Name

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      CIRRANGE

Purpose

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      To force an angle into the range 0 <= ang < 360.

Calling Sequence

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      CIRRANGE, ang, [/RADIANS]

Inputs/output

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      ang - The angle to modify, in degrees. This parameter is
                changed by this procedure. Can be a scalar or vector.
                The type of ANG is always converted to double precision
                on output.

Optional Input Keywords

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      /RADIANS - If present and non-zero, the angle is specified in
                radians rather than degrees. It is forced into the range
                0 <= ang < 2 PI.

Procedure

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      The angle is transformed between -360 and 360 using the MOD operator.
      Negative values (if any) are then transformed between 0 and 360

Modification History

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      Written by Michael R. Greason, Hughes STX, 10 February 1994.
      Get rid of WHILE loop, W. Landsman, Hughes STX, May 1996
      Converted to IDL V5.0 W. Landsman September 1997