[gradsusr] fwrite gridding issue

Thu May 10 14:03:09 EDT 2012

The file is the correct size.  144*73*48212*4=2027218176

-rw-r--r-- 1 ter businger 2027218176 May  9 15:57 chi_33yr.dat

My computer crashes if I try to do all 48212, so I had to break it up in 68
separate files each with 709 time steps.  So:
      PARAMETER (nt=709) !Number of time steps in each file
      PARAMETER (nrec=709) !Number of records in each file
      PARAMETER (files=68) !Number of input files
The FORTRAN program reads in all of the files and stores the data in one
variable chi, then it goes written out to the file chi_33yr.dat.

My FORTRAN program also calculates a 33 year 6-hourly mean, but the
variable chi isn't affected by that and that is written to a separate file
which is also having the same problem.

-Tom

On Thu, May 10, 2012 at 7:51 AM, Jennifer Adams <jma at cola.iges.org> wrote:

> I'm no fortran expert, but I think "direct" means the 4-byte headers and
> footers for each record are not written, so you should remove 'options
> sequential'. According to your descriptor, your data file (chi_33yr.dat)
> should be 144*73*48212*4 bytes large. Is it? What is 'files'?
> --Jennifer
>
>
> On May 10, 2012, at 1:44 PM, Thomas Robinson wrote:
>
> Here is my code that opens and writes out the data:
>
>       open (unit=291,file="chi_33yr.dat", access="direct",
>      &      status="unknown",recl=4*nx*ny*nt*files)
>           write (291, rec=1) chi
>
> The variable chi has dimensions nx,ny,nt*files .
>
> I added options sequential to the descriptor file and the same thing is
> happening.  Here is my descriptor file:
>
> dset ^chi_33yr.dat
> title Velocity Potential
> options sequential
> undef 9.999e+20
> xdef 144 linear 0 2.5
> ydef 73 linear -90 2.5
> zdef 1 levels 200
> tdef 48212 linear 00Z01JAN1979 360mn
> vars 1
> chi 0 x,y,t 1 ** velocity potential
> endvars
>
> All of your input is very much appreciated.
>
> -Tom
>
>
> On Fri, May 11, 2012 at 3:16 AM, Jennifer Adams <jma at cola.iges.org> wrote:
>
>> Tom, Did you include 'options sequential' in your descriptor file for
>> your new binary file? --Jennifer
>>
>>
>> On May 10, 2012, at 8:49 AM, Raghu Reddy wrote:
>>
>> I am not a grads user, just responding to the FORTRAN/C issue.****
>> ** **
>> If you do a normal sequential FORTRAN write, it writes an end-of-record
>> marker at the beginning **and** at the end of **every** write.  Since
>> you mentioned that the data is skewed, I assume you wrote all the 48,000
>> values with one write statement, and that would result in one EOR marker at
>> the beginning and one EOR marker at the end.****
>> ** **
>> If you don’t want these EOR markers you could write the file out as
>> direct access files in Fortran.****
>> ** **
>> Hope this helps.****
>> ** **
>> Thanks,****
>> ** **
>> --Raghu****
>> ** **
>> ** **
>> ** **
>> *From:* gradsusr-bounces at gradsusr.org [mailto:
>> gradsusr-bounces at gradsusr.org] *On Behalf Of *Thomas Robinson
>> *Sent:* Wednesday, May 09, 2012 11:36 PM
>> *To:* GrADS Users Forum
>> *Subject:* [gradsusr] fwrite gridding issue****
>> ** **
>>
>> Aloha,
>>
>> I used fwrite to write out to a binary file in order to create a large
>> file with about 48000 time steps for global data (because I am crazy).  I
>> noticed that when I use fortran to create a new data file that has all
>> 48000, it doesn't match with what the original data plotted, instead it
>> seems skewed.  No manipulations were done to the data, it was just read it
>> all in and write it out.  When I tried to loop the data, I further noticed
>> that the northern border looped around the south and then moved upwards
>> back to the north.  It just keeps looping around and it's odd because the
>> top boundary of the map isn't continuous with the bottom boundary (unlike
>> the side boundaries which are continuous).  Anyways, I am wondering why
>> this happened and what I can do to make it work out correctly.
>>
>> Here is my fwrite code.  it is the first time step, nt is the last time
>> step, chi is the velocity potential that was calculated using 'define chi =
>> fish_chi(UGRDprs,VGRDprs)' :
>> *# set up global domain
>> 'set lev 200 '
>> 'set lat -90 90'
>> 'set lon 0 360'
>> *#**************************************************************
>> say 'write data out to binary file called CHI.200hPa'filenum'.dat'
>> 'set fwrite -le -sq -cl CHI_200hPa_'filenum'.dat'
>> 'set gxout fwrite'
>> while (it <= nt)
>>      'set t 'it
>>      'display chi'
>> it=it+1
>> endwhile
>> 'disable fwrite'
>>
>> Mahalo for your help!
>> -Tom
>>
>> --
>> Tom Robinson
>> President Graduate Student Organization
>> Student Caucus Representative for the Graduate Student Organization
>> Graduate Student - Department of Meteorology
>> 732-718-2323****
>> _______________________________________________
>>
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>>  --
>> Jennifer M. Adams
>> IGES/COLA
>> 4041 Powder Mill Road, Suite 302
>> Calverton, MD 20705
>> jma at cola.iges.org
>>
>>
>>
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
>
> --
> Tom Robinson
> President Graduate Student Organization
> Student Caucus Representative for the Graduate Student Organization
> Graduate Student - Department of Meteorology
> 732-718-2323
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>
> --
> Jennifer M. Adams
> IGES/COLA
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705
> jma at cola.iges.org
>
>
>
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>

-- 
Tom Robinson
President Graduate Student Organization
Student Caucus Representative for the Graduate Student Organization
Graduate Student - Department of Meteorology
732-718-2323
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