Drawing line through scatter plot

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Walter Mabry
Walter Mabry on 14 Oct 2021
Edited: Walter Mabry on 14 Oct 2021
clear
I = imread('star.png');
[r,c,nc] = size(I);
GC = I(:,:,2);
BI = GC < 200;
[y,x]=find(BI);
y=y*-1; x=x*-1;
c = linspace(1,10,length(x));
figure
plot(x,y,'.')
The code plots the folowing graph
I want to make on continuous line that produces the same image. So basically x an y cordinates for a line that traces this star.
EDIT: Also wanted to mention that I have tried implementing a polyfit--> polyval rountine but It has not given me the desired results.
  2 Comments
Matt J
Matt J on 14 Oct 2021
Your code doesn't run to completion:
I = imread('star.png');
[r,c,nc] = size(I);
GC = I(:,:,2);
Index in position 3 exceeds array bounds. Index must not exceed 1.
BI = GC < 200;
[y,x]=find(BI);
y=y*-1; x=x*-1;
c = linspace(1,10,length(x));
figure
plot(x,y,'.')
Walter Mabry
Walter Mabry on 14 Oct 2021
Matt,
Thanks for the commetn here. Depending on the image you might have to change that line. It will do the same if you put
I(:,:,1)

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