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An Overview of HDF-EOS (Part II). Doug Ilg Raytheon STX Doug.Ilg@gsfc.nasa.gov (301) 441-4089. Outline. The Swath Interface What is an HDF-EOS File?. Instrument. Scan Lines. Instrument Path. Along Track. Swath Data Sets. Dimension Name: Scan Size: 16. “Temp”. “Time”. Dimension
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An Overview ofHDF-EOS(Part II) Doug Ilg Raytheon STX Doug.Ilg@gsfc.nasa.gov (301) 441-4089
Outline • The Swath Interface • What is an HDF-EOS File?
Instrument Scan Lines Instrument Path Along Track Swath Data Sets
Dimension Name: Scan Size: 16 “Temp” “Time” Dimension Name: Track Size: 42 Dimension Name: Geotrack Size: 21 Map1 DataDimension: “Track” Geodimension: “Geotrack” Offset: 1 Increment: 2 A Swath Structure
Components of the Swath Interface • Access • Definition • Basic I/O • Inquiry • Utility • Subset
Tips on Writing a Swath • Order of calls is significant: • define dimensions before using them to define fields of maps • setting a compression method affects all subsequently defined fields • Unless a dimension map is defined, a 1-to-1 mapping is assumed during subsetting. This can produce strange results.
Swath Subsetting Features • By Time • SWdeftimeperiod/SWextractperiod • By Geolocation • SWdefboxregion/SWextractregion • By “Vertical” field • SWdefvrtregion/SWextractregion • Tip: use Time or Geolocation first, then Vertical
Compression Methods for Swaths • Run-Length Encoding • Adaptive Huffman • Gzip
Question: What’s an HDF-EOS File?
Some Answers • ECS: An HDF file with ECS metadata • Any file with an HDF-EOS object in it • A file with only HDF-EOS objects in it
My Answer You’ve asked the wrong question. The difference between HDF and HDF-EOS is at the object level, not the file level.
HDF Key An HDF file One or more HDF-EOS data objects with attendant structural metadata HDF-EOS ECS Metadata Core and possibly Archive metadata One or more HDF data objects
HDF • Portability • Elementary data access • Basic self-description • Geolocation information tightly coupled to data • Fully standardized geographical subsetting • Moderate self-description HDF-EOS • ECS ingest, archiving, search, and distribution • Enhanced self-description ECS Metadata
HDF • Services Provided • Portability • Elementary data access • Basic self-description • Services Not Provided • Geolocation information tightly coupled to the data • Fully standardized geographical subsetting • ECS ingest, archiving, search, and distribution • Enhanced self-description An HDF file with a set of HDF data objects
Services Provided • Portability • Elementary data access • Moderate self-description • Geolocation information tightly coupled to the data • Fully standardized geographical subsetting HDF-EOS An HDF file with a set of HDF-EOS data objects • Services Not Provided • ECS ingest, archiving, search, and distribution • Enhanced self-description
HDF • Services Provided • Portability • Elementary data access • Moderate self-description • Geolocation information tightly coupled to some of the data • Partially standardized geographical subsetting HDF-EOS An HDF file with a mixed set of HDF-EOS and HDF data objects • Services Not Provided • ECS ingest, archiving, search, and distribution • Enhanced self-description • Fully standardized geographical subsetting
HDF • Services Provided • Portability • Elementary data access • ECS ingest, archiving, search, and distribution • Enhanced self-description ECS Metadata • Services Not Provided • Geolocation information tightly coupled to the data • Fully standardized geographical subsetting An HDF file with a set of HDF data objects with ECS metadata
Services Provided • Portability • Elementary data access • Geolocation information tightly coupled to the data • Fully standardized geographical subsetting • ECS ingest, archiving, search, and distribution • Enhanced self-description HDF-EOS ECS Metadata An HDF file with a set of HDF-EOS data objects with ECS metadata • Services Not Provided • None
HDF • Services Provided • Portability • Elementary data access • Geolocation information tightly coupled to some of the data • Partially standardized geographical subsetting • ECS ingest, archiving, search, and distribution • Enhanced self-description HDF-EOS ECS Metadata An HDF file with a mixed set of HDF and HDF-EOS data objects with ECS metadata • Services Not Provided • Fully standardized geographical subsetting