Issue: Fitting a set of datapoints to Ellipse and Plotting it to visualise the result

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sri harsha chilakamarri on 18 Nov 2018

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https://in.mathworks.com/matlabcentral/answers/430574-issue-fitting-a-set-of-datapoints-to-ellipse-and-plotting-it-to-visualise-the-result

Commented: sri harsha chilakamarri on 19 Nov 2018

forums1.txt

Hi,

My coordinates data and the image (currently, which I am getting as output are attached above)

I'm trying to fit some datapoints using the code from the link https://en.mathworks.com/matlabcentral/fileexchange/22423-ellipse-fit

After fitting the data, I am trying to plot the correct ellipse, in contrast to my point data.

Somehow I'm getting the ellipse orientation different. (As attached in the image)

I would be glad if you can have a look at my code below (I am attaching text file below).

data = load (textfile);
scatter (data (:, 1), data (:, 2), 'r' );
hold on ;
[semimajor_axis, semiminor_axis, x0, y0, phi] = ellipse_fit (data (:, 1), data (:, 2));
% [a, b, c, d, f, g] = ellipse_fit (data (:, 1), data (:, 2));
Z = [x0 y0];
A = semimajor_axis;
B = semiminor_axis;
ALPHA = phi;
plot ellipse (Z, A, B, ALPHA);