ELLIPSE:FIT
The order that the qualifiers appear is irrelevant. The order that the
command parameters appear is fixed.
xin yin { fraction } { a b cx cy angle } { npts } { xout yout }
The major axis and the centre are found by least squares fitting a
line through the data points. The ratio of the major axis radius to
the minor axis radius is found by computing the standard deviations
about the major and minor axes. The minimum value of the major axis
is found for each point so that the point will be inside the ellipse,
then a value for the major axis is picked so as to be greater than or
equal to the specified fraction of the values.
Syntax: ELLIPSE\FIT\FRACTION xin yin frac
The ellipse is fit to the data points such that the ellipse encloses
a certain fraction, frac, of the data points. The default value for
frac is 0.9 To override the default, use the \FRACTION qualifier and
enter your value for frac.
By default, the major axis radius, the minor axis radius, the coordinates
of the centre, and the angle of the fitted ellipse will be displayed on
the monitor screen. To suppress this use the \-MESSAGES qualifier.
Syntax: ELLIPSE\FIT\PARAMETERS xin yin a b cx cy angle
If the \PARAMETERS qualifier is used, output scalar names will be expected
to receive the resulting ellipse parameters: major axis radius, minor axis
radius, coordinates of the centre, and the angle of the major axis
(in degrees, measured from the horizontal).