InterOpMay2005 VOTable

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Participants

F. Ochsenbein (FO), G. Lemson (GL), M. Taylor (MT), A. Preite-Matrinez, S. Derriere, R. Hook, J. Lindroos, A. Kembhavi, J.M. Desert (JMD), T. Takata, S. Honda, M. Tanaka, D. Sforna, A. Alan (AA), R. Gutierrez Sanchez, N. Moreau, J. Gupchup (JG), N. Urunkar, B. Hajime, J.C. Mc Dowell (JCM), B. Debray

Timetable

Time	Work Pkg	Content	Leader
14:00-15:00		VOTable applications and Questions
14:00		About C++ Parser and CONVOT	Nilesh Urunkar
14:20		About STIL/STILTS/TOPCAT	Mark Taylor
14:40		Improvement of the VOTable schema	Gerard Lemson
15:00-15:30		UCDs and utypes
15:00		UCD1+	Sebastien Derriere
		utype connection	Jonathan McDowell
16:00-17:00		COOSYS vs stc:AstroCooSystem
16:00		STC	Arnold Rots
16:15		Discussion
17:00		Other Questions (other datatypes,serializations,...)

Materials and notes from the work group and plenary sessions

VOTable session meeting notes (monday PM)

Introduction (FO)

Starlink VOTable software (MT) [[][slides]]

STIL: generic table processing library.

• Full implementation of VOTable standard
• Non catastrophic schema changes easily supported
• Table-aware DOM, table-aware SAX

TOPCAT

STILTS (STIL Tool Set)

• votcopy : converts DATA encoding
• volint: parsing VOTable and warning for troubles

Discussion

• MT remarks that future developments is uncertain (funding issues)
• Usage : JCM is using it and happy with it!
• AA asks precisions on the usage of volint: more intended for VOTable producer than for end user

VOTable C++ parser (JG) [[][slides]]

• C++ non-streaming parser (supports binary+FITS), using xerces+xalan
• VOTable streaming parser: v2.0 release 2005, april 8 (support VOTable v1.0 and 1.1, and Binary + FITS data)
• VOPlot : visualization toolkit (VO-India) 2D, 3D. Forthcoming release: support multiple table/resources. Integration with tools VOStat, GalICS

Discussion

• MT: How many points in plot?
• No technical limit, depends on memory. Tests are being done, but >1million points with regular desktop machine should work.

• JMD: Ability to plot VOTables with errors?
• Not likely if VOTable is really bad formed. VOPLot relies on SAVOT parser, so it will have same flexibility (true also in case of schema changes: use new version of SAVOT).

• GL: VOPlot as applet: bit hard to use.
• JG: Release of documentation soon.

Suggested changes in schema (GL) [[][slides]]

No element ref construct

No global elements for attributes and contained classes

Analogy to java binding / inheritance

Discussion

• Not a lot of discussion on ML so far
• PARAM inherited from FIELD would be an improvement: agreed
• GL: We could deal with documents only containing TABLE, with no VOTABLE element
• No opposition in the room: suggestion to change schema to version 1.11 with GL's suggestions

UCD (slides)

Reminder differences between ucd and utype attributes.

Issues: how to distinguish if the contents of the ucd attribute is a UCD1 or a UCD1+? Different possibilities:

• impose that from VOTable version 1.2 only UCD1+ is used
• ucd="UCD1+", and add new attribute for keeping track of UCD1
• ucd="UCD1", and add new attribute for giving of UCD1+

Discussion

Change in schema to accomodate full compliance with UCD1+ syntax (allow ':' char).

Favored solution is to impose the usage of UCD1+ starting with VOTable version 1.2. Better to change number from 1.1 to 1.2 (rather than 1.11) to indicate significant change. We keep the ucd attribute alone, and its content must be a UCD1+

utype syntax (JCM) [[][slides]]

• Currently, utype has type "String".
• Use XPATH-like syntax: sed:Segment/Frame/Time/Type
• Write short formal document defining the syntax.

Discussion

MT: Be careful that an exact XPath requirement is maybe not what we want (implies more than we want here).

JCM: ask again about XPath during DM discussion

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