# Find the coordinates of a point chosen on a plot

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Nom on 12 Nov 2019
Commented: Fangjun Jiang on 9 May 2023
Hello,
So I've been using ginput to select points on a plot
My plot consists of time(x) and velocity(y).
Below is my user-selected points.
[Userx,Usery] = ginput(1);
However, I noticed it doesn't actually select points from the voltage vs. time graph and instead just a point in the figure screen.
How can I get the nearest data point of the actual plot?
I've found one solution is to use this user created script file:
https://www.mathworks.com/matlabcentral/fileexchange/3265-magnetginput
Dinuka Madhumal on 9 May 2023
Can anyone help me, what is the problem of this error - Undefined function or variable 'pdist2'. . Do i want to make the 'pdis2' function ?

darova on 14 Nov 2019
Short example
x = linspace(0,2,20)'; % generate some data
y = sin(x);
plot(x,y,'.-b')
xy = ginput(1); % get point
[~,ix] = min(pdist2([x y],xy)); % find closest point
hold on
plot(x(ix),y(ix),'or') % display closest point
hold off
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Dinuka Madhumal on 9 May 2023
Can anyone help me, what is the problem of this error - Undefined function or variable 'pdist2'. . Do i want to make the 'pdis2' function ?
Fangjun Jiang on 9 May 2023
pdist2() comes from Statistics and Machine Learning Toolbox.

Fangjun Jiang on 12 Nov 2019
Use data cursor, set "SnapToDataVertex" to be "on" and then get the position. See example in
doc datacursormode
Nom on 13 Nov 2019
Edited: Nom on 13 Nov 2019
Is there a way to do this using ginput, at least where I can see the x-line and y-line of the crosshair which chooses the point?

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