Plotting the resual difference between two plots, example picture in the thread.

Hi

Im doing data fitting and am interested in plotting a line from the data to the fitted curve, see wikipedia image.

http://upload.wikimedia.org/wikipedia/commons/1/17/MDKQ1.svg

Thats exactley what i want i just cant seem to plot the residuals like they have done.

This is my code

clear, clc
x = 0:pi/10:2*pi;
y = sin(x);
yx = random('ev',y,0.2);
plot(x,y,x,yx,'o'), axis([0-0.1 2*pi+0.1 min(yx)-0.1 max(yx)+0.1])

thanks

Answer 1

[Matt Kindig]

Add to your code:

hold on;
line([x;x], [yx;y],'color','green');
plot(x,yx,'bo','markerfacecolor','blue');

You can tweak the colors as necessary.

Answer 2

[Mamed]

Thanks a lot work like a charm. I will post full code below for future readers.

clear, clc, clf

x = 0:pi/16:2*pi;

y = sin(x);
yx = random('norm',y,0.2);

subplot(2,1,1)
plot(x,y),hold on, axis([0-0.1 2*pi+0.1 min(yx)-0.1 max(yx)+0.1])

plot(x,yx,'r*')%,'markerfacecolor','red');
line([x;x],[yx;y],'LineStyle','-.', 'color','black');
hline = refline([0 0]), set(hline,'Color','k')
title('Curve Fitting Example') 
legend('Fitted Curve','Sampled Values','Residuals'), hold on

subplot(2,1,2)

stem(x,yx-y,'b*'),axis([0-0.1 2*pi+0.1 min(yx)-0.1 max(yx)+0.1])
legend('Residuals'), title('Comparable Values of the Residuals')