delta=0.2; 
D = -2.5:delta:2.5; 
N=10;
[X,Y,Z] = peaks(D);
V=[-5 -4 -3 -2 -1 0 1 2 3 4 5];
figure(1)
[C,h] = contour(X,Y,Z,V);
clabel(C,h,V)
axis square






