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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  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, X and Y are in User Coordinates, but Position_Angle is AL-
    WAYS in DEGREES, TRIGONOMETRIC ORIENTATION. Major, Minor, X and  Y,  can
    be 1-D arrays of any size, provided the sizes are the same. Position_An-
    gle 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.

    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,  uncertainty  ellipses,
    pie charts, etc.


Gildas manager 2011-09-07