How to overlay a pcolor plot with a contour plot that uses a different colormap?

Question

Minimum example that does not achieve it:

[X,Y,Z] = peaks;
figure;
pcolor(X,Y,Z);
shading flat;
hold all;
axes;
contour(X,Y,Z);
colormap gray;  % this should         


        

Answer 1

You can fix the problem by catenating two colormaps, and making sure that the values of the functions are such that they access the right part of the colormap:

cm = [jet(64);gray(64)];
figure,
pcolor(X,Y,Z)
shading flat
hold on
%# Z in the contour starts after the maximum
%# of Z in pcolor
contour(X,Y,Z-min(Z(:))+max(Z(:))+2,'LineWidth',2)
%# apply the colormap
colormap(cm)

For a more convenient solution, you may also want to have a look at this file exchange pick of the week