I want to make a 2D plot of points with different x, y coordinates and have colors depending on a separate variable. I have make column vectors for x and y coordinates and another column containing 1 or -1. I would like to represent the points with 1 as red and -1 as blue points. I have codes as follow: Code (Matlab M): x_dis=rho_rec(1:nDis,xCol,step);%x coordinates y_dis=rho_rec(1:nDis,yCol,step); %y coordinates bv=rho_rec(1:nDis,bvCol,step); % 1 or -1 for i=1:1:nDis if bv(i)==1 dis_color(i,1:3)=[0 0 1]; %blue elseif bv(i)==-1 dis_color(i,1:3)=[1 0 0]; %red end end plot(x_dis,y_dis,'.','Color',dis_color(1:nDis,:)) However it doesn't work. How should I modify the code? Thank you.