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        [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). This command is useful for plotting beam sizes, uncertainty  el-
    lipses, pie charts, etc.

    Major,  Minor  are  in User Coordinates. X and Y are in User Coordinates
    (option /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.

    starting 0 from X>0 half-axis. Trigonometric means it increases from X>0
    half-axis to Y>0 half-axis. As such, orientation  can  go  clockwise  or
    counter-clockwise  depending  if the axes are reverted or not, like e.g.
    for astronomical plots (X increase to the left). The Position_Angle  can
    be indifferently 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.

    /FILL [Colour] will fill the ellipse(s), with the current pen colour  or
    with the specified colour (see HELP PEN /COL for possibilities). If /ARC
    is also present, the filled area is the corresponding pie part, not  the
    subtended arc.

    /HATCH  will  fill  the ellipse(s) with parallel lines. The pen (default
    current), line orientation in degrees (default 45),  the  separation  in
    physical  units  (default 0.25 cm) and phase between 0 and 1 (default 0)
    can be customized. In this case the contour(s) are not drawn. If /ARC is
    also  present,  the  filled  area is the corresponding pie part, not the
    subtended arc.

Gildas manager 2020-12-02