Prsentation PowerPoint

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Unified Data Accessusing XML Schema and XQuery
Serge RIAZANOFFGAEL ConsultantSerge.Riazanoff_at_ga
el.fr
GAEL-P160-SLD-001-01-00 GAEL Consultant,
Champs-sur-Marne, France
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Plan

• GAEL Consultant experience
• DRB (Data Request Broker) Extending XML
  strengths
• XML - to represent metadata
• XML Schema to validate XML documents
• XSLT to transform XML documents
• XSL-FO to render into printable formats
• XQuery to access data
• DRB architecture
• DERBY An application built on top of DRB
• Application 1 Sharing knowledge description
• Application 2 Towards semantic transcriptions

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GAEL Consultant experience

• EO activities since 1990
• relevant software developments
• photo-interpretation, image processing
• ortho-rectification (SPOT, Landsat, IRS, Aero,
  etc)
• format decoding (up to 23 EO formats on
  CDROM,CCT,DLT,etc.)
• product direct ingest (LiveLink)
• quality control and product editor (based on
  LiveLink technology)
• cartographic production and other EO services
• ortho-images, mosaics, spacemaps, etc.
• Consulting EO products Quality Control
• from stations to end-users
• ESA, SPOT IMAGE, TELESPAZIO
• CCR-ISPRA, ELF, TELESPAZIO, Ministry of
  Agriculture, CGG

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DerbySoftware
DRB
extension
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XML Schema

• Advantages of XML Schema
• Describes and constrains logical structure
• Already exists, XML based, opened technology
• Problems for EO products
• Assumes XML syntax (character encoding)
• Does not provide support forthe physical
  structure
• A solution for EO products
• New namespace and markups extending XML Schema

ltschema xmlnshttp//www.w3.org/2001/XMLSchema/
xmlnsdrbhttp//www.gael.fr/drb/gt ltcomple
xType nameMPHgt ltsequencegt ltelement
nameFileName typeStringgt
ltdrbbyteOffsetgt0lt/drbbyteOffsetgt
lt/elementgt lt/sequencegt lt/complexTypegt
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Document Object Model (DOM)

• Standard programming interfaces for accessing XML
  documents (W3C)
• DOM does not already support all W3C features
• XML Schema (type support is not foreseen before
  DOM Level 4)
• XPath 2.0
• XQuery
• New  Data Request Broker  (DRB)
• Removes DOM dependencies from XML syntax
• Compatible with XML Schema, XQuery
• Supports large tree representation
• DRB implementations
• XML documents
• Structured Data File (SDF) dedicated to the
  handling of EO products

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XML Query

• XPath 2.0 to locate data within documents
• XQuery syntax (W3C)
• Simple or constrained selections
• Conditional expressions
• Built-in functions
• Joins
• Transformations (supercede XSLT ?)

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XQuery - Simple selections

• document(MER_RR__1P)/mds1//mdsr/toa_rad

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XQuery - Joins

• FOR
• p1 IN document(MER__RR)/mds1//mdsr ,
• p2 IN document(ATS)/mds2//mdsr
• WHERE p1/time p2/time
• RETURN count(p1)

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XML Stylesheet Language

• XSLT for transformations
• XSLT is an implementation of XML
• Transformations of semantic
• XML to XHTML, MathML, SVG, etc.
• Translation of physical format with DRB
• May be replaced by XQuery
• XSL-Formatting objects (XSL-FO)
• XSL-FO is an implementation of XML
• Rendering into printable formats (PDF, RDF, RTF,
  etc.)

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DRB architecture
 
Applications
XQueryscripts
Data Request Broker (DRB)
XQuery Engine
Interface
Facilities
Schema
XML
File
SDF
HDF
Implementations
XML Schema
Directories Files
XMLdocs
HDFfiles
Binary files
Data sources
ENVISAT-PDS Formats Landsat 5/7 CEOS, Fast SPOT
123-4 etc.
CEOS ICF SPOT 5 - DIMAP
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Derby software

• Browse the documents
• Edit and execute XQuery scripts
• Render query results intoconfigurable plots,
  tables or reports

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Application 1 Sharing knowledge description
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Application 2 Towards a generic transcription
1 Physical logical transcription
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Application 2 Up to a generic transcription
2 - Logical transcription (DRB)
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Application 2 Up to a generic transcription
3 - Generic transcription
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Conclusions

• DRB is not an extra format but a technology
  to describe formats a description of the
  physical and logical organisation
• Sharing a networked knowledge
• Next step to the genericity modelling the
  multi-disciplinary semanticW3C RDF (Resource
  Description Framework)