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How to get data from figure?

Asked by Deniz on 10 Nov 2013
Latest activity Answered by Walter Roberson on 11 Nov 2013

Hi,

I have a curve figure. How can i get the y-data (vector) for given x=linspace(0,R,c) out of figure?

Thanks

0 Comments

Deniz

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3 Answers

Answer by Walter Roberson on 11 Nov 2013
Accepted answer
xd = get(get(gca,'children'),'xdata');  % return the plot data
yd = get(get(gca,'children'),'ydata');
x = 1 : 0.1 : 3;   %places to sample at
y = interp1(xd, yd, x);    %interpolate from stored data at locations to be sampled

0 Comments

Walter Roberson
Answer by dpb on 10 Nov 2013
x = get(get(gca,'children'),'xdata');  % return the plot data
y = get(get(gca,'children'),'ydata');
y=y(x(x==linspace(0,R,c)));

Trivial example from keyboard to illustrate...

>> plot(rand(1,3))
>> xdat=get(get(gca,'children'),'xdata');
>> ydat=get(get(gca,'children'),'ydata');
>> xvec=linspace(0,1,2);
>> y=ydat(ismember(xdat,xvec))
y =
  0.8147
>> 

You'll get some other value depending on state of rng at the time but the process should be clear to retrieve the data from the plot and find a location.

NB that if your x values are non-integer values you may need to make the comparison "fuzzy" rather than exact as is shown here.

0 Comments

dpb
Answer by Deniz on 10 Nov 2013

this solution doesn't work for me.

plot(rand(1,3))

xdat=get(get(gca,'children'),'xdata')

ydat=get(get(gca,'children'),'ydata')

xvec=linspace(1,3,0.1)

y=ydat(ismember(xdat,xvec))

what i get:

xdat =

     1     2     3

ydat =

    0.0462    0.0971    0.8235

xvec =

   Empty matrix: 1-by-0

y =

   Empty matrix: 1-by-0

I need the y-vector for a x-vektor:xvec=linspace(1,3,0.1)

Any other ideas?

Thanks

1 Comment

Walter Roberson on 11 Nov 2013

The last argument to linspace() needs to be a count, not an increment. Use ":" if you want an increment

1 : 0.1 : 3
Deniz

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