[gradsusr] Grads cannot open MERRA HDF file

[Mike Bosilovich]

Thanks, I have found the ctl files for HDF particularly useful
especially for MERRA. However, I don't think that is the root of the
problem. I just created my own subset from 1979-01-01 and the HDF
opened with sdfopen, no problem. (PC Opengrads built on 2.0.a9,oga.1)

There are some other ways to debug this problem. First, have you
looked at the size of the files? The netcdf and hdf should be the same
or similar size. If not, perhaps there was a corruption in the
transfer.  Second, there should be hdf utilities that can scan the
header, or other hdf software. Do those read the file OK?  Does your
installation of grads read other HDF files OK?

When using the MERRA subsetter, the user is provided an http link
intended to be run in wget. You can post that link to this forum, then
folks interested to help can either cut/paste it to wget, or perhaps
just click the link and save the file to their local machine. So, no
need for instructions to fill out the www forms or even go the the
download site. For that matter, this is also a way for users to have a
backup point for their subset files, without mechanically duplicating
them. Of course, each user needs to balance the cost of storage versus
download time as a backup method.

So, try to redo the download from your saved link  (be sure to delete
the file that doesn't work). run the download again. If that doesn't
work, then post the link.

Mike

On Thu, Jul 5, 2012 at 2:17 AM, Jayakrishnan P.R
<prjayakrishnan at gmail.com> wrote:
> Dear Yalei,
>                I think you will have to write a ctl file for the hdf file
> with dtype hdfsds. I have tried it here with no success. You can modify the
> attached ctl file and test the case. Best of luck.
>
> DSET MERRA100.prod.assim.inst3_3d_asm_Cp.19790131.SUB.hdf
> TITLE This is only a test
> DTYPE hdfsds
> UNDEF -32768
> XDEF 36 LINEAR 60 1.25
> YDEF 24 LINEAR  0 1.25
> TDEF TIME4DIMS:DAOgrid 1 LINEAR 0Z31JUL1993 6HR
> VARS 1
> var1=>var1 1 99 var
> ENDVARS
>
> More informations are there in the section HDF-SDS in grads
>
> http://www.iges.org/grads/gadoc/gadocindex.html
>
>
> --
> Sincerely
> ***********************************************
> Jayakrishnan.P.R
> CSIR-Senior Research Fellow
> Department of Atmospheric Sciences
> Cochin University of Science and Technology (CUSAT), Cochin-682 016
> Kerala, India.
> Mob: 09895417565
>
> ***********************************************
>
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