Langley DAAC Version Number: LD_008_003_001_00_00_0_19990415

The FORTRAN program isccp_dx_read.f has been provided by the data
producer as a sample program.  It is up to the user to modify the 
program to output the data of interest.  

The program can be compiled with a simple f77 command line argument.
A sample of the compilation output a user can expect to see follows:

% f77 -o rd_pgm isccp_dx_read.f
isccp_dx_read.f:
 MAIN:
  dxtabs:
  dxopen:
  dxread:
 BLOCK DATA:

Prior to running the program, there must be an input file named
fort.10 available.  This file is what the program will open and 
read.  There are several ways to create this file:

a)  copy one of the ISCCP DX Native data files to filename fort.10
b)  rename the ISCCP DX Native data file to fort.10
c)  use the unix "ln" command to create a symbolic link named fort.10
    which points to the data file.

We recommend the unix "ln" command for the following reasons:

a)  a copy of the file will require additional disk resources
b)  renaming data files can become confusing
c)  soft links can point to different directories and disk partitions

A sample of the "ln" command follows:
    
%ln -s /datadir/ISCCP/dx_910405_gmt0_nat fort.10
%ls -l fort.10
lrwxrwxrwx  1 ownername  10 Apr 22 15:57 fort.10 -> /datadir/ISCCP/dx_910405_gmt0_nat
%

After the program has been successfully compiled and the file fort.10
has been created, the read program can be executed.  A sample of the output 
follows:

% rd_pgm

DX HEADER:  YEAR 1991 MONTH  4 DAY  5 GMT  0 SATID 43 SATTYP 0 NCHANS 3 NITIMG  1
LON LAT IPOS JPOS  104  1002  250  250
LNDWTR HITOPO SHORE    0  0  0
DAYNIT SNOICE GLINT    1  0  255
MUE    MU0    PHI      95  255  255
ITHR   VTHR   CLOUD    3  0  0
IRAD   VRAD   ARAD(3)  135  255  52  255  255
ICSRAD ICSTMP ICSPRS   138  141  191
ITMP   IPRS            136  191
VCSRAD VCSALB          255  255
VALBTA VTMP   VPRS     255  255  255
VTAUIC VTMPIC VPRSIC   255  255  255
NREF   NTHR   NCSREF   255  0  255
END OF IMAGE ON LINE  400
TOTAL PIXELS READ  113323

The amount and type of output may easily be modified by changing the
sample program lines 145 - 164:

C*--------------------------------------------------------------------*C
C* EXAMPLE:  PRINT SOME VALUES FOR A PIXEL                            *C
C*--------------------------------------------------------------------*C
IF ( IPOS .EQ.250 .AND. JPOS .EQ. 250) THEN
   PRINT *,'LON LAT IPOS JPOS',LON,LAT,IPOS,JPOS
   PRINT *,'LNDWTR HITOPO SHORE  ',LNDWTR,HITOPO,SHORE
   PRINT *,'DAYNIT SNOICE GLINT  ',DAYNIT,SNOICE,GLINT
   PRINT *,'MUE  MU0    PHI    ',MUE,MU0,PHI
   PRINT *,'ITHR         VTHR   CLOUD  ',ITHR,VTHR,CLOUD
   PRINT *,'IRAD         VRAD   ARAD(3)',IRAD,VRAD,ARAD
   PRINT *,'ICSRAD ICSTMP ICSPRS ',ICSRAD,ICSTMP,ICSPRS
   PRINT *,'ITMP         IPRS          ',ITMP,IPRS
   PRINT *,'VCSRAD VCSALB      ',VCSRAD,VCSALB
   PRINT *,'VALBTA VTMP VPRS   ',VALBTA,VTMP,VPRS
   PRINT *,'VTAUIC VTMPIC VPRSIC ',VTAUIC,VTMPIC,VPRSIC
   PRINT *,'NREF         NTHR   NCSREF ',NREF,NTHR,NCSREF
      END IF        
C*--------------------------------------------------------------------*C
C* END OF PIXEL LOOP                                                  *C
C*--------------------------------------------------------------------*C

Last updated: April 15, 1999    LD_008_003_001_00_00_0_19990415