MATLAB: How to scatter datapoint into an existing semilogplot

MATLABplotscattersemilogx

Hey,

I have got an existing semilogx plot with data from literature. Now i would like to scatter my own measurements into that existing figure. The problem is, that even two semilogx with hold on aren't possible without getting back to normal scaled axes. I need the scatter function to color my datapoints by a third variable. Is there a way to get this two plots in one figure?

Thanks!

Best Answer

Ok, I found the answer by myself

hold on
plot(x1,y1,x2,y2);
scatter(x3,y3,[],z3);
set(gca,'xscale','log')
grid on

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You can use Eigen decomposition to come up with the parameters for the ellipse. You then scale the size of the ellipse based on how many standard deviations you want to include. The components of the ellipse are computed from the eigen decomposition of your data matrix. I pretty much copied the code below from here.

%for demonstration, I generated some data: 100 points in 2D
X = normrnd(0,2,[100 2]);
%the mean should be at zero
Mu = mean(X);
X0 = bsxfun(@minus, X, Mu);
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%covers around 95% of population
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%inverse chi-squared with dof=dimensions
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D = diag(D);
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figure(1)
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hold on
scatter(X(:,1),X(:,2))
hold off

Best Answer

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