overlaying graph contourf (or pcolor)

I wrote some code that represents this figure:

The code is this:

%% errori relativi

% tau1

figure(2)

sgtitle('ERRORI RELATIVI ')

subplot(1,3,1)

pcolor(a1/l1, y/l1, delta_tau1./abs(tau1)*100);

contourf(a1/l1, y/l1, delta_tau1./abs(tau1)*100)

title('$\Delta \tau_{\%} \ [\%]$');

colorbar('southoutside')

xlabel('$\frac{x}{l}$')

ylabel('$\frac{y}{l}$')

axis equal

xlim([min(min(a1/l1)), max(max(a1/l1))]);

ylim([min(min(y/l1)), max(max(y/l1))]);

grid on

% Q1

subplot(1,3,2)

pcolor(a1/l1, y/l1, delta_Q./abs(Q)*100);

contourf(a1/l1, y/l1, delta_Q./abs(Q)*100)

title('$\Delta Q_{\%} \ [\%]$');

colorbar('southoutside')

xlabel('$\frac{x}{l}$')

ylabel('$\frac{y}{l}$')

axis equal

xlim([min(min(a1/l1)), max(max(a1/l1))]);

ylim([min(min(y/l1)), max(max(y/l1))]);

grid on

% Ek1

subplot(1,3,3)

pcolor(a1/l1, y/l1, delta_Ek./abs(Ek)*100);

contourf(a1/l1, y/l1, delta_Ek./abs(Ek)*100)

title('$\Delta E_{k\%} \ [\%]$');

colorbar('southoutside')

xlabel('$\frac{x}{l}$')

ylabel('$\frac{y}{l}$')

axis equal

xlim([min(min(a1/l1)), max(max(a1/l1))]);

ylim([min(min(y/l1)), max(max(y/l1))]);

grid on

I want to overlay the three graphs and make evident the common area under the 10% error (dark blue area). How can I do this?

Answer 1

[Adam Danz]

It sounds like you want to overlay three contours in one axes while being able to see through the 3 layers. Since all 3 of your contours have the same x and y extents, you can simply plot all three to the same axes and set the Face and Edge Alpha properties to add partial transparency.

figure()
axes()
contour(__,'FaceAlpha',0.33,'EdgeAlpha',0.33)
hold on
contour(__,'FaceAlpha',0.33,'EdgeAlpha',0.33)
contour(__,'FaceAlpha',0.33,'EdgeAlpha',0.33)

[Andrea Cesaro]

Thank you, it isn't what I thought, but it is a good idea.