I would like to reproduce the following figure in MATLAB:

There are two classes of points with X and Y coordinates. I'd like to surround each class with an ellipse with one parameter of standard deviation, which determine how far the ellipse will go along the axis.

The figure was created with another software and I don't exactly understand how it calculates the ellipse.

Here is the data I'm using for this figure. The 1st column is class, 2nd - X, 3rd - Y. I can use `gscatter`

to draw the points itself.

```
A = [
0 0.89287 1.54987
0 0.69933 1.81970
0 0.84022 1.28598
0 0.79523 1.16012
0 0.61266 1.12835
0 0.39950 0.37942
0 0.54807 1.66173
0 0.50882 1.43175
0 0.68840 1.58589
0 0.59572 1.29311
1 1.00787 1.09905
1 1.23724 0.98834
1 1.02175 0.67245
1 0.88458 0.36003
1 0.66582 1.22097
1 1.24408 0.59735
1 1.03421 0.88595
1 1.66279 0.84183
];
gscatter(A(:,2),A(:,3),A(:,1))
```

FYI, here is the SO question on how to draw ellipse. So, we just need to know all the parameters to draw it.

**Update:**

I agree that the center can be calculated as the means of X and Y coordinates. Probably I have to use principal component analysis (`PRINCOMP`

) for each class to determine the angle and shape. Still thinking...