function overlaycasts(x,zmax);

% overlaycasts(x,zmax)
% overlay the positions of the casts.

isheld=ishold;
hold on;
for i=1:length(x);
    if (zmax(i)>1000) colr=[1 1 1];
    else colr=[.5 .5 .5];
    end;
    plot([x(i) x(i)],[0 zmax(i)],'color',colr);
end;
if ~isheld
    hold off;
end;