[gradsusr] Problem in opening MODIS HDF files

James T. Potemra jimp at hawaii.edu
Sat Oct 13 22:46:36 EDT 2012


Ehsan:

I think there is a character limit on the variable name.  So, you have
a variable called "Angstrom_Exponent_Land_QA_Mean", but GrADS
is looking for "angstrom_expone".  Instead, you can map the variable
to something shorter (see http://www.iges.org/grads/gadoc/gadocindex.html),
e.g., in your ctl file:

Angstrom_Exponent_Land_QA_Mean=>AELQA_Mean      0    1,  1,  0, 0 
Surface pressure [hPa]

then open and display "aelqa_mean", or whatever you call it.

Jim

On 10/13/12 1:54 PM, Ehsan Erfani wrote:
> Hi again,
>
> I attached an hdf file with a ctl (I downloaded the data from Giovanni 
> website and I wrote the ctl). This time, the Grads can open the data, 
> but when I write the command: d Angstrom_Exponent_Land_QA_Mean, This 
> error message appears:
> Syntax Error:  Invalid Operand
>   'angstrom_exponent' not a variable or function name
>   Error ocurred at column 1
> DISPLAY error:  Invalid expression
>   Expression = angstrom_exponent_land_qa_mean
>
> But, I am sure the name of variable is true. I checked it by HDFView 
> and this is the information from HDFView:
> Angstrom_Exponent_Land_QA_Mean (720, 2)
>     32-bit floating-point,    180 x 360
>     Number of attributes = 18
>         _FillValue = -9999.0
>         QA_Useful_Flag_Bit = 0
>         Quality_Assurance_Data_Set = Quality_Assurance_Land
>         scale_factor = 1.0
>         QA_Value_Start_Bit = 1
>         add_offset = 0.0
>         long_name = Angstrom exponent (Land) for 0.47 and 0.66 
> microns: Level-2 QA Weighted Mean
>         Statistic_Type = Simple
>         units = unitless
>         QA_Byte = 0
>         Aggregation_Data_Set = None
>         valid_range = -500,5000
>         Included_Level_2_Nighttime_Data = False
>         Derived_From_Level_2_Data_Set = Angstrom_Exponent_Land
>         QA_Value_Num_Bits = 3
>         Level_2_Pixel_Values_Read_As = Real
>         structureType = Grid
>         unitsCategory = exponent
>
> Hope these help to solve the problems. I appreciate all your 
> consideration and help.
>
> Best regards,
> Ehsan
>
> On Sat, Oct 13, 2012 at 1:26 AM, Ehsan Erfani <e.erfani81 at gmail.com 
> <mailto:e.erfani81 at gmail.com>> wrote:
>
>     1- I used grads-2.0.a3.oga.1.win32_superpack (GrADS OPenNDAP).
>     Also, I tried grads-2.0.1.oga.1-win32_superpack.
>     2- Both of them are opengrads and run in windows.
>     3- First, I want to open hdf data without ctl (I have a lot of
>     data and they do not have similar variables). So, I consider using
>     sdfopen to open the files.
>
>     4- By using sdfopen, I received these error message for the above
>     grads versions, respectively:
>
>
>     "gradsdf : SDF file has no discernable X coordinate."
>
>     "gadsdf: SDF file has no discernable X coordinate.
>      To open this file with GrADS, use a descriptor file with an XDEF
>     entry."
>
>     5- I used MODIS hdf files. A typical name of the files can be
>     "MOD08_D3.A2011152.051.2011153120457.hdf". I wanted to plot 550 nm
>     AOD and deep blue AOD. These data are typical satellite data from
>     terra or aqua.
>     I do not have access to linux to provide ncdump data. Anyway, the
>     message would be very long and I write some first lines
>     (containing the dimension and grid data) from the HDF Import Tool
>     and write the full message in the end:
>     Name: MERRA200.prod.assim.tavg1_2d_lnd_Nx.20000601.hdf
>     HDFEOSVersion: HDFEOS_V2.14 StructMetadata.0: GROUP=SwathStructure
>     END_GROUP=SwathStructure GROUP=GridStructure     GROUP=GRID_1
>     GridName="EOSGRID"         XDim=540 YDim=361
>     UpperLeftPointMtrs=(-180000000.000000,90000000.000000)
>     LowerRightMtrs=(180000000.000000,-90000000.000000)
>     Projection=GCTP_GEO         GridOrigin=HDFE_GD_LL GROUP=Dimension
>     OBJECT=Dimension_1 DimensionName="TIME"                 Size=24
>     END_OBJECT=Dimension_1         END_GROUP=Dimension GROUP=DataField
>     OBJECT=DataField_1 DataFieldName="GRN" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") 3- I used sdfopen command to open them.
>
>     Final word:
>     I know that the problem can be due to the dimension, however the
>     dimension is defined in the data by XDim and YDim, Time.  I wonder
>     does anyone successfully use GrADS to open hdf files by sdfopen
>     command. Is a certain version of GrADS recommended to do this?
>
>     Thank you in advance,
>     Ehsan
>
>
>     On Fri, Oct 12, 2012 at 10:53 AM, Jennifer Adams
>     <jma at cola.iges.org <mailto:jma at cola.iges.org>> wrote:
>
>         Your post is missing the following information:
>         1. The version of GrADS you are running
>         2. What operating system you're running it on
>         3. The contents of your ctl file
>         4. The error message you get when you try to open your ctl file
>         5. More information about the grid in your MODIS file,
>         especially the output from ncdump (which is often enabled to
>         handle HDF files)
>         Nobody can help until you provide these things.
>         --Jennifer
>
>
>
>
>     Name: MERRA200.prod.assim.tavg1_2d_lnd_Nx.20000601.hdf
>     HDFEOSVersion: HDFEOS_V2.14 StructMetadata.0: GROUP=SwathStructure
>     END_GROUP=SwathStructure GROUP=GridStructure     GROUP=GRID_1
>     GridName="EOSGRID"         XDim=540 YDim=361
>     UpperLeftPointMtrs=(-180000000.000000,90000000.000000)
>     LowerRightMtrs=(180000000.000000,-90000000.000000)
>     Projection=GCTP_GEO         GridOrigin=HDFE_GD_LL GROUP=Dimension
>     OBJECT=Dimension_1 DimensionName="TIME"                 Size=24
>     END_OBJECT=Dimension_1         END_GROUP=Dimension GROUP=DataField
>     OBJECT=DataField_1 DataFieldName="GRN" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_1
>     OBJECT=DataField_2 DataFieldName="LAI" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_2
>     OBJECT=DataField_3 DataFieldName="GWETROOT" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_3
>     OBJECT=DataField_4 DataFieldName="GWETTOP" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_4
>     OBJECT=DataField_5 DataFieldName="TPSNOW" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_5
>     OBJECT=DataField_6 DataFieldName="TUNST" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_6
>     OBJECT=DataField_7 DataFieldName="TSAT" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_7
>     OBJECT=DataField_8 DataFieldName="TWLT" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_8
>     OBJECT=DataField_9 DataFieldName="PRECSNO" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_9
>     OBJECT=DataField_10 DataFieldName="PRECTOT" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_10
>     OBJECT=DataField_11 DataFieldName="SNOMAS" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_11
>     OBJECT=DataField_12 DataFieldName="SNODP" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_12
>     OBJECT=DataField_13 DataFieldName="EVPSOIL" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_13
>     OBJECT=DataField_14 DataFieldName="EVPTRNS" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_14
>     OBJECT=DataField_15 DataFieldName="EVPINTR" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_15
>     OBJECT=DataField_16 DataFieldName="EVPSBLN" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_16
>     OBJECT=DataField_17 DataFieldName="RUNOFF" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_17
>     OBJECT=DataField_18 DataFieldName="BASEFLOW" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_18
>     OBJECT=DataField_19 DataFieldName="SMLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_19
>     OBJECT=DataField_20 DataFieldName="FRUNST" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_20
>     OBJECT=DataField_21 DataFieldName="FRSAT" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_21
>     OBJECT=DataField_22 DataFieldName="FRSNO" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_22
>     OBJECT=DataField_23 DataFieldName="FRWLT" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_23
>     OBJECT=DataField_24 DataFieldName="PARDF" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_24
>     OBJECT=DataField_25 DataFieldName="PARDR" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_25
>     OBJECT=DataField_26 DataFieldName="SHLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_26
>     OBJECT=DataField_27 DataFieldName="LHLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_27
>     OBJECT=DataField_28 DataFieldName="EVLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_28
>     OBJECT=DataField_29 DataFieldName="LWLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_29
>     OBJECT=DataField_30 DataFieldName="SWLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_30
>     OBJECT=DataField_31 DataFieldName="GHLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_31
>     OBJECT=DataField_32 DataFieldName="TWLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_32
>     OBJECT=DataField_33 DataFieldName="TELAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_33
>     OBJECT=DataField_34 DataFieldName="WCHANGE" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_34
>     OBJECT=DataField_35 DataFieldName="ECHANGE" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_35
>     OBJECT=DataField_36 DataFieldName="SPLAND" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_36
>     OBJECT=DataField_37 DataFieldName="SPWATR" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_37
>     OBJECT=DataField_38 DataFieldName="SPSNOW" DataType=DFNT_FLOAT32
>     DimList=("TIME","YDim","XDim") END_OBJECT=DataField_38
>     OBJECT=DataField_39 DataFieldName="XDim" DataType=DFNT_FLOAT64
>     DimList=("XDim") END_OBJECT=DataField_39 OBJECT=DataField_40
>     DataFieldName="YDim" DataType=DFNT_FLOAT64 DimList=("YDim")
>     END_OBJECT=DataField_40 OBJECT=DataField_41 DataFieldName="Time"
>     DataType=DFNT_FLOAT64 DimList=("TIME") END_OBJECT=DataField_41
>     END_GROUP=DataField         GROUP=MergedFields
>     END_GROUP=MergedFields     END_GROUP=GRID_1
>     END_GROUP=GridStructure GROUP=PointStructure
>     END_GROUP=PointStructure END
>
>         On Oct 11, 2012, at 9:53 PM, Ehsan Erfani wrote:
>
>>         Hello,
>>
>>         I cannot open MODIS (Moderate Resolution Imaging
>>         Spectroradiometer) HDF files by grads. I receive this message
>>         when I use the sdfopen:
>>         "gradsdf : SDF file has no discernable X coordinate."
>>
>>         I tried to open by xdfopen without any success. Also, I made
>>         a ctl but again it did not help. I appreciate it if you let
>>         me know how to open hdf files by GrADS. Thank you.
>>
>>         Best regards,
>>         Ehsan _______________________________________________
>>         gradsusr mailing list
>>         gradsusr at gradsusr.org <mailto: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 <mailto:jma at cola.iges.org>
>
>
>
>
>         _______________________________________________
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>
>
>
>
>
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