# how to save coordinates in a text file?

7 views (last 30 days)
youssef hany on 15 Sep 2022
Answered: William Rose on 17 Sep 2022
I've used ''inpolygon'' function and I want to save the red points in a txt file in form of 2 columns of x and y, for ex. :
-1.21 3.24
-1.56 3.52
how can I do that? I'm new to matlab :D
The inpolygon function:
xv=B(:,1)';yv=B(:,2)';
xq=p(:,1)';yq=p(:,2)';
[in,on] = inpolygon(xq,yq,xv,yv);
William Rose on 17 Sep 2022
@youssef hany, @Rik is offering a hint which sounds good to me. You said "that's not what I want", but since you want to "save the filtered points in a text file", @Rik is right (as usual).

William Rose on 17 Sep 2022
I do not see the matrix of selected points which you want to save. Maybe that is the problem. Here is an example:
N=100; %total number of points
xq=rand(N,1); yq=rand(N,1);
xv=[.5 .9 .5 .1 .5];
yv=[.1 .5 .9 .5 .1];
in=inpolygon(xq,yq,xv,yv);
plot(xq,yq,'bo',xq(in),yq(in),'rx',xv,yv,'--r');
a=[xq(in),yq(in)];
writematrix(a,'a.txt')
Try that. It should save the coordinates of the selected points as a 2-column text file.

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