XML for taming data to be visualized over the Grid

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XML for taming data to be visualized over the
Grid within the gViz project

• RD in Grids e-science is transforming-
• - data access and
• discipline-oriented data e.g. -
• Marine XML
• Earth Science Markup Language
• NERC Data Grid
• CCLRC Data Portal

But there is still a gap to be bridged between-

multiple data formats and models
multiple preferred visualization systems
and
Precious legacy data
Programming script oriented e.g. Matlab
Satellite data HDF5
MVE e.g. Iris Explorer
New data
Joe Bloggs data
Application-oriented XML
Toolkit e.g. VisAD, PV3
??

• Conventional approaches-
• - Thats easy, Ill write a converter
• Collaborating team uses just one viz system
• But Grid-enabled VO encourages teams that
• form, change and disperse
• are multidisciplinary
• So we would prefer to have-

Precious legacy data
Programming script oriented e.g. Matlab
Satellite data HDF5
MVE e.g. Iris Explorer
New data
Joe Bloggs data
Application-oriented XML
Toolkit e.g. VisAD, PV3
. move from Axmxn to BxmCxnD (and avoid
making B,C,D too big)

• Investigating an approach which-
• Processes structure by sequence of filters
• Relies on effective coordination of filters (e.g.
  skML?)
• Processes bulk data (e.g. re-sequence) as late as
  possible (lazy transformation) e.g. use handles
• Bulk data can be text-based or binary
• Uses intermediate XML-based language - e.g.
  XDFor GGFs DFDL (Data Format Definition
  Language) to express structure.
• If not XML, then expresses structure in XML as
  early as possible
• Each filter should be straightforward e.g.
• Splitter/combiners XML transforms (XSLT)
  regular expressions
• Uses existing tools e.g. XSLT, OGSA-DAI
• Each filter should be expressable as a Web/Grid
  Service

Current work, investigating- Feasibility for
small set of diverse data sources and viz
systems Extent of performance loss for bulk data
cf existing alternatives Convenience for new
combination of data source D and viz system
V Framework for processing components Future Feasi
bility and benefit for highly structured
data Xquery / XPath 2.0 Frequently updated data
(simulations, experiments) More general metadata
(not only structure)
I am interested in testing the approach with
diverse datasets. Please contact
Julian.Gallop_at_rl.ac.uk
viz system-specific
XML front end
large legacy
subset handle
intermediate language
viz system
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e.g.