MATLAB: Circle in pcolor map with radius as half of map length

pcolor and circle

Hello, I want to plot pcolor
pcolor(X)
X=50 * 50 matrix
I wish to plot a circle within pcolor map; with centre as centre of circle; and radius as half of pcolor map.
I hope I am clear. Please help.

Best Answer

temp = -24.5:1:24.5;
mask = temp.^2 .' + temp.^2 > 24.5.^2;
Xt = X;
Xt(mask) = nan;
pcolor(Xt);