VOTable 2005 Applications

Agenda Description of some applications Description of some applications Nilesh UrunkarAbout C++ Parser and CONVOT Nilesh UrunkarAbout C++ Parser and CONVOT Mark TaylorAbout STIL/STILTS/TOPCAT Mark TaylorAbout STIL/STILTS/TOPCAT Improvement of the VOTable schema Improvement of the VOTable schema Gerard LemsonAbout VOTable Schema Gerard LemsonAbout VOTable Schema UCD1, UCD1+ and utype in VOTable UCD1, UCD1+ and utype in VOTable Sebastien DerriereAbout UCDs and utype Sebastien DerriereAbout UCDs and utype Comment on utype (Jonathan McDowell) Comment on utype (Jonathan McDowell)Break

Agenda (continued) Coordinate system in VOTable Coordinate system in VOTable Arnold RotsAbout simple STC, LinearSTC? Arnold RotsAbout simple STC, LinearSTC? Discussion on implementations Discussion on implementations Open Questions Open Questions Other datatypes (dateTime, string,...) Other datatypes (dateTime, string,...) Other serializations (csv) Other serializations (csv) Commonalities with other VO components Commonalities with other VO components VOTable appendices VOTable appendices Future of the VOTable group ? Future of the VOTable group ?

UCDs UCD1 UCD1+ utype VOTable1.1 recommends the UCD1+ VOTable1.1 recommends the UCD1+ Several services (VOCone?) use UCD1 Several services (VOCone?) use UCD1 Could (should) VOTable specify both ? Could (should) VOTable specify both ? embedded in ucd attribute: embedded in ucd attribute: ucd="meta.id;meta.main=ID_MAIN" as an additional attribute ucd1="ID_MAIN" as an additional attribute ucd1="ID_MAIN" Both solutions need a schema modification...

Astrometry Definition Current VOTable way Current VOTable way Does not apply to e.g. solar studies, moving frames Does not apply to e.g. solar studies, moving frames better to keep common model across VO components better to keep common model across VO components

STC Problems and Questions Requires all time+velocity+space definitions when a simple frame is needed? Requires all time+velocity+space definitions when a simple frame is needed? the position must be specified as an array; can work with a GROUP ? the position must be specified as an array; can work with a GROUP ? referencing problem: the names of columns have to be enumerated ? What if several coordinates in the same system exist in one table (e.g. for binaries) ? referencing problem: the names of columns have to be enumerated ? What if several coordinates in the same system exist in one table (e.g. for binaries) ? units specified both in AstroCoord and FIELD possible contradictions units specified both in AstroCoord and FIELD possible contradictions How is the Epoch specified ? How is the Epoch specified ?

The wish for VOTable <FIELD name="RAJ2000" unit="deg" datatype="double" ucd="pos.eq.ra;meta.main" utype="stc:AstroCoordSystem ]/Axis1" > Right Ascension > Right Ascension

Question of datatypes Datatypes currently restricted to FITS, i.e. various types of integer, floating-point, and characters (assuming Unicode is a wide character) Datatypes currently restricted to FITS, i.e. various types of integer, floating-point, and characters (assuming Unicode is a wide character) Note: the UCD plays a role! Note: the UCD plays a role! Proposed: date+time, string Proposed: date+time, string

date+time datatype ? Should a date+time datatype be introduced (e.g. represented by ISO format T14:15:16) but Should a date+time datatype be introduced (e.g. represented by ISO format T14:15:16) but need accurate time definition, UTC is not enough... need accurate time definition, UTC is not enough... what about binary serialization ? what about binary serialization ? what about FITS serialization ? what about FITS serialization ?

string Datatype ? A standard datatype in XML, Java,... A standard datatype in XML, Java,... binary serialization could be solved binary serialization could be solved what about FITS serialization ? Variable- length array convention (with a heap) ? No! what about FITS serialization ? Variable- length array convention (with a heap) ? No!

Question of data serializations (not discussed) Currently 3 possible serializations: Currently 3 possible serializations: XML (ascii) XML (ascii) FITS binary/ascii table FITS binary/ascii table binary stream binary stream Frequently asked: tab-separated-values serialization (understandable by a lot of tools and databases) Frequently asked: tab-separated-values serialization (understandable by a lot of tools and databases) would be straightforward to implement would be straightforward to implement

VOTable future ? (not discussed) VOTable is heavily used, but: VOTable is heavily used, but: no much traffic on the discussion group (does it mean it's perfect?) no much traffic on the discussion group (does it mean it's perfect?) different models express similar concepts different models express similar concepts any wish ? any wish ?