An Overview of HDF-EOS (Part II)

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An Overview ofHDF-EOS(Part II)

• Doug Ilg
• Raytheon STX
• Doug.Ilg_at_gsfc.nasa.gov
• [phone]

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Outline

• The Swath Interface
• What is an HDF-EOS File?

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Swath Data Sets
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A Swath Structure
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Components of the Swath Interface

• Access
• Definition
• Basic I/O
• Inquiry
• Utility
• Subset

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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.

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Swath Subsetting Features

• By Time
• SWdeftimeperiod/SWextractperiod
• By Geolocation
• SWdefboxregion/SWextractregion
• By Vertical field
• SWdefvrtregion/SWextractregion
• Tip use Time or Geolocation first, then Vertical

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Compression Methods for Swaths

• Run-Length Encoding
• Adaptive Huffman
• Gzip

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Question

• Whats an HDF-EOS File?

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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

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My Answer

• Youve asked the wrong question.
• The difference between HDF and HDF-EOS is at the
  object level, not the file level.

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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
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• 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
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• 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
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• 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

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• Services Provided
• Portability
• Elementary data access
• Moderate self-description
• Geolocation information tightly coupled to some
  of the data
• Partially standardized geographical subsetting

HDF-EOS

• Services Not Provided
• ECS ingest, archiving, search, and distribution
• Enhanced self-description
• Fully standardized geographical subsetting

An HDF file with a mixed set of HDF-EOS and
HDF data objects
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• 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
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• 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

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• 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