Fitted Ellipse and its major axis

[Stefan van der Walt]

Hi Adrián

On 2015-05-12 15:55:45, Adrián Galdrán <agaldran at gmail.com> wrote:
> I have been trying to fit an ellipse to the border of a roughly 
> elliptic region. The ellipse fits nicely, but whenever I try to 
> plot the major axis, it fails. Of note, the approach below works 
> well for phi \in [pi/4, 3pi/4], but not on other 
> semi-cuadrants. I think the problem lies on the output of xc, 
> yc, a, b, alpha = ellipse.params. Here, xc and yc are the 
> coordinates of the center of the ellipse, a and b are the length 
> of major and minor axis, and alpha is (I guess) the angle that 
> the major axis makes against the horizontal axis.

Have a look at:

http://stackoverflow.com/a/28289147/214686

Perhaps that helps?  We also have examples in the documentation on 
how to plot these axes.

Regards
Stéfan