Subsetting at UAH
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The document discusses the HDF-EOS Web-based Subsetter (HEW) and the new HDF Subsetting Engine (HSE) designed to provide users with targeted science data efficiently by allowing custom subsetting of datasets. It outlines the capabilities of HSE including spatial, temporal, and spectral subsetting, alongside benefits such as reduced analysis time and resource usage. The document also details the integration of HSE with existing data systems and its various applications, highlighting its accessibility for users without the need for full HEW installation.
Subsetting at UAH
- 1. Subsetting at UAH Bruce Beaumont, Matt Smith, Helen Conover, Sara Graves HDF & HDF-EOS Workshop VIII 2004 October 26-28 Aurora, CO
- 2. Why Subset? • Goal: to provide a science data user with only the data they need as quickly as possible. • Benefits science data users and data centers: - Reduces analysis time by reducing amount of data - Reduces time for data delivery - Reduces resources (network, personnel, media, etc.) • Steps: - Locate spatial / temporal / spectral area of interest - Extract - Re-assemble for distribution/use
- 3. What is HSE? HEW Subsetting Engine A new packaging option for the HDFEOS Subsetter designed for users that want subsetting, but do not want to host the full HEW installation or even the standalone HEW back-end.
- 4. What is HEW? • HDF-EOS Web-based Subsetter – Prototype software designed to be datasetindependent (HDF-EOS) – Funded by NASA/ESDIS for EOS-DIS – To be used within ECS (EOS-DIS Core System) – Original Front-end/GUI (optional) • Uses HTML forms and JavaScript – Original Back-end • Needed subset criteria and HDF-EOS data • Performed subsetting as a “batch” job
- 5. What are HSE’s capabilities? • Versions available for HDF-EOS 2 and HDF-EOS 5. • Subsets multiple files in one call. • Subsets properly-formatted HDF-EOS grid and swath objects. • Subsets spatially by latitude/longitude or row/column. • Subsets swaths temporally by date/time range. • Subsets swaths by full or partial (subscan) lines. • Subsets spectrally by HDF-EOS field. • Subsamples along any dimension by stride (repeating interval) or by discrete index list. (see chart) • Copies all file and field attributes to the output file and updates HDF-EOS “core” metadata when possible.
- 6. Stride Subsampling on a Dimension •STRIDE = 2 0 1 2 3 4 5 6 7 8 9 7 8 9 Selected Indexed Subsampling on a Dimension •INDEXES = (1, 3, 4, 5, 7) 0 1 2 3 4 5 Selected 6
- 7. Existing HEW Back-End Architecture Subset t ing crit eria ( ODL) St at us file End -user E-mail HEW_ DISS Input file( s) Out put file( s) Log file • Front end supplies subsetting criteria file • Subsetter writes messages to status file • Subsetter writes messages to log file • Subsetter sends e-mail to end-user Many sites do not want to create ODL files or the hassle of dealing with message or log files or e-mail.
- 8. New HSE Architecture All subsetting functionality is contained within a callable function • User Applicat ion Code Subset t ing crit eria Ret urn code • Input file( s) HEW Subset t ing Engine funct ion HSE_ LogMsg callback HSE_ St at usMsg callback Out put file( s) • User application code builds subsetting criteria structure Subsetting engine function calls user’s functions for status and log messages No e-mail is sent
- 9. SPOT • Subsettability “checker” – Displays content/structure of HDF-EOS4 (or HE5) files – Examines files for subsettability by HSE – Simple command-line interface – Stand-alone operation – Available at subset.org
- 10. HEW integration with ECS EDG System EDG Order submission (HTML) End user ECS 2 ECS 1 7 3 Output data (Reingested) 4 Data order and reply Subset ODL and reply Output data 6 Subsetter Subsetting System 5 Input data
- 11. Product Availability Matrix HDF-EOS 2 (HDF4) HDF-EOS 5 (HDF5) SGI • Sun • Linux N/A N/A SGI • Sun • Linux HEWBE SGI • Sun • Linux Planned HEW SGI • Sun • Linux N/A Product HSE HSE-5 SPOT SGI • Sun • Linux
- 12. Currently Available/Planned Subsetting Applications • HDF-EOS Subsetting Engine (HDF-EOS, HE5)Status Deployments – – – – – – • Complete System Subsetting Engine Only SPOT - Subsettability Checker HSE Integrated with ECS Data Order System HSE Integrated with AMSR-E Processing Subsetting as a Web Service GHRC GSFC many NSIDC, EDC AMSR-E SIPS (ECHO) available available Science teams GHRC in work (various) Customized Subsetting – MODIS tools – Coarse-grain SSM/I Subsetter • available available available available available planned General Purpose Customizable Subsetting – Subsetting Tool using ESML