Parameters

 Keyword   Posn    Type      Description
 -------   ----    ----      -----------
 INP         1     UNIV      Input Dataset
              -GLOBAL.EVDS (Default event dataset)
 OUT         2     UNIV      Dataset for output
              ->GLOBAL.EVDS (Default event dataset)
 ANNULUS     -     LOGICAL   YES = annular, NO = circular region
        Hidden default = NO
 XCENT       3     REAL      x-coord of centre of region
 YCENT       4     REAL      y-coord of centre of region
 OUTER       5     REAL      Outer radius of region
 INNER       6     REAL      Inner radius of annular region