an International Virtual an International Virtual Observatory Observatory data exchange format data exchange format VOTable Roy Williams François Ochsenbein Clive Davenhall Daniel Durand Pierre Fernique David Giaretta Robert Hanisch Tom McGlynn Alex Szalay Andreas Wicenec
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An International Virtual Observatory data exchange format VOTable Roy Williams François Ochsenbein Clive Davenhall Daniel Durand Pierre Fernique David.
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an International Virtual Observatoryan International Virtual Observatory
</Date><Body>Io bisogno una appartamento acoglienti a Cremona …</Body>
4/13/23
April 13, 1723
17.iv.1723
Separation of structure from presentation
The computer can read the document:“Find all memos from April 1723”
VOTable
• Full metadata representation• Hierarchy of RESOURCEs• containing PARAMs and TABLEs• UCD (unified content descriptor)
– a has unit meter
– a has UCD ORBIT_SIZE_SMAJ (Semi-major axis of the orbit )
• Can reference remote and/or binary streams• Table can be
– Pure XML
– "Simple Binary"
– FITS Binary Table
VOTable Parentage
• Astrores• XML format for tables• Developed at CDS Strasbourg• Presented at ADASS 1999• Vizier implementation
• XSIL• XML format for Tables and Arrays• Developed at LIGO Caltech 2000• Extensible through Type-Class dynamic loading• Java parsing, browsing, editing• Matlab interface
PHOT.INT-MAG.B Integrated total blue magnitude ORBIT.ECCENTRICITY Orbital eccentricity STAT.MEDIAN Statistics Median Value INST.QE Detector's Quantum Efficiency
• Can be resolved by web service– to description, examples, etc
• Base + Specifiers• eg error in default right ascension• POS.EQ.RA, MAIN, ERROR
VOTable Friends
XML BinaryStreaming
Table Datacube Semantics
VOTable√ √ √ √
BinX√ √ √ √
MS Dataset √ √
HDF√ √
XDF√ √
Some “self-describing” file formats
XML Parsing
SAX: Event-BasedHandlers for StartElement, Text, EndElement, etc.
Found element BookCatalogueFound element BookFound Element TitleFound Text The Cambridge Star AtlasFound End Element Title….
Parsing
DOM: Document Object ModelReturns a tree-like Document object with data attached
BookCatalogue
BookBook
Title
ISBN Parallel Computing Works!
Cambridge Star Atlas
Title
Author
Wil Tirion
Binding to make a Parser
for(int i=0; i<table.getFieldCount(); i++){ Field field = (Field)table.getFieldAt(i); String u = field.getUcd(); if(u != null && u.equals("POS_EQ_RA_MAIN")) System.out.println("Field " + i + " is for RA"); }
From the Schema an API and library is generatedJAXBBreezeCastor