MATLAB: Finding the error between two curves from a fig

errorfigureMATLAB

I have a fig, the onee in attaced (example).
Considering the green one the true value, how can I evaluete the error of the second?
P.S.
I have Matlab 2014b

Best Answer

I used the findall function to find out what was plotted.
I noticed that some of the lines containing the NaN values were plotted as nonsense.
The lines you're trying to compare are probably h(2) and h(6).
In addition, the blue line contains NaN values that need to be removed.
Finally, we need to align the number of elements to compute the error, so we interpolate.
% get current axes 
ax = gca;
% find object
h = findall(ax);
% get Y data of green and blue lines 
GreenLineX = h(2).XData; 
GreenLineY = h(2).YData; 
BlueLineX = h(6).XData;
BlueLineY = h(6).YData;
% eliminate NaN
BlueLineX = rmmissing(BlueLineX);
BlueLineY = rmmissing(BlueLineY);
% interpolation
GreenLineY_interp = interp1(GreenLineX,GreenLineY,BlueLineX,'spline'); 
% MSE
MeanSquaredError = mean((GreenLineY_interp - BlueLineY).^2);
figure
plot(GreenLineX,GreenLineY,'-g');
hold on
plot(BlueLineX,BlueLineY,'-b');
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