How can I use fortran to read a Grads binary data file

[Ming Yang]

Hi,
   Thank you for your help. I still cannot figure out how to read it. Here
is the descriptor file

DSET ^topo-ice5g.t21.bin
UNDEF -9.99e+33
options byteswapped
XDEF 64 LINEAR 0  5.6250
YDEF 32 LEVELS
  -85.761 -80.269 -74.745 -69.213
  -63.679 -58.143 -52.607 -47.070
  -41.532 -35.995 -30.458 -24.920
  -19.382 -13.844  -8.307  -2.769
    2.769   8.307  13.844  19.382
   24.920  30.458  35.995  41.532
   47.070  52.607  58.143  63.679
   69.213  74.745  80.269  85.761
ZDEF 1  LINEAR  1  1
TDEF 1  LINEAR  JAN1960 1MO
VARS 1
TOPO   1  99     Ice
ENDVARS

    And here is my fortran program

        program readbin
        integer   nlat,nlon,irec
        parameter (nlon=64, nlat=32)
        real*4 berg(nlat,nlon)

        OPEN(17,file='topo-ice5g.t21.bin',
     &STATUS='UNKNOWN',
     &FORM='UNFORMATTED',ACCESS='DIRECT', RECL=64*32)


         irec=1
         do i=1,nlat
         do j=1,nlon

         read(17,REC=irec) berg(i,j)
         irec=irec+1
         write(*,*) berg(i,j)

         enddo
         enddo

         end


       Here is what I got after run this fortran program

 -2.8802414E-11
 3.4926203E-10
 3.3586933E-22
 -1.3897608E-11

 ******  FORTRAN RUN-TIME SYSTEM  ******
 Error 1066:  record not in file
 Location:  the READ statement at line 15 of "readbin.f"
 Unit:  17
 File:  topo-ice5g.t21.bin
Abort

     The print out number is definetely wrong according the display of the
data in Grads. But I don't know how to fix it.


Best,
Ming


On Thu, 15 Sep 2005, [ISO-8859-1] Heiner Körnich wrote:

> Hi Ming,
>
> GrADS is using standard binary data. Depending on your option in .ctl,
> you read it with direct access for no option and sequential acces for
> "sequential" option. do you mean sequential with stream?
> Details to fortran are here:
> http://www.geocities.com/Athens/Olympus/5564/prof77.htm
>
> Cheers,
> Heiner
>
> Ming Yang wrote:
>
> > Hi, guys
> >     I have a Grads binary file and I want to use a fortran program to
> > read it
> > and write to an ASCII file. Do you know how can I do that. I know the
> > binary
> > file is a "stream" file and I am supposed to use direct access to read
> > it,
> > right? Thank you for your attention.
> >
> > Best,
> > Ming
> >
> > Ming Yang
> > Department of Geological Sciences
> > University of North Carolina at Chapel Hill
> > myang at email.unc.edu
> > 919-843-5846
> >
> >
>
> --
> Heiner Körnich
> Dept. of Meteorology                    Tel:    +46 8 164333
> Stockholms University
> S-106 91 Stockholm, Sweden              Email:  heiner at misu.su.se
>