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Display the vertex in RooEllipse


I’m trying to plot an ellipse using RooEllipse and I want the vertex to plotted as well:

RooEllipse *el = new RooEllipse("",0.0039,-0.0002,0.0033,0.0036,0.13,100);

Is it possible to display the vertex of this ellipse? A marker at (0.0039,-0.0002)
Any help is highly appreciated.



_ROOT Version: 6.20.06
_Platform: Ubuntu 18.04

RooEllipse is a TGraph so the option “P” in te Draw directive will plot markers.

Thank you very much for your help @couet,

The markers are displayed now. But I want also to display the point at the center (0.0039,-0.0002) of the ellipse. This center marker is need because it is my reference for the uncertainty values. Is there a workaround on this?

Thanks again,


The ellipse center is not part to the graph data points. To display it you will need to draw a TMarker at the center coordinates.

Many thanks for your help @couet. It works fine now.