Tools and Examples that Improve the Interoperability of NASA HDF-EOS Data

MuQun Yang, Hyo-Kyung Lee, and Mike FolkThe HDF Group

The HDF Group has developed and maintained the following tools for the interoperability of NASA HDF and HDF-EOS data. Some tools are still under active development.

Use netCDF tools to access HDF-EOS via OPeNDAP

Use NetCDF-4 to access HDF-EOS5

Use HDF4 XML Map Writer to access HDF4 using generic file readers

http://hdfeos.org

This work was supported by cooperative agreement number NNX08AO77A from the National Aeronautics and Space Administration (NASA). Any opinions, findings, conclusions, or recommendations expressed in this material are those of the author[s] and do not necessarily reflect the views of the National Aeronautics and Space Administration.

HDF4/5 Files

Users

OPeNDAP Clients

OPeNDAP Servers

libnc-dap HDF4/5 Handlers

Terra/Aqua/Aura

Translation Layers

netCDF Visualization Tools

DAP

HDF5

HDF-EOS5

HDF-EOS5file HDF5

NetCDF4

NetCDF-4file

AugmentedHDF-EOS5

file

Augmentation

Use HDF-EOS2 Dumper to help the access of HDF-EOS2 using IDL and MATLAB

HDF4 File HDF4 Mapping File (XML document)

hmaplinked with HDF4 library

Readerprogram

Object Data Groups, Data Objects, Structural and Application

Metadata; Locations of Object Data

HDF-EOS2 File

HDF-EOS2 DumperExtract geo-location

information

LatitudeLongitude in ASCII file

HDF SDS Interface Text file InterfaceMATLABIDL

Example Usage: %eos2dump –a1m MYD02HKM.A2010031.0035.005.2010031183706.hdf

Example Latitude Output:-61.0802, -61.0949, -61.1096, -61.1241, -61.1387, -61.1531, -61.1675, -61.1818,-61.196, …

Use cases: HDF-EOS2 files with non-geographic projections, like SINSOID and SOM, and swath dimension maps.

MATLAB and IDL examples that use the HDF-EOS2 Dumper outputs

OPeNDAP Examples

HDF4 XML Map Writer Example

http://hdfeos.org

Acknowledgements: We thank Dan Marinelli, Carol Boquist and Rama Ramapriyan of the NASA ESDIS project; Christopher Lynnes, James Johnson and Fan Fang from NASA GES DISC; Ruth Duerr from NSIDC; James Gallagher from OPeNDAP, Inc.; Cheryl Craig from HIRDLS team; UCAR's NCL User Group and John Evans from MathWorks for their valuable suggestions and help.

NSIDC AMSR_E IDV NSIDC AMSR_E Panoply LaRC MISR Panoply

HDF-EOS5 Augmentation Tool Example

GRIDSHDFEOS

CloudFractionAndPressureData Fields

CloudFraction[XDim][YDim]CloudPressure[XDim][YDim]

XDim

YDim

Provide coordinatesrequired by netCDF-4.

[nLevels][nTimes]

Provide the connections between dimension and dimension scales.

Products supported: NASA Aura HIRDLS, MLS, OMI, TES, and

MEaSUREs GSSAP

Provide offset and bytesof HDF4 objects in XML.

/* Open the hdf file for reading. */ infile = fopen(hdfname, "rb"); if(infile == NULL) { printf("Error opening file: %s\n", hdfname); exit(EXIT_FAILURE); } /* Read the dataset into the buffer. */ buffer = malloc(nBytes); fseek(infile, offset, 0); fread(buffer, 1, nBytes, infile);Read binary data

with fseek() and fread() in C.

def __init__(self,hdf_fileName): try: #it opens the HDF creating a file object file_path=path.normpath(hdf_fileName) self.file_handler=file(file_path,"rb") …self.file_handler.seek(int(chunk.attrib["offset"]),0) #if chunk.attrib["compression"] in ("zlib","szip","DEFLATE"): tmp_buffer_object.write(self.file_handler.read(int(chunk.attrib["nBytes"])))Read binary data

with seek() and read() in Python.

LAADS MODIS Aqua IDL (Swath)

LP DAAC MODIS Terra MATLAB

(Grid)

NSIDC AMSR_E IDL (Polar Grid)

GES DISC MLS PanoplyGES DISC OMI IDV

GES DISC AIRS IDV

LAADS MODIS Panoply

LP DAAC MODIS IDV