1. HDF-EOS 3.0 Functional and
Structural Design
David Wynne/Alex Muslimov
Emergent Information Technologies, Inc.
September 19, 2000
davidw@eos.hitc.com/amuslimo@eos.hitc.com

2. HDF-EOS 3.0
• Based on HDF5, with input from NCSA
with respect to Design, Implementation and
Method
• Working with EOS AURA teams to Refine
Design
• Primary Goal of Design -- minimal impact
to Heritage Code
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3. Current HDF-EOS 3.0
Functionality
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Basic File I/O
FillValues
Compression
Chunking/Tiling
Swath Interface
Grid Interface
FORTRAN Wrappers
Profile Interface
• Global, Group &
Local Attributes
• Extendable DataSets
• Test Drivers
• User’s Guide
• Subsetting
• SUN, SGI & DEC
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4. Functional Specification
•Swath File Access
SWopen, SWcreate, SWattach, SWdetach and SWclose
•Dimension/ Mapping Definition
SWdefdim, SWdefdimmap and SWdefidxmap
•Field Definition/Compression/Chunking
SWdefgeofield*, SWdefdatafield*, SWdefcomp and
SWdefcomchunk
•Field I/O, Inquiry and Info
SWwritefield, SWreadfield, SWinqdatafields, SWinqgeofield
and SWfieldinfo*
*Function interface has changed between HDF-EOS 2.x and 3.0
Function names italicized represent new functionality
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5. Functional Specification, cont.
•Attribute I/O, Inquiry and Info
SWwriteattr, SWreadattr, SWinqattrs, SWattrinfo
SWwritegrpattr, SWreadgrpattr, SWinqgrpattrs, SWgrpattrinfo
SWwritelocattr, SWreadlocattr, SWinqlocattrs and SWlocattrinfo
•General Inquiry and Info
SWinqswath, SWnentries, SWinqdims, SWdiminfo,
SWinqmaps, SWmapinfo, SWinqidxmaps and SWidxmapinfo
•Subsetting
SWdefboxregion, SWdeftimeperiod, SWregioninfo,
SWperiodinfo, SWextractregion and SWextractperiod
•Profile
PRdefine, PRread, PRwrite, PRinquire and PRinfo
Function names italicized represent new functionality
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6. Functional Specification, cont.
•HDF-EOS 2.6
SWdefdatafield(swathID, fieldname, dimlist, numtype, merge)
•HDF-EOS 3.0
SWdefdatafield(swathID, fieldname, dimlist, maxdimlist,
numtype, merge)
•Maxdimlist
New HDF5 functionality passed through. This allows the
user to set an upper limit to the size of the dataset.
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7. Top Level of HDF-EOS 3.0 File
Root -- /
HDFEOS
HDFEOS
INFORMATION
SWATHS
GRIDS
POINTS
Miscellaneous
Proposed Group, User Input
Group
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8. Top Level of HDF-EOS 3.0 File
HDFEOS
HDFEOS
INFORMATION
HDFEOSVersion
StructMetadata.0
Group
Attribute
Data
Set
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9. Swath Structure
SwathName
Global Attribute
<SwathName>:<AttrName>
Group Attribute
<DataFields>:<AttrName>
Local Attribute
<FieldName>:<AttrName>
Data Fields
Data
Field1
Profile Fields
Profile
Field1
Data
Fieldn
Geolocation Fields
Profile
Fieldn
Longitude
Each Data Field can have Attributes
Dimension
and/or Dimension Scales
Scale
Time
Latitude
CoLatitude
Shaded Objects are implemented in a fixed way so the
user doesn’t have direct access via the interface
DataField1:DIMENSIONLIST
Proposed Attribute, User Input
Group
Attribute
Data
Set
Message Attribute
<SwathName>:<AttrName>
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10. Profile Structure
SwathName
Global Attribute
<SwathName>:<AttrName>
Group Attribute
<DataFields>:<AttrName>
Profile Fields
Geolocation Fields
Local Attribute
<FieldName>:<AttrName>
Profile
Field1
Each Data Field can have Attributes
and/or Dimension Scales
Profile
Fieldn
Dimension
Scale
DataField1:DIMENSIONLIST
Longitude
Time
Latitude
CoLatitude
Message Attribute
<SwathName>:<AttrName>
Proposed Attribute, User Input
Group
Attribute
Data
Set
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11. Grid Structure
Global Attribute
<GridName>:<AttrName>
GridName
Group Attribute
<DataFields>:<AttrName>
Data Fields
Local Attribute
<FieldName>:<AttrName>
Message Attribute
<GridName>:<AttrName>
Proposed Attribute, User Input
Data
Field1
Attribute
Data
Fieldn
Each Data Field can have Attributes
and/or Dimension Scales
Dimension
Scale
DataField1:DIMENSIONLIST
Group
_BLKSOM:
Data
Set
Shaded Objects are implemented in a fixed way so
the user doesn’t have direct access
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12. Point Structure
Global Attribute
<PointName>:<AttrName>
PointName
Linkage
FWD
POINT
Object
Reference
Level1
Name
Object
Reference
Attribute
Local Attribute
<LevelName>:<AttrName>
Leveln
Name
Shaded Objects are implemented in a fixed way so
the user doesn’t have direct access
Proposed Attribute, User Input
Group
Group Attribute
<DataFields>:<AttrName>
Data
BCK
POINT
Message Attribute
<PointName>:<AttrName>
_LevelWritten
Data
Set
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13. Issues
• Maximum size of variable length and
compound data types
• Chunking with variable length and compound
data types
• Only deflation compression method
implemented.
• File size limit in ECS - Is two Gbytes enough?
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