HDF Scientific Data Set (SDS) Information Utility Introduction This readme file contains information about the HDF SDS Information Utility developed to provide information and indexes for all SDS's contained within an HDF data file. This Readme file includes the following sections: Section 1.0 - Description of Utility Section 2.0 - Implementing Utility and Sample Output If there are questions about using the POAM3 sample read software, please contact the Langley User and Data Services (UDS) office at: Atmospheric Science Data Center Users and Data Services Office Mail Stop 157D NASA Langley Research Center Hampton, Virginia 23681-2199 U.S.A. E-mail: support-asdc@earthdata.nasa.gov Phone: (757)864-8656 FAX: (757)864-8807 URL: http://eosweb.larc.nasa.gov 1.0 Description of Utility An Interactive Data Language Virtual Machine (IDL VM) utility is provided for generating an ASCII file of SDS information contained within HDF files. The IDL VM utility is "hdf_sds_info.sav". Please refer any questions regarding this utility to the Langley ASDC User and Data Services Office. The hdf_sds_info.sav runs using IDL VM. The IDL VM is a free runtime version of IDL available from Exelis Visual Information Solutions at http://www.exelisvis.com/Downloads/ProductDownloads.aspx. This utility has been tested with IDL 6.2 Virtual Machine. As written, the utility gathers information about the SDS's and writes to an ASCII formatted output. The output filename is generated by using the input filename and adding the extension '.out'. An information dialog box will display informing the user of the following: "Select an HDF file to generate an ASCII text output file containing information and attributes for all Science Data Sets (SDSs) contained within the HDF file." Click "OK" to proceed to the file selection GUI. Upon selecting a file, the program will proceed to completion with a final window informing the user of the location and name of the genatered ASCII formatted output file. 2.0 Implementing Utility and Sample Output Download the IDL VM from http://www.ittvis.com/Downloads/ProductDownloads.aspx and install. Start IDL VM. Select the hdf_sds_info.sav file. Choose the hdf file of interest. The utility assumes that the hdf files are on the same system as IDL VM. Write permission is needed for the directory where the data are located. At completion, an output file will contain information and SDS index numbers of all SDSs contained within the selected HDF file. The output filename is generated by using the input filename and adding the extension '.out'. Example: Obtain all SDS information contained in file CER_SRBAVG1_Terra-FM1-MODIS_Edition2C_013023.200007. Sample output file, "CER_SRBAVG1_Terra-FM1-MODIS_Edition2C_013023.200007.out", of IDL VM HDF SDS Information Utility: *****BEGINNING OF HDF_INFORMATION***** ================================================================================ FILENAME : C:\CER_SRBAVG1_Terra-FM1-MODIS_Edition2C_013023.200007 ================================================================================ # of free palettes = 0 ================================================================================ # of file file ids = 0 ================================================================================ # of file descriptions = 0 # of MFSD = 314 -------------------------------------------------------------------------------- Information about MFHDF DataSets -------------------------------------------------------------------------------- SDS# SDS Name ---- ---------------------------------- 0 Region Number Data Type => FLOAT DFNT_FLOAT32 Dimensions => 2 [ 360, 180] Units => unitless Attribute => 1 _FillValue = 3.402823E+038 Attribute => 2 long_name = 1.0 Degree Regional Monthly Hourly Region parameters Attribute => 3 units = unitless Attribute => 4 valid_range = 1.0000000 64800.0000000 ______________________________________________________________________ 1 Colatitude Data Type => FLOAT DFNT_FLOAT32 Dimensions => 2 [ 360, 180] Units => Degrees Attribute => 1 _FillValue = 3.402823E+038 Attribute => 2 long_name = 1.0 Degree Regional Monthly Hourly Region parameters Attribute => 3 units = Degrees ______________________________________________________________________ 2 Longitude Data Type => FLOAT DFNT_FLOAT32 Dimensions => 2 [ 360, 180] Units => Degrees Attribute => 1 _FillValue = 3.402823E+038 Attribute => 2 long_name = 1.0 Degree Regional Monthly Hourly Region parameters Attribute => 3 units = Degrees ______________________________________________________________________ ... ... ______________________________________________________________________ 312 LW Surface Emissivity Data Type => FLOAT DFNT_FLOAT32 Dimensions => 3 [ 1, 1, 1] Units => unitless Attribute => 1 _FillValue = 3.402823E+038 Attribute => 2 long_name = Global Monthly Surface Data Attribute => 3 units = unitless Attribute => 4 valid_range = 0.0000000 0.0000000 ______________________________________________________________________ 313 WN Surface Emissivity Data Type => FLOAT DFNT_FLOAT32 Dimensions => 3 [ 1, 1, 1] Units => unitless Attribute => 1 _FillValue = 3.402823E+038 Attribute => 2 long_name = Global Monthly Surface Data Attribute => 3 units = unitless Attribute => 4 valid_range = 0.0000000 0.0000000 ______________________________________________________________________ ================================================================================ End of File Updates: May 18, 2006: Research Systems, Inc. changed to ITT Visual Information Solutions Aug 03, 2010: changed link for IDL VM Dec 07, 2011: changed larc@eos.nasa.gov to support-asdc@earthdata.nasa.gov changed link for ITT VIS to Exelisvis