[gradsusr] GrADS Control File for Array with Spectral Band Dimension

[Jennifer Adams]

First of all, thank you for providing all the information and data I needed to reproduce the error! The failure of method 1 (using array indices in the units field of the variable declaration instead of x,y,z,t,e) is indeed a bug that is unique to the hdf5 data type. The critical bit of information in the error message from the HDF5 library was this: "src and dest data spaces have different sizes." In method 1, the variables are described to GrADS as being only 2-dimensional (i.e., not Z-varying) even though they really have 3 varying dimensions, and the library trips on this deception. The netcdf library is not as fussy. I will put a fix in version 2.1, but for now you will have to use method 2. 
--Jennifer


On Sep 19, 2013, at 3:29 PM, James E. Johnson wrote:

> I'm using grads-2.0.2-bin-CentOS5.8-x86_64.tar.gz
> 
> I have an HDF-EOS5 file with some data arrays that are 3 dimensional, with the 
> third dimension representing wavelength/spectral band. I created a control 
> file for this data following the description at 
> http://www.iges.org/grads/gadoc/gadocindex.html (section VAR subsection 
> units). It says there are two ways to implement this, first with an array 
> index in the units dimension list, the second with dimension values specified 
> in the Z axis. The second method works, however the first method keeps giving 
> me errors:
> 
> HDF5-DIAG: Error detected in HDF5 (1.8.7) thread 0:
>  #000: H5Dio.c line 174 in H5Dread(): can't read data
>    major: Dataset
>    minor: Read failed
>  #001: H5Dio.c line 348 in H5D_read(): src and dest data spaces have 
> different sizes
>    major: Invalid arguments to routine
>    minor: Bad value
> H5Dread failed for short data
> Data Request Error:  Error for variable 'aaod342'
>  Error ocurred at column 1
> DISPLAY error:  Invalid expression
>  Expression = aaod342
> 
> 
> 
> The sample data file is:
> ftp://acdisc.gsfc.nasa.gov/data/s4pa/Aura_OMI_Level3/OMAEROe.003/2013/OMI-
> Aura_L3-OMAEROe_2013m0601_v003-2013m0603t015851.he5
> 
> 
> First method (array index) control file:
> DSET OMI-Aura_L3-OMAEROe_2013m0601_v003-2013m0603t015851.he5
> DTYPE hdf5_grid
> TITLE OMI/Aura Multi-wavelength Aerosol Optical Depth and Single Scattering 
> Albedo Daily L3 Global 0.25x0.25 deg Lat/Lon Grid for 1 June 2013
> UNDEF -32767 _FillValue
> XDEF 1440 linear -180 0.25
> YDEF 720 linear -90 0.25
> ZDEF 1 levels 1
> TDEF 1 linear 1jun2013 1dy
> VARS 5
> /HDFEOS/GRIDS/ColumnAmountAerosol/Data~Fields/AbsorbingAerosolOpticalThicknessMW=>aaod342  
> 0  0,y,x  Absorbing Aerosol Optical Thickness at 342.5 nm
> /HDFEOS/GRIDS/ColumnAmountAerosol/Data~Fields/AbsorbingAerosolOpticalThicknessMW=>aaod388  
> 0  1,y,x  Absorbing Aerosol Optical Thickness at 388.0 nm
> /HDFEOS/GRIDS/ColumnAmountAerosol/Data~Fields/AbsorbingAerosolOpticalThicknessMW=>aaod442  
> 0  2,y,x  Absorbing Aerosol Optical Thickness at 442.0 nm
> /HDFEOS/GRIDS/ColumnAmountAerosol/Data~Fields/AbsorbingAerosolOpticalThicknessMW=>aaod463  
> 0  3,y,x  Absorbing Aerosol Optical Thickness at 463.0 nm
> /HDFEOS/GRIDS/ColumnAmountAerosol/Data~Fields/AbsorbingAerosolOpticalThicknessMW=>aaod483  
> 0  4,y,x  Absorbing Aerosol Optical Thickness at 483.5 nm
> ENDVARS
> 
> 
> Second method (Z dimension) control file:
> DSET OMI-Aura_L3-OMAEROe_2013m0601_v003-2013m0603t015851.he5
> DTYPE hdf5_grid
> TITLE OMI/Aura Multi-wavelength Aerosol Optical Depth and Single Scattering 
> Albedo Daily L3 Global 0.25x0.25 deg Lat/Lon Grid for 1 June 2013
> UNDEF -32767 _FillValue
> XDEF 1440 linear -180 0.25
> YDEF 720 linear -90 0.25
> ZDEF 5 levels 342.5 388.0 442.0 463.0 483.5
> TDEF 1 linear 1jun2013 1dy
> VARS 1
> /HDFEOS/GRIDS/ColumnAmountAerosol/Data~Fields/AbsorbingAerosolOpticalThicknessMW=>aaod  
> 5  z,y,x  Absorbing Aerosol Optical Thickness
> ENDVARS
> 
> 
> How do I get method 1 (array index) to work? Is there something wrong with 
> ZDEF? Or is this a GrADS bug?
> 
> ------------------------------------------------------------------------------
> | James E. Johnson                   | address:                              |
> | ADNET Systems, Inc.                |  NASA Goddard Space Flight Center     |
> | e-mail: james.johnson at nasa.gov     |  Data and Information Services Center |
> | phone:  301-614-5121               |  Code 610.2, Bldg 32, Room S130G      |
> | fax:    301-614-5268               |  Greenbelt, MD  20771                 |
> ------------------------------------------------------------------------------
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--
Jennifer M. Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
111 Research Hall, Mail Stop 2B3
George Mason University
4400 University Drive
Fairfax, VA 22030 





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