HDF-EOS Subsetting Activites at the GES DAAC

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HDF-EOS Subsetting Activites at the GES DAAC

• By James Johnson,
• Arun Gopalan

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Why Subset?

• There are two main reasons
• Files are too large
• Files contain more information than needed
• Thus the data will be easier to use by the end
  user.

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Subsetting Cases

• Spatial - High spatial resolution by latitude and
  longitude
• Temporal - Data spanning a large time range
• Parameter - Lots of measured geophysical
  parameters
• Channel - High- or Hyper-spectral instrument data
• Algorithm - Special cases, such as retrieving
  only cloud-free regions

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Subsetting Methods

• On-The-Fly - On-line (anonymous ftp / data pool)
  data products
• On Demand - Near-line data products which are
  backed up in the tape archive.
• Production - Kicked off by an executable or PGE
  (through a subscription or for a pre-cut product)

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Subsetting Scenarios
Triggered Executable (PGE)
Subscription
Near-line Tape Archive
On-Demand
User
Data Producer
On-line FTP / Data Pool
On-The-Fly
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GES DAAC Subsetting Plans
Data Type Subset Type Subset Method
MODIS L0 Temporal On-the-Fly
MODIS L1B Channel On-the-Fly On-Demand Production
MODIS L2 Ocean Parameter On-Demand
MODIS L3 Ocean Spatial On-the-Fly On-Demand
MODIS L3 Atmosphere Parameter On-the-Fly
AIRS L1B Channel On-the-Fly On-Demand
AIRS L2 Parameter On-the-Fly On-Demand
GMAO Aura HIRDLS, MLS Parameter Production (Subscription)
Aura (HIRDLS, MLS OMI) Spatial Parameter Production (Subscription)

• Subsetting programs UAH HSE and in-house
  programs
• Access GES DAAC Web Interface (WHOM) and EDG