Modified contour plot with different functions

I was wondering how to create a contour plot with the following specifications:

I have two variables x and y and two functions of these variables f(x,y) and g(x,y) and I want to plot f(x,y) in a contour plot. However I want to highlight those areas where g(x,y)>f(x,y). Of course I could graph something like h = g-f and see where it is positive but I think the first option is better. I would very much appreciate if someone could help me with this.

Answer 1

[KSSV]

[X,Y,Z] = peaks(100) ;   % let this be g 
idx = Z>3 & Z<5 ;        % a given condition 

contour(X,Y,Z)
hold on
plot(X(idx),Y(idx),'*r')

[AlphaReign]

I see your point, but the condition I need is based on another function, so that I can't really implement this. Any idea of how could I express that: idx = Z > F ?

Thank you very much.

[KSSV]

I can't really implement this why not?

It is straighforward as I have shown the above code.

idx = Z>F ; 

[AlphaReign]

The logical condition returns a matrix idx with 0's and 1's whereas X and Y are vectors, therefore they're out of the arrays bounds.

[KSSV]

sconvert x,y to matrices.....using meshgrid.

[AlphaReign]

Got it! Thank you very much :)

[KSSV]

Thanks is accepting the answer..:)