ELLIPSE

        [GREG2\]ELLIPSE Major [Minor [Position_Angle]] [/BOX X Y] [/USER X Y
    [code]] [/ARC Theta_min Theta_max] [/FILL [Colour]] [/HATCH [Ipen]  [An-
    gle] [Separ] [Phase]]

    This  command draws at current pen position (or at position (X,Y) if op-
    tion /BOX or /USER is present) an ellipse of given semi-major axis,  se-
    mi-minor axis, (default Minor = Major) and Position_Angle (default 0 de-
    grees).

    Major, Minor are in User Coordinates, but Position_Angle  is  ALWAYS  in
    DEGREES, TRIGONOMETRIC ORIENTATION. X and Y are in User Coordinates (op-
    tion /USER) or in Physical Units (centimeters from the bottom  left  box
    corner,  option  /BOX).  Major, Minor, X and Y, can be 1-D arrays of any
    size, provided the sizes are the same. Position_Angle can  be  indiffer-
    ently an array, a number, or omitted.

    The  code suboption in the /USER option, if present, can be any of `SEC-
    ONDS', `MINUTES', `DEGREES', `RADIANS' (in which case the X and Y  coor-
    dinates  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  an-
    gle). Not compatible with the array mode.

    Option  /FILL  [Colour]  will  fill  the ellipse(s), with the current or
    specified colour. Option /HATCH will fill them with parallel lines (pen,
    angle,  separation and phase can be customized, defaults are current, 45
    degrees, 0.25 cm and 0 respectively); in this case  the  contour(s)  are
    not  drawn.  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,  uncertainty  ellipses,
    pie charts, etc.