Extracting 'y' values from plot over an iterating loop

2 次查看(过去 30 天)
Hello All,
I am trying to extract y values from a plot in matlab. I have used the below code snippet. However, as I have a for-loop iterating (which is needed as I need those values), it keeps giving me an "error using interp1- X must be a vector of numeric coordinates". Any suggestions? Thanks!
figure(107);
for i = 1:25
p1 = loglog(Frequency{i,:},Svg{i,:}); %%%%,'Color',map(i,:)); %%%
LineH = get(gca,'children');
freq=get(LineH,'XData');
psd=get(LineH,'YData');
freq_10 = 10; % the x value for which I need the y value
svg_10{i} = interp1(freq,psd,freq_10);
hold on;
end
  4 个评论
Elias Gule
Elias Gule 2016-5-25
Try using
LineH = findobj(gca,'Type','line'); % All line objects of the current axes
LineH = LineH(i); % Handle for the current line object
Adam
Adam 2016-5-25
If you want to extract things from a line graphics object though by far your best option is to just retain the line handle when you plot it. It is more efficient than having to search the scene for it afterwards.

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回答(1 个)

Adam
Adam 2016-5-25
Well if freq and psd are 2d matrices then
interp1(freq,psd,freq_10);
is not going to work because interp1 expects vector inputs not a matrix. You should be able to use interp2 on it though, just making sure that in the second dimension your input and output grids are the same so that you don't interpolate in that direction.
Maybe you just meant to use this instead?
svg_10{i} = interp1(freq(i,:),psd(i,:),freq_10);
  2 个评论
Kash022
Kash022 2016-5-26
Hello@Adam: yes, I tried this exactly...but to no use
Adam
Adam 2016-5-26
In what sense? Do you get the same error message? Your inputs to interp1 should at least be vectors in this case.

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