100m
hold on; contourf(km2deg(lon_km),km2deg(lat_km),elevation', [-250 -250],'w','ShowText','on','facecolor','none'); %linha dos 250m 
%hold on; contourf(km2deg(lon_km),km2deg(lat_km),elevation', [-500 -500],'w','ShowText','on','facecolor','none'); %linha dos 500m 
hold on; contourf(km2deg(lon_km),km2deg(lat_km),elevation', [-1000 -1000],'w','ShowText','on','facecolor','none'); %linha dos 1000m 
hold on; plot(km2deg(Sx),km2deg(Sy),'.k');

Thank you in advance,

[Walter Roberson]

Your colorbar is associated with your imagesc(), and you do not appear to be passing a scale range into the imagesc() call. imagesc() with no scale range maps min() of the data to the first color and maps max() of the data to the last color. Changing the colorbar range is not going to affect that.

Possibly:

figfilename = 'AppropriateFile.fig';
fig = openfig(figfilename);
cb = findobj(fig, 'type', 'Colorbar');
ax = cb.Axes;   %hidden property
caxis(ax, [inferior_limit superior_limit]);

[Ricardo Duarte]

I don't understand the problem saving my figure.

Im saving the figure like this:

savefig(h,'teste.fig')

However I get the following error:

H must be an array of handles to valid figures.

Why this happen? How to correct it?

Thank you.

[Walter Roberson]

What is h in this case?

The only h you have shown so far was

h=colorbar(ax1,'southoutside');

but colorbars are not figures.

And by the time you are loading back in a previously saved figure using the code I showed such as https://www.mathworks.com/matlabcentral/answers/1561631-how-to-change-the-colorbar-limits-in-a-previously-saved-fig-file#comment_1780981 then h is long gone . With that code, to re-save you would

savefig(fig, 'teste.fig')

[Ricardo Duarte]

In your previous comment https://www.mathworks.com/matlabcentral/answers/1561631-how-to-change-the-colorbar-limits-in-a-previously-saved-fig-file#comment_1780981 , you mentioned that the colorbar is associated with imagesc but it is not passing a scale range into the imagesc() call.

Is there a way to do it? The idea is to avoid to open a saved fig and re-save it again.

Thank you.

[Walter Roberson]

imagesc() sets the image 'CDataMapping', 'scaled' . If a non-empty scale range is provided, then it also sets the axes CLim property to that range; if "hold" was off then it also sets the axes CLimMode to 'auto'

This is almost the same calling imagesc() without a range and then calling caxis() yourself; the difference is just in whether CLimMode is set to 'auto' or not (caxis does not set it.)

If you still have your figure up but you want to change the caxis and save again while it is still up, then referring to your previous code,

caxis(ax1, [inferior_limit superior_limit]);

savefig(SPLfigure, 'teste.fig')

[Ricardo Duarte]

Thank you Walter!