Displaying angles in radians

Displaying angles in units of hours, degrees, minutes or seconds, optionally formatted as sexagesimal values is usually the required behaviour. However, occasionally you may want to display angles as simple decimal numbers expressed in radians. CAT also provides this facility. It can be configured so that CAT_EGT0F returns an angle expressed in radians, written into a CHARACTER string using the Fortran 77 external format specifier for the column (defined by attribute EXFMT). In this case CAT is treating columns of angles just like any other column; CAT_EGT0F simply writes the value into a CHARACTER string using the external display format specifier.

To control whether angles are converted to hours, degrees, minutes or seconds and optionally formatted as sexagesimal values or simply written as a decimal number in radians you must set a configuration (or `tuning') parameter in CAT. This parameter is called `ANGLE_LIST' and is set using routine CAT_TUNES. Proceed as follows.

• to configure CAT to return angles as radians:

  CALL CAT_TUNES ('ANGLE_LIST', 'RADIANS', STATUS)

• to configure CAT to return angles as hours, degrees, minutes or seconds, optionally formatted as sexagesimal values:

  CALL CAT_TUNES ('ANGLE_LIST', 'SEXAGESIMAL', STATUS)

Once one of these alternatives has been set it will remain in effect until another call is made to CAT_TUNES to reset it. The default if the representation is never explicitly set is that angles are converted to hours, degrees, minutes or seconds and optionally output as sexagesimal values.

You can inquire the current value of tuning parameter `ANGLE_LIST' using routine CAT_TUNEG:

     CHARACTER
    :  TVALUE*75   ! Current value for angle representation.
      .
      .
      .


     CALL CAT_TUNEG ('ANGLE_LIST', TVALUE, STATUS)

and TVALUE will be returned set to `RADIANS' or `SEXAGESIMAL', as appropriate.