[gradsusr] open HDF4 cloudsat using Grads

Jennifer M Adams jadams21 at gmu.edu
Wed Mar 29 09:26:54 EDT 2017


Malcolm,
The HDFEOS format has a lot of metadata, but not the critical piece: “Variable Name = unused”
There is no way for GrADS to handle a variable named ‘\0’ (null). Perhaps you can use the hdp dump tool to rewrite the data in another format (ascii or binary or netcdf)?
—Jennifer

On Mar 28, 2017, at 10:45 PM, Malcolm Tang <malct32 at gmail.com<mailto:malct32 at gmail.com>> wrote:

Hi,
I have downloaded HDF4 precipitation data from Cloudsat website.
Opening the hdf requires a descriptor file.

i have written a descriptor file:

dset 20150303.hdf
dtype hdfsds
title Precipitation
undef -9999 _FillValue
options yrev
xdef 360 linear -180 1.0
ydef 180 linear -89.5 1.0
zdef 1 levels 1000.0
tdef 1  linear 00:00Z31dec2006 1dy
vars 1
2C-PRECIP-COLUMN=>pr 0 y,x precipitation

endvars

Using the descriptor file, I could open the file. However, I could not display the precipitation data.

ga-> d pr
Error: Variable 2C-PRECIP-COLUMN not in HDF-SDS file
Data Request Error:  Error for variable 'pr'
  Error ocurred at column 1
DISPLAY error:  Invalid expression
  Expression = pr

using the command "hdp dumpsds 20150303.hdf", i get the following information:

File name: 20150303.hdf

File attributes:
     Attr0: Name = HDFEOSVersion
         Type = 8-bit signed char
         Count= 11
         Value = HDFEOS_V2.5
     Attr1: Name = StructMetadata.0
         Type = 8-bit signed char
         Count= 32000
         Value = GROUP=SwathStructure\012\011GROUP=SWATH_1
                         \012\011\011SwathName="2C-PRECIP-COLUMN"\012
                         \011\011GROUP=Dimension\012\011\011\011OB
                         JECT=Dimension_1\012\011\011\011\011Dimen
                         sionName="nray"\012\011\011\011\011Size=2
                         0677\012\011\011\011END_OBJECT=Dimension_
                         1\012\011\011\011OBJECT=Dimension_2\012\011
                         \011\011\011DimensionName="scalar"\012\011
                         \011\011\011Size=1\012\011\011\011END_OBJ
                         ECT=Dimension_2\012\011\011\011OBJECT=Dim
                         ension_3\012\011\011\011\011DimensionName
                         ="x"\012\011\011\011\011Size=1\012\011\011
                         \011END_OBJECT=Dimension_3\012\011\011\011
                         OBJECT=Dimension_4\012\011\011\011\011Dim
                         ensionName="y"\012\011\011\011\011Size=1\012
                         \011\011\011END_OBJECT=Dimension_4\012\011
                         \011END_GROUP=Dimension\012\011\011GROUP=
                         DimensionMap\012\011\011END_GROUP=Dimensi
                         onMap\012\011\011GROUP=IndexDimensionMap\012
                         \011\011END_GROUP=IndexDimensionMap\012\011
                         \011GROUP=GeoField\012\011\011\011OBJECT=
                         GeoField_1\012\011\011\011\011GeoFieldNam
                         e="Profile_time"\012\011\011\011\011DataT
                         ype=DFNT_FLOAT32\012\011\011\011\011DimLi
                         st=("nray")\012\011\011\011END_OBJECT=Geo
                         Field_1\012\011\011\011OBJECT=GeoField_2\012
                         \011\011\011\011GeoFieldName="UTC_start"\012
                         \011\011\011\011DataType=DFNT_FLOAT32\012
                         \011\011\011\011DimList=("scalar")\012\011
                         \011\011END_OBJECT=GeoField_2\012\011\011
                         \011OBJECT=GeoField_3\012\011\011\011\011
                         GeoFieldName="TAI_start"\012\011\011\011\011
                         DataType=DFNT_FLOAT64\012\011\011\011\011
                         DimList=("scalar")\012\011\011\011END_OBJ
                         ECT=GeoField_3\012\011\011\011OBJECT=GeoF
                         ield_4\012\011\011\011\011GeoFieldName="L
                         atitude"\012\011\011\011\011DataType=DFNT
                         _FLOAT32\012\011\011\011\011DimList=("nra
                         y")\012\011\011\011END_OBJECT=GeoField_4\012
                         \011\011\011OBJECT=GeoField_5\012\011\011
                         \011\011GeoFieldName="Longitude"\012\011\011
                         \011\011DataType=DFNT_FLOAT32\012\011\011
                         \011\011DimList=("nray")\012\011\011\011E
                         ND_OBJECT=GeoField_5\012\011\011\011OBJEC
                         T=GeoField_6\012\011\011\011\011GeoFieldN
                         ame="DEM_elevation"\012\011\011\011\011Da
                         taType=DFNT_INT16\012\011\011\011\011DimL
                         ist=("nray")\012\011\011\011END_OBJECT=Ge
                         oField_6\012\011\011END_GROUP=GeoField\012
                         \011\011GROUP=DataField\012\011\011\011OB
                         JECT=DataField_1\012\011\011\011\011DataF
                         ieldName="Data_quality"\012\011\011\011\011
                         DataType=DFNT_UINT8\012\011\011\011\011Di
                         mList=("nray")\012\011\011\011END_OBJECT=
                         DataField_1\012\011\011\011OBJECT=DataFie
                         ld_2\012\011\011\011\011DataFieldName="Da
                         ta_status"\012\011\011\011\011DataType=DF
                         NT_UINT8\012\011\011\011\011DimList=("nra
                         y")\012\011\011\011END_OBJECT=DataField_2
                         \012\011\011\011OBJECT=DataField_3\012\011
                         \011\011\011DataFieldName="Data_targetID"
                         \012\011\011\011\011DataType=DFNT_UINT8\012
                         \011\011\011\011DimList=("nray")\012\011\011
                         \011END_OBJECT=DataField_3\012\011\011\011
                         OBJECT=DataField_4\012\011\011\011\011Dat
                         aFieldName="Precip_flag"\012\011\011\011\011
                         DataType=DFNT_INT8\012\011\011\011\011Dim
                         List=("nray")\012\011\011\011END_OBJECT=D
                         ataField_4\012\011\011\011OBJECT=DataFiel
                         d_5\012\011\011\011\011DataFieldName="Sta
                         tus_flag"\012\011\011\011\011DataType=DFN
                         T_INT8\012\011\011\011\011DimList=("nray"
                         )\012\011\011\011END_OBJECT=DataField_5\012
                         \011\011\011OBJECT=DataField_6\012\011\011
                         \011\011DataFieldName="Conv_strat_flag"\012
                         \011\011\011\011DataType=DFNT_INT16\012\011
                         \011\011\011DimList=("nray")\012\011\011\011
                         END_OBJECT=DataField_6\012\011\011\011OBJ
                         ECT=DataField_7\012\011\011\011\011DataFi
                         eldName="Precip_rate"\012\011\011\011\011
                         DataType=DFNT_FLOAT32\012\011\011\011\011
                         DimList=("nray")\012\011\011\011END_OBJEC
                         T=DataField_7\012\011\011\011OBJECT=DataF
                         ield_8\012\011\011\011\011DataFieldName="
                         Precip_rate_min"\012\011\011\011\011DataT
                         ype=DFNT_FLOAT32\012\011\011\011\011DimLi
                         st=("nray")\012\011\011\011END_OBJECT=Dat
                         aField_8\012\011\011\011OBJECT=DataField_
                         9\012\011\011\011\011DataFieldName="Preci
                         p_rate_max"\012\011\011\011\011DataType=D
                         FNT_FLOAT32\012\011\011\011\011DimList=("
                         nray")\012\011\011\011END_OBJECT=DataFiel
                         d_9\012\011\011\011OBJECT=DataField_10\012
                         \011\011\011\011DataFieldName="Precip_rat
                         e_no_ms"\012\011\011\011\011DataType=DFNT
                         _FLOAT32\012\011\011\011\011DimList=("nra
                         y")\012\011\011\011END_OBJECT=DataField_1
                         0\012\011\011\011OBJECT=DataField_11\012\011
                         \011\011\011DataFieldName="PIA_hydrometeo
                         r"\012\011\011\011\011DataType=DFNT_FLOAT
                         32\012\011\011\011\011DimList=("nray")\012
                         \011\011\011END_OBJECT=DataField_11\012\011
                         \011\011OBJECT=DataField_12\012\011\011\011
                         \011DataFieldName="PIA_near_surface"\012\011
                         \011\011\011DataType=DFNT_FLOAT32\012\011
                         \011\011\011DimList=("nray")\012\011\011\011
                         END_OBJECT=DataField_12\012\011\011\011OB
                         JECT=DataField_13\012\011\011\011\011Data
                         FieldName="PIA_uncertainty"\012\011\011\011
                         \011DataType=DFNT_FLOAT32\012\011\011\011
                         \011DimList=("nray")\012\011\011\011END_O
                         BJECT=DataField_13\012\011\011\011OBJECT=
                         DataField_14\012\011\011\011\011DataField
                         Name="Sigma_zero"\012\011\011\011\011Data
                         Type=DFNT_FLOAT32\012\011\011\011\011DimL
                         ist=("nray")\012\011\011\011END_OBJECT=Da
                         taField_14\012\011\011\011OBJECT=DataFiel
                         d_15\012\011\011\011\011DataFieldName="Ne
                         ar_surface_reflectivity"\012\011\011\011\011
                         DataType=DFNT_FLOAT32\012\011\011\011\011
                         DimList=("nray")\012\011\011\011END_OBJEC
                         T=DataField_15\012\011\011\011OBJECT=Data
                         Field_16\012\011\011\011\011DataFieldName
                         ="Frozen_precip_height"\012\011\011\011\011
                         DataType=DFNT_FLOAT32\012\011\011\011\011
                         DimList=("nray")\012\011\011\011END_OBJEC
                         T=DataField_16\012\011\011\011OBJECT=Data
                         Field_17\012\011\011\011\011DataFieldName
                         ="Rain_top_height"\012\011\011\011\011Dat
                         aType=DFNT_FLOAT32\012\011\011\011\011Dim
                         List=("nray")\012\011\011\011END_OBJECT=D
                         ataField_17\012\011\011\011OBJECT=DataFie
                         ld_18\012\011\011\011\011DataFieldName="M
                         elted_fraction"\012\011\011\011\011DataTy
                         pe=DFNT_FLOAT32\012\011\011\011\011DimLis
                         t=("nray")\012\011\011\011END_OBJECT=Data
                         Field_18\012\011\011\011OBJECT=DataField_
                         19\012\011\011\011\011DataFieldName="Lowe
                         st_sig_layer_top"\012\011\011\011\011Data
                         Type=DFNT_FLOAT32\012\011\011\011\011DimL
                         ist=("nray")\012\011\011\011END_OBJECT=Da
                         taField_19\012\011\011\011OBJECT=DataFiel
                         d_20\012\011\011\011\011DataFieldName="Hi
                         ghest_sig_layer_top"\012\011\011\011\011D
                         ataType=DFNT_FLOAT32\012\011\011\011\011D
                         imList=("nray")\012\011\011\011END_OBJECT
                         =DataField_20\012\011\011\011OBJECT=DataF
                         ield_21\012\011\011\011\011DataFieldName=
                         "Cloud_flag"\012\011\011\011\011DataType=
                         DFNT_INT8\012\011\011\011\011DimList=("nr
                         ay")\012\011\011\011END_OBJECT=DataField_
                         21\012\011\011\011OBJECT=DataField_22\012
                         \011\011\011\011DataFieldName="Surface_ty
                         pe"\012\011\011\011\011DataType=DFNT_INT8
                         \012\011\011\011\011DimList=("nray")\012\011
                         \011\011END_OBJECT=DataField_22\012\011\011
                         \011OBJECT=DataField_23\012\011\011\011\011
                         DataFieldName="Freezing_level"\012\011\011
                         \011\011DataType=DFNT_FLOAT32\012\011\011
                         \011\011DimList=("nray")\012\011\011\011E
                         ND_OBJECT=DataField_23\012\011\011\011OBJ
                         ECT=DataField_24\012\011\011\011\011DataF
                         ieldName="SST"\012\011\011\011\011DataTyp
                         e=DFNT_FLOAT32\012\011\011\011\011DimList
                         =("nray")\012\011\011\011END_OBJECT=DataF
                         ield_24\012\011\011\011OBJECT=DataField_2
                         5\012\011\011\011\011DataFieldName="Surfa
                         ce_wind"\012\011\011\011\011DataType=DFNT
                         _FLOAT32\012\011\011\011\011DimList=("nra
                         y")\012\011\011\011END_OBJECT=DataField_2
                         5\012\011\011\011OBJECT=DataField_26\012\011
                         \011\011\011DataFieldName="RLWP"\012\011\011
                         \011\011DataType=DFNT_FLOAT32\012\011\011
                         \011\011DimList=("nray")\012\011\011\011E
                         ND_OBJECT=DataField_26\012\011\011\011OBJ
                         ECT=DataField_27\012\011\011\011\011DataF
                         ieldName="CLWP"\012\011\011\011\011DataTy
                         pe=DFNT_FLOAT32\012\011\011\011\011DimLis
                         t=("nray")\012\011\011\011END_OBJECT=Data
                         Field_27\012\011\011\011OBJECT=DataField_
                         28\012\011\011\011\011DataFieldName="Diag
                         nostic_retrieval_info"\012\011\011\011\011
                         DataType=DFNT_INT8\012\011\011\011\011Dim
                         List=("nray")\012\011\011\011END_OBJECT=D
                         ataField_28\012\011\011\011OBJECT=DataFie
                         ld_29\012\011\011\011\011DataFieldName="D
                         iagnostic_retrieval_type"\012\011\011\011
                         \011DataType=DFNT_INT8\012\011\011\011\011
                         DimList=("nray")\012\011\011\011END_OBJEC
                         T=DataField_29\012\011\011\011OBJECT=Data
                         Field_30\012\011\011\011\011DataFieldName
                         ="Diagnostic_SRT"\012\011\011\011\011Data
                         Type=DFNT_INT8\012\011\011\011\011DimList
                         =("nray")\012\011\011\011END_OBJECT=DataF
                         ield_30\012\011\011\011OBJECT=DataField_3
                         1\012\011\011\011\011DataFieldName="unuse
                         d"\012\011\011\011\011DataType=DFNT_INT8\012
                         \011\011\011\011DimList=("y","x")\012\011
                         \011\011\011CompressionType=HDFE_COMP_DEF
                         LATE\012\011\011\011\011DeflateLevel=1\012
                         \011\011\011END_OBJECT=DataField_31\012\011
                         \011END_GROUP=DataField\012\011\011GROUP=
                         MergedFields\012\011\011END_GROUP=MergedF
                         ields\012\011END_GROUP=SWATH_1\012END_GRO
                         UP=SwathStructure\012GROUP=GridStructure\012
                         END_GROUP=GridStructure\012GROUP=PointStr
                         ucture\012END_GROUP=PointStructure\012END
                         \012\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000
                         \000\000\000\000\000\000\000\000\000\000\000


Variable Name = unused
     Index = 0
     Type= 8-bit signed integer
     Ref. = 43
     Compression method = DEFLATE
         Deflate level = 1
     Compression ratio (original:compressed) = 0.11:1
     Rank = 2
     Number of attributes = 1
     Dim0: Name=y:2C-PRECIP-COLUMN
         Size = 1
         Scale Type = number-type not set
         Number of attributes = 0
     Dim1: Name=x:2C-PRECIP-COLUMN
         Size = 1
         Scale Type = number-type not set
         Number of attributes = 0
     Attr0: Name = _FillValue
         Type = 8-bit signed integer
         Count= 1
         Value = 0
     Data :
                0

Any tips on what I've done wrong here?
Thank you so much for your help!

Regards,
Malcolm
_______________________________________________
gradsusr mailing list
gradsusr at gradsusr.org<mailto:gradsusr at gradsusr.org>
http://gradsusr.org/mailman/listinfo/gradsusr

--
Jennifer Miletta Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
George Mason University



-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20170329/8359d869/attachment-0001.html 


More information about the gradsusr mailing list