[gradsusr] Grads cannot open MERRA HDF file
You, Yalei
yy08 at fsu.edu
Thu Jul 5 12:23:11 EDT 2012
Thank you all for the reply.
1. I tried the ctl file, it won't work either. Here is the information:
Scanning description file: test.ctl
Open Error: Data file type invalid
--> The invalid description file record is:
--> DTYPE hdfsds
The data file was not opened.
2. both NETCDF and HDF have similar size, though not exactly the same. (one is 1.3M, the other 1.4M).
3. I can use "hdp" command under Ubuntu 11.01 to dump the data, which looks correct (see below).
4. Here is the link of the subdata (I tried the "copy link location", and then use "wget",it won't work).
http://goldsmr3.sci.gsfc.nasa.gov/cgi-bin/dpool/HTTP_DpFileDownloadMERRA.pl?DATASET=MERRA_DP&FCP_DIR=/ftp/private/tmp/&APPLICATION=SUBSET_LATS4D&FILTER=SUBSET_LATS4D&SUB_LONMIN=-180&SUB_LONMAX=180&SUB_LATMAX=90&SUB_LATMIN=-90&OUTPUT_FORMAT=HDF&LOOKUPID_List=MAI3CPASM&STARTYR=1979&STARTMON=01&STARTDAY=01&ENDYR=1979&ENDMON=01&ENDDAY=01&variable=ps&
*******************************
hdp dumpsds -h MERRA100.prod.assim.inst3_3d_asm_Cp.19790101.SUB.hdf
File name: MERRA100.prod.assim.inst3_3d_asm_Cp.19790101.SUB.hdf
File attributes:
Attr0: Name = Conventions
Type = 8-bit signed char
Count= 7
Value = COARDS\000
Attr1: Name = calendar
Type = 8-bit signed char
Count= 9
Value = standard\000
Attr2: Name = comments
Type = 8-bit signed char
Count= 98
Value = file created by grads using lats4d availa
ble from http://dao.gsfc.nasa.gov/softwar
e/grads/lats4d/\000
Attr3: Name = model
Type = 8-bit signed char
Count= 9
Value = geos/das\000
Attr4: Name = center
Type = 8-bit signed char
Count= 5
Value = gsfc\000
Variable Name = time
Index = 0
Type= 64-bit floating point
Ref. = 2
Compression method = NONE
Rank = 1
Number of attributes = 1
Dim0: Name=time
Size = UNLIMITED (currently 8)
Scale Type = number-type not set
Number of attributes = 0
Attr0: Name = units
Type = 8-bit signed char
Count= 23
Value = hours since 1979-1-1 0\000
Variable Name = longitude
Index = 1
Type= 64-bit floating point
Ref. = 3
Compression method = NONE
Rank = 1
Number of attributes = 2
Dim0: Name=longitude
Size = 288
Scale Type = number-type not set
Number of attributes = 0
Attr0: Name = units
Type = 8-bit signed char
Count= 13
Value = degrees_east\000
Attr1: Name = long_name
Type = 8-bit signed char
Count= 10
Value = Longitude\000
Variable Name = latitude
Index = 2
Type= 64-bit floating point
Ref. = 4
Compression method = NONE
Rank = 1
Number of attributes = 2
Dim0: Name=latitude
Size = 144
Scale Type = number-type not set
Number of attributes = 0
Attr0: Name = units
Type = 8-bit signed char
Count= 14
Value = degrees_north\000
Attr1: Name = long_name
Type = 8-bit signed char
Count= 9
Value = Latitude\000
Variable Name = ps
Index = 3
Type= 32-bit floating point
Ref. = 5
Compression method = NONE
Rank = 3
Number of attributes = 8
Dim0: Name=time
Size = UNLIMITED (currently 8)
Scale Type = number-type not set
Number of attributes = 0
Dim1: Name=latitude
Size = 144
Scale Type = number-type not set
Number of attributes = 0
Dim2: Name=longitude
Size = 288
Scale Type = number-type not set
Number of attributes = 0
Attr0: Name = comments
Type = 8-bit signed char
Count= 26
Value = Unknown1 variable comment\000
Attr1: Name = long_name
Type = 8-bit signed char
Count= 17
Value = Surface pressure\000
Attr2: Name = units
Type = 8-bit signed char
Count= 1
Value = \000
Attr3: Name = grid_name
Type = 8-bit signed char
Count= 7
Value = grid-1\000
Attr4: Name = grid_type
Type = 8-bit signed char
Count= 7
Value = linear\000
Attr5: Name = level_description
Type = 8-bit signed char
Count= 14
Value = Earth surface\000
Attr6: Name = time_statistic
Type = 8-bit signed char
Count= 14
Value = instantaneous\000
Attr7: Name = missing_value
Type = 32-bit floating point
Count= 1
Value = 999999986991104.000000
*******************************
________________________________________
From: gradsusr-bounces at gradsusr.org [gradsusr-bounces at gradsusr.org] on behalf of Mike Bosilovich [mike.bosilovich at gmail.com]
Sent: Thursday, July 05, 2012 9:12 AM
To: GrADS Users Forum
Subject: Re: [gradsusr] Grads cannot open MERRA HDF file
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
>
> ***********************************************
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
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