Adding systematics to contour ellipses


I have two variables which come from a fit, and I am trying to plot the 2D contour of their measures along with the correlation.
Just for the statistical error part I have found at least three solutions: minuit->Contour, RooEllipse and a normal TEllipse in which I define the properties by hand.

The problem is that I have also a systematic (assymetric) error in each measurement, and this errors also may have a different correlation between them, and this error comes from a different program plus literature, so I have to put it by hand.

So, is there any predefined way to do this (assymetric ellipse contour with parameters defined by hand), and if not does anyone know what would be the best way to implement it? I have been trying to do 4 different TEllipse each spanning 90 degrees but this approach doesn’t work because the contour line is not continuous at the junctions


I wonder if knowing the functional form of the ellipse-sections you have in mind, you could generate TGraph’s, then overlay them onto your canvas?


I was kind of stuck on the idea of making ellipses work, but making a graph with N points where I loop in the angle and calculate a distance from the center might be a better idea. I will see if I can do that.