1. Discussed in Kyoto Schema changes for the next version (Gerard Lemson)  will be included in VOTable1.2 Schema changes for the next version (Gerard Lemson)  will be included in VOTable1.2 ucd1 and ucd1+  just a replacement ucd1 and ucd1+  just a replacement datatypes limited to FITS set -- would extensions be needed (e.g. unsigned numbers, date+time, string,...)  no unanimity datatypes limited to FITS set -- would extensions be needed (e.g. unsigned numbers, date+time, string,...)  no unanimity vs  no real conclusion, will be discussed vs  no real conclusion, will be discussed

2. VOTable: back to basics VOTable is not a data model ! VOTable is not a data model ! A way to serialize data collections... A way to serialize data collections......while keeping full metadata contents...while keeping full metadata contents VOTable schema remains simple and flexible... VOTable schema remains simple and flexible... to cope with existing data sets (FITS) to cope with existing data sets (FITS) to be adaptable to ever changing data models. to be adaptable to ever changing data models.

3. VOTable is used in VO to express various collections to express various collections collections of astronomical sources (catalogues) collections of astronomical sources (catalogues) collections of images collections of images large time series large time series instrumentation, models,... instrumentation, models,... and needs stability for applications to run! and needs stability for applications to run! how can large data collections remain valid if data model is changing ? how can large data collections remain valid if data model is changing ?

4. Question of Astrometry Definition Current VOTable way (from V1.0) Current VOTable way (from V1.0) Does not apply to e.g. solar studies, moving frames -- VOTable has to be more generic Does not apply to e.g. solar studies, moving frames -- VOTable has to be more generic VO components have to be shared --- if STC is the data model of space+time coordinates, VOTable as well as other VO components has to refer to it. VO components have to be shared --- if STC is the data model of space+time coordinates, VOTable as well as other VO components has to refer to it.

5. Scenarios for Astrometry in VOTables 2 basic ways: include the STC schema and follow its directives in a changing world include the STC schema and follow its directives in a changing world make a reference to STC components via the utype reference make a reference to STC components via the utype reference

6. 1. Addition of STC schema Would be closer to a COOSYS replacement, BUT: AstroCoord requires all time+velocity+space definitions: would be so much better to have these disantangled (e.g. time series) AstroCoord requires all time+velocity+space definitions: would be so much better to have these disantangled (e.g. time series) AstroCoord defines labels & units as e.g. AstroCoord defines labels & units as e.g. RA,Dec Column3 Column4 Column5

7. Addition of STC schema (continued) AstroCoord requires coordinate components stored as an array -- inapplicable if e.g. single component is present (galactic latitude) AstroCoord requires coordinate components stored as an array -- inapplicable if e.g. single component is present (galactic latitude) Other VO models: should VOTable include all VO schemas (e.g. solar position, characterisation...)? Other VO models: should VOTable include all VO schemas (e.g. solar position, characterisation...)?

8. 2. STC referencing utype referencing: was originally created for DAL needs was originally created for DAL needs a consensus on an XPath expression: a consensus on an XPath expression: model:element/element...[attribute].../ model:element/element...[attribute].../ e.g. e.g. vot : VOTable/RESOURCE/TABLE[1]/FIELD[@name="RA"] vot : VOTable/RESOURCE/TABLE[1]/FIELD[@name="RA"]

9. Examples of possible STC referencing Referencing via a GROUP Referencing via a GROUP

10. STC Referencing Referencing individual components Referencing individual components <FIELD name="RAJ2000" datatype="double" utype="crd:AstroCoords[@coord_system_id='J2000-OPTICAL-ET']/ Position2D/Value2(1)"> <FIELD name="DEJ2000" datatype="double" utype="crd:AstroCoords[@coord_system_id='J2000-OPTICAL-ET']/ Position2D/Value2(2) ">

11. Referencing problem How to refer to a specific component of an array in XPath ? How to refer to a specific component of an array in XPath ? Again, disentangling the 3 position / time / velocity components would help... Again, disentangling the 3 position / time / velocity components would help... Would be better to adopt identical conventions in all VO components Would be better to adopt identical conventions in all VO components

12. Proposal adopt the utype way with adopt the utype way with utype="crd:AstroCoords[@coord_system_id='J2000- OPTICAL- ET ']/Position2D/Value2(1) "> utype="crd:AstroCoords[@coord_system_id='J2000- OPTICAL- ET ']/Position2D/Value2(1) "> individual or ? individual or ? is there a chance the components angular position / time / velocity are disentangled ? is there a chance the components angular position / time / velocity are disentangled ? as soon as STC is adopted as soon as STC is adopted crd: or stc: ? crd: or stc: ?  Share conventions with other VO components

13. VOTable Appendices what to do ? A.1 VOTable LINK substitutions  LINK question A.2 VOTable Query Extension  Registry ? A.3 Arrays of variable-length strings  String ? A.4 FIELDs as data pointers  LINK question A.5 Encoding individual table cells A.6 Very large arrays A.7 Additional TABLE attributes  (OK in VOTable1.1) A.8 Other serialization(s)

14. A1. LINK Questions LINK is required for several applications LINK is required for several applications SIAP: one of the columns gives a link to actual image server, coded in a SIAP: one of the columns gives a link to actual image server, coded in a Aladin: required to provide a link to the full data, coded in a LINK with substitutions Aladin: required to provide a link to the full data, coded in a LINK with substitutions A. Wicenec proposes a associated to A. Wicenec proposes a associated to  It is important !

15. Velocities and Distance estimations <FIELD name="RVel" ID="col4" ucd=" src.veloc;pos.heliocentric " datatype="int" width="5" unit="km/s"/> Distance of Galaxy, assuming H=75km/s/Mpc Example

16. LINK substitution (Aladin way) LINK substitution (Aladin way) a substitution filter is applied in the context of a particular row. For the first row of the table, the substitution would result in the URL http://ivoa.net/lookup?Galaxy=N++224&RA=010.68&DE=%2b41.27

17. LINK definition (INES way) LINK definition (INES way) Link to the spectrum file.....

18. A2 – Query Extension It is another view on the LINK: present the different parameters available for a query. Role of the registry ? Role of the registry ? these details stored in a "fine-grain" registry these details stored in a "fine-grain" registry in the context of a "coarse-grain" registry, some facility of getting these details must exist... in the context of a "coarse-grain" registry, some facility of getting these details must exist...

19. A3 – Arrays of variable-length strings Is related to the String datatype which does not exist in VOTable (FITS syndrome) Is related to the String datatype which does not exist in VOTable (FITS syndrome) FITS knows only a fixed-size array of variable-length strings (via the " Variable length array " convention) FITS knows only a fixed-size array of variable-length strings (via the " Variable length array " convention)

20. A4 - A4 - FIELDs as data pointers when a column contains a reference or a pointer to the data: UR[LI], cid (Content- ID),... when a column contains a reference or a pointer to the data: UR[LI], cid (Content- ID),... http://almasw.hq.eso.org/almasw/bin/view/Archive/VOTabl eDataTransfer http://almasw.hq.eso.org/almasw/bin/view/Archive/VOTabl eDataTransfer Add type="location" attribute to Add type="location" attribute to

21. A5 - A5 - Encoding individual table cells To decide to insert binary data at the cell level – typically an image – To decide to insert binary data at the cell level – typically an image – without the need for a break in the stream without the need for a break in the stream without having to encode the whole table without having to encode the whole table

22. <FIELD name="Spectrum" ucd="phot.fluxDensity" datatype="float" arraysize="*" unit="mW/m2/nm" precision="E3"/> NGC6543 SWS06 2028 QJKPXECHvndAgMScQHul40CSLQ5ArocrQLxiTkC3XClAq0OWQKQIMUCblYFAh753QGij10BT Em9ARKwIQExqf0BqbphAieuFQJS0OUCJWBBAhcrBQJMzM0CmRaJAuRaHQLWZmkCyhytAunbJ QLN87kC26XlA1KwIQOu+d0DsWh1A5an8QN0m6UDOVgRAxO2RQM9Lx0Din75A3o9cQMPfO0C/ dLxAvUeuQKN87kCXQ5ZAjFodQH0vG0B/jVBAgaHLQI7Ag0CiyLRAqBBiQLaXjUDYcrBA8p++ QPcKPUDg7ZFAwcKPQLafvkDDlYFA1T99QM2BBkCs3S9AjLxqQISDEkCO6XlAmlYEQKibpkC5 wo9AvKPXQLGBBkCs9cNAuGp/QL0euEC4crBAuR64QL6PXEDOTdNA2987QN9T+EDoMSdA8mZm QOZumEDDZFpAmmZmQGlYEEBa4UhAivGqQLel40Dgan9A4WBCQLNcKUCIKPZAk1P4QNWRaEEP kWhBKaHLQTkOVkFEan9BUWBCQVyfvg==

23. A6 - A6 - Very large arrays The BINARY serialization of variable-length arrays uses a 4-byte prefix for the number of items of the array. This convention imposes an absolute maximal number of 2^31 Possibility of an arrayprefix which could specify the size of the number of items Possibility of an arrayprefix which could specify the size of the number of items arrayprefix="unsignedChar" would imply max. 255 elements in the array arrayprefix="long" would accept > 2billion items

24. A7 - Additional TABLE attributes ucd and utype attributes ?   to drop from document (were adopted)

25. Data structure widely interpretable Messier Number <FIELD name="R.A.2000" ID="RA" ucd="pos.eq.ra" ref="J2000" unit="deg" datatype="float" width="5" precision="1" /> <FIELD name="Dec.2000" ID="DE" ucd="pos.eq.dec" ref="J2000" unit="deg" datatype="float" width="5" precision="1" /> <FIELD ID="T" name="Classification" datatype="char" arraysize="10*" ucd="src.class"> Classification (galaxy, glubular cluster, etc) <![CDATA[ MRADEClassification 3205.5+28.4Globular Cluster 31010.7+41.3Galaxy ]]> A8 - A8 - A new CSV serialization ?

26. Proposed Roadmap Generalisation of the utype mode to refer to components of data models Generalisation of the utype mode to refer to components of data models Agreement of utype syntax with other WG Agreement of utype syntax with other WG Precision of exact STC reference in agreement with DM and other WGs Precision of exact STC reference in agreement with DM and other WGs deprecate COOSYS ? deprecate COOSYS ? Rewrite the VOTable schema  VOTable1.2 Rewrite the VOTable schema  VOTable1.2 Appendices ? ? Appendices ? ?

27. And after? after discussion of the changes discussed here, discussion of a modified schema... after discussion of the changes discussed here, discussion of a modified schema... close the VOTable group ? close the VOTable group ? envisage other changes (e.g. Quantity-based serialisation ?) envisage other changes (e.g. Quantity-based serialisation ?)......