MATLAB: Imagesc() contour superposition

Question

Hi,

I am trying to plot a contour plot over an imagesc() plot.

I have the following code:

figure,
subplot(1,3,1);
xVal = 5;
[xSlVal,xSlice] = min(abs(xVal - xGrid2(1,:,1)));
norm_jet_xVeloc = velocityMag(:,xSlice,:)./max(max(max(velocityMag)));
veloc_mag_conotur = velocityMag(:,xSlice,:)./u;
imagesc(squeeze(zGrid2(:,1,1)),squeeze(yGrid2(1,1,:)),squeeze(norm_jet_xVeloc));
hold on
C = contour(squeeze(zGrid2(:,1,11)),squeeze(yGrid2(1,1,:)),squeeze(veloc_mag_conotur));
caxis([-0.5 0.5]);
colormap('gray');
set(gca,'YDir','normal');
pbaspect([6 40 1]);
xlim([ -3 3]);
ylim([ 0 40]);
xlabel('z (mm)');
ylabel('y (mm)');

I think that it is working however I can't see the contour lines over the imagesc() magnitude plot. Is there another way to plot contour for a different color?

Thanks for your help.

Answer 1

It is difficult to provide exact solution without the exact data but the following is a demo code which superimposes a contour() plot over an imagesc() plot while assigning different colormaps to each of them.

% Plot first data 
ax1 = axes; 
imagesc(ax1,imread('cameraman.tif'));
axis square; hold all;  
% Plot second data 
ax2 = axes; 
contour(ax2,imread('cameraman.tif'));
axis square; hold off;
% Only to reverse the y axis,
set(ax2,'ydir','reverse')
% Link axes 
linkaxes([ax1,ax2]) 
% Hide the top axes 
ax2.Visible = 'off'; 
ax2.XTick = []; 
ax2.YTick = []; 
% Add differenct colormap to different data if you wish 
colormap(ax1,'gray'); % Colormap for the imagesc plot
colormap(ax2,'hsv'); % Colormap for the contour plot