rope.m

ROPE Generate coordinates of an ellipse enclosing data.

ROPE Generate coordinates of an ellipse enclosing data.

[LX,LY]=ROPE(X,Y,LEVEL) returns coordinates [LX,LY] of an ellipse enclosing LEVEL % of the coordinate pairs in column vectors X and Y.

The major axis of the ellipse is the straight line regression of Y on X. The centre of the ellipse is the mean of X and Y and the ratio of the major to minor axes is the ratio of the standard deviations of the data points' distances from the centre, projected onto the major and minor axes.