errbar — add vertical error bars on a 2D plot
errbar(x,y,em,ep)
errbar adds vertical error bars on a 2D plot.
x and y have the same meaning as in plot2d.
em(i,j) and ep(i,j) stands for the error interval on the
value y(i,j): [y(i,j)-em(i,j),y(i,j)+ep(i,j)].
Enter the command errbar() to see a demo.