SUBROUTINE AREANAV2(IAREA,PARAM,ICALB)
C     SUBROUTINE MAIN0
C
C  Subroutine to get navigation and calibration.
C  By Lance Braunstein and Gary Gray, Hughes STX.
C
      INTEGER IAREA, DIREC(64),NAVSIZ, PARAM(128), CALSIZ, ICALB(128)
      INTEGER  LCOR ,ECOR ,NLIN ,NELE ,LRES ,ERES ,ZRES ,ZSIZ ,NCHAN ,
     1   SRCTP, CALTP, LPREF, NELER
C
C  Get the AREA NUMBER (when run as a MAIN), PUT IN 'IAREA'.
C     IAREA = IPP(1,0)
C
C---READ AREA DIRECTORY
C READD READS AREA DIRECTORY INTO DIREC.
      CALL READD (IAREA,DIREC)
C---NUMBER OF LINES AND ELEMENTS & BYTES PER DATA ELEMENT
      NLIN = DIREC(9)
      NELE = DIREC(10)
      ZSIZ = DIREC(11)
C---Z RESOLUTION, NUMBER OF BANDS OR ELEMENTS.
      ZRES = DIREC(14)
C---NUMBER of BYTES in PREFIX (MULTIPLE OF 4).
      LPREF = DIREC(15)
C---INITIALIZE AREA
C     CALL OPNARA(IAREA)
C PUT NAVIGATION PARAMETERS INTO 'PARAM'
C DIREC(35) is the word that contains the byte location (0-based) of
C the start of the navigation block in the file. Its length should be
C 128 words or extend to DIREC(63) where the calibration part is.
      NAVSIZ = DIREC(63) - DIREC(35)
      IF (DIREC(63).EQ.0) NAVSIZ = DIREC(34) - DIREC(35)
      CALL ARAGET(IAREA,DIREC(35),NAVSIZ,PARAM)
C Put NAVIGATION FILE 'PARAM' INTO SLOT 2.
      ISTAT = NVPREP (2,PARAM)
      IF (ISTAT .NE. 0) GO TO 902
C Get CALIBRATION CODICILS IF present.
      CALSIZ = DIREC(34) - DIREC(63)
      IF (CALSIZ .GT. 0) THEN
       CALL ARAGET (IAREA,DIREC(63),512,ICALB)
      END IF
C
      RETURN
 902  WRITE (6,6902) ISTAT
 6902 FORMAT(' NVPREP FAILED, ISTAT= ',I4)
      RETURN
      END