FUNCTION {{p}}zone_lookup
  IMPORTING
    iv_postcode TYPE string
  EXPORTING
    ev_zone TYPE string.

  DATA lv_first TYPE c LENGTH 1.

  CLEAR ev_zone.
  IF iv_postcode IS INITIAL.
    RETURN.
  ENDIF.

  lv_first = substring( val = iv_postcode off = 0 len = 1 ).

  CASE lv_first.
    WHEN '0' OR '1'.
      ev_zone = 'N'.
    WHEN '2' OR '3'.
      ev_zone = 'W'.
    WHEN '4' OR '5'.
      ev_zone = 'C'.
    WHEN '6' OR '7'.
      ev_zone = 'E'.
    WHEN '8' OR '9'.
      ev_zone = 'S'.
    WHEN OTHERS.
      CLEAR ev_zone.
  ENDCASE.

ENDFUNCTION.