Hi,

I just made a function to draw uncertainty ellipses defined by a

covariance matrix P:

def plotEllipse(pos,P,edge,face):

U, s , Vh = svd(P)

orient = math.atan2(U[1,0],U[0,0])

ellipsePlot = Ellipse(xy=pos, width=math.sqrt(s[0]),

height=math.sqrt(s[1]), angle=orient,facecolor=face, edgecolor=edge)

ax = gca()

ax.add_patch(ellipsePlot);

show()

return ellipsePlot

To use it: ellipsePlot=plotEllipse([x,y],P,'black','0.3')

Hope this helps,

Tinne

## ···

On Wed, Oct 28, 2009 at 9:06 AM, Eero Nevalainen <eero.nevalainen@...2844...> wrote:

Hi,

I need to draw error ellipses on a scatterplot. I'm guessing someone has

done this before.

I've found some examples, such as this one

http://matplotlib.sourceforge.net/examples/pylab_examples/ellipse_rotated.html

That led to the artist tutorial, and... ARGH! INFORMATION OVERFLOW!

Can someone explain to me, why I suddenly have to know so much about

matplotlib's internals to get an ellipse drawn?