contourf color map scale

Hello everybody

I am trying to plot using contourf. I need the background as white.

Sample code is as follows:

[X,Y] = meshgrid(-3:.2:3,-3:.2:3);

Z = X.^2+Y.^2;

v = 2:0.2:20;

length(v)

contourf(X,Y,Z,v)

This works well. But when I add

shading flat

it gives following error

Warning: Patch FaceVertexCData length (1) must equal Vertices length

(61) for flat EdgeColor.

Does anybody have a solution.

Thanks in advance

TS

http://matlab.itags.org/q_matlab_9963.html