# How do I extract data points from a plot?

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MathWorks Support Team
on 24 Jul 2013

Commented: Walter Roberson
on 5 Apr 2021

I would like to extract data points from a plot.

### Accepted Answer

MathWorks Support Team
on 17 Mar 2021

Edited: MathWorks Support Team
on 17 Mar 2021

You can get the data from a plot by accessing the XData and YData properties from each Line object in the axes.

1. Make the figure containing the plot the current figure. An easy way to do this is to click the figure to bring it to the foreground.

2. Call the gca command to get the current axes within that figure. Then pass the axes to the findobj function to search for all lines in the axes. For example, here is a plot containing one line.

figure

plot([1 2])

ax = gca;

h = findobj(gca,'Type','line');

3. Get the coordinates from the XData and YData properties of the Line object.

x = h.XData;

y = h.YData;

If the plot has multiple lines, h is returned as an array of Line objects. Use array indexing to access each Line object in h. Then you can get the XData and YData properties from each Line object.

For example, here’s a plot containing three lines.

figure

plot([1 2 3; 4 5 6])

ax = gca;

h = findobj(gca,'Type','line');

x1 = h(1).XData;

y1 = h(2).YData;

x2 = h(2).XData;

y2 = h(1).YData;

x3 = h(3).XData;

y3 = h(3).YData;

##### 9 Comments

Walter Roberson
on 5 Apr 2021

Suppose you have two graphics objects h1 and h2, both of them with increasing X values, but the X values might not be exactly the same. For example, the second X series might be roughly 3 milliseconds after the first X series because of time spent acquiring the data.

In such a case, to align the data values:

x1 = h1.XData;

y1 = h1.YData;

x2 = h2.XData;

y2 = h2.YData;

y2aligned = interp1(x2, y2, x1, 'linear', 'extrap');

Now you have

x1 -- used for both sets of data

y1 -- y for the first set of data

y2aligned -- y for the second set of data, calculated at common time x1

### More Answers (7)

Rakesh M
on 4 Jun 2020

##### 0 Comments

MANIMARAN SELVAM
on 2 Nov 2015

how to extract points from the output PV and IV graph

##### 1 Comment

Walter Roberson
on 2 Nov 2015

Edited: MathWorks Support Team
on 24 Nov 2020

Stefanos Doltsinis
on 16 Apr 2016

that code works nicely!

I just have one issue. I want to extract data from a subplot(2,1) and the extracted data are only from the second plot. How can I receive data from the first plot?

@MANIMARAN SELVAM I want to extract data from the same plot as you want (Photovoltaic array simulink module) and the code above works fine. At least for the Power against Voltage diagram. The data you need will be in x in the form of an array and will have the following sequence x{1} is the maximum voltage x{2} is the maximum power x{3} are all the data points on the graph.

I hope this helps.

##### 1 Comment

Walter Roberson
on 22 Apr 2016

In the above code, replace the line

h = findobj(gca,'Type','line')

with

h = findobj(subplot(2,1,1),'Type','line')

swagatika panigrahi
on 13 Feb 2017

##### 3 Comments

Akib Rahman
on 25 Oct 2018

Akshay Kumar
on 8 Jul 2018

##### 0 Comments

Adarsh Vasa
on 13 Apr 2020

##### 0 Comments

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