Extracting data from a graph image using 'ginput'

Hello,

I want to extract data using 'ginput' from an attached file.

[Changho LEE]

Your answer helped me a lot.

Thank you.

Answer 1

[Vishal Gaur]

Hi Changho LEE,

Firstly, you have to digitize your graph. You can find many methods on File Exchange - https://www.mathworks.com/matlabcentral/fileexchange/?term=digitize&sort=ratings_desc

Then you can use ginput.

[Changho LEE]

Hi Vishal Gaur,

Thanks for the kind answer.

I picked a tool that looks very useful (graph_picker) and tried it myself, but finally I don't know how to extract the data.

If you know how to do it, I would appreciate it.

See attached file for larger image.

Answer 2

[darova]

here is an example

x = rand(100,1);                % generate some data
y = rand(100,1);
plot(x,y,'.r')
p = ginput(1);  
d = pdist2([x y],p);            % find combination of distances
[~,ix] = min(d);                % index of closest poont
line(x(ix),y(ix),'linestyle','none','marker','o')
text(x(ix), y(ix),sprintf('%0.1f %0.1f',x(ix), y(ix)))

[Changho LEE]

I didn't adopt it, but it helped.

Thank you for your sincere answer.