Changing color map to show different points in a matrix

I have a matrix of size a = (45x45), I am trying to plot it using contourf(). I am having a problem when I apply colorbar and colormap to my data because it does not represent all the values present in the data, instead it just shows the highest and lowest value. If my data is in the range [-1 1], it just shows that every thing is just -1 or 1. I am using 'jet' colormap. Whenever I plot it using surf() function it shows all the different values with different colors which is what i want but I want it in 2D and also I dont want the mesh in it.

here is the code I have:

contourf(a);                       
    title('a');
    colormap(jet(128));
    caxis([-1 1]);
    colorbar;

Any help would be appreciated.

Thank you.

[Walter Roberson]

pcolor() is the 2D equivalent of surf() -- in fact pcolor() is implemented as a call to surf() followed by a call to change the view to 2D.

What is class(a), and what is min(a(:)) and max(a(:)) ?

[Raza]

Thank you Walter!!!

a is a double (45x45)

max = 15

min = -5

I just tried pcolor and it worked just fine for me.

however, when I tried to eliminate the mesh lines using shading interp the plot becomes blurry and doesnt give as much resolution.

[Walter Roberson]

h = pcolor(a); h.EdgeColor = 'none'

[Raza]

Thank you for your help Walter, I will try that.