ELLIPSE

        [GREG2\]ELLIPSE Major [Minor [Position_Angle]] [/BOX X Y] [/USER X Y
    [code]] [/ARC Theta_min Theta_max] [/FILL [Colour]]

    This command draws at current pen position  (or  at  position  (X,Y)  if
    option  /BOX  or  /USER is present) an ellipse of given semi-major axis,
    semi-minor axis, (default Minor = Major) and  PositionAngle  (default  0
    degrees).

    Major, Minor, X and Y are in User  Coordinates,  but  Position_Angle  is
    ALWAYS in DEGREES, TRIGONOMETRIC ORIENTATION. Major, Minor, X and Y, can
    be  1-D  arrays  of  any  size,  provided  the  sizes  are   the   same.
    Position_Angle can be indifferently an array, a number, or omitted.

    The code suboption in the /USER  option,  if  present,  can  be  any  of
    `SECONDS',  `MINUTES',  `DEGREES',  `RADIANS' (in which case the X and Y
    coordinates are taken to be in the corresponding unit) or `ABSOLUTE' (in
    which  case  X and Y are taken as absolute coordinates, usually exprimed
    in sexagesimal format). The presence of the code suboption is valid only
    if a PROJECTION and a SYSTEM (EQUATORIAL or GALACTIC) are both defined.

    A portion of the ellipse can be drawn by specifying the boundary  angles
    in  option  /ARC  (in  degrees,  trigonometric  sense  from the position
    angle). Not compatible with the array mode.

    Option /FILL [Colour] will fill the  ellipse(s),  with  the  current  or
    specified colour. If the /ARC option is also present, the filled area is
    the corresponding pie part, not the subtended arc.

    This command is useful for plotting beam  sizes,  incertainty  ellipses,
    pie charts, etc...