1. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Data Discovery and Metadata Query Using Characterisation DM Igor Chilingarian (CRAL Observatoire de Lyon, France/SAI MSU, Russia) on behalf of Characterisaton subgroup of DM WG

2. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Commonalities of DAL protocols Query interfaces of: SIAPSSAPSLAP STAP (Astrogrid) In all the cases query is constructed using “mnemonic” parameter names, for example POS=180,10&SIZE=1.0&BAND=4e-7/5e-7 In all cases “mandatory” query parameters correspond to the characterisation DM elements

3. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Using Characterisation DM Query interface we propose: Usage of the “axis” concept to “universalize” the queries on different physical parameters. Usage of at least first and at most second level of the characterisation metadata Axes are identified by their UCDs list of available axes should be given by the getCapabilities query (or its analogue) Usage of complete characterisation UTYPEs as http-get (post) parameter names Additional parameters (not covered by characterisation DM) should be given by the getCapabilities query

4. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Example 1. Accessing Spectra spectral: give me all the flux calibrated data from the archive with the central wavelength between 4500A and 4900A, with a starting wavelength not longer than 4200A, with a finishing wavelength not shorter than 6000A, having FWHM spectral resolution between 1A and 2A, http://my-vo.org/finddata? axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& axis1.coverage.location.Coord.Coordinate.value=0.45/0.49& axis1.coverage.location.Coord.Coordinate.value=0.45/0.49& axis1.coverage.bounds.limits.LoLimit=/0.42& axis1.coverage.bounds.limits.LoLimit=/0.42& axis1.coverage.bounds.limits.HiLimit=0.6/& axis1.coverage.bounds.limits.HiLimit=0.6/& axis1.resolution.refval=0.0001/0.0002& axis1.resolution.refval=0.0001/0.0002& axis2.ucd=phot&axis2.calibrationStatus=1 axis2.ucd=phot&axis2.calibrationStatus=1

5. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Example 2: Images images: give me all the flux calibrated data from the archive with the central wavelength between 4000A and 10000A, with the right ascension of the centre between 12h and 18h, and declination of the centre >+88 deg, having FWHM spatial resolution not less than 3.6 arcsec. Interesting: this query should also return 3D spectroscopic data if they exist in the archive. http://my-vo.org/finddata? axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& axis1.coverage.location.Coord.Coordinate.value=0.4/1.0& axis1.coverage.location.Coord.Coordinate.value=0.4/1.0& axis2.ucd=pos&axis1.calibrationStatus=1&axis1.unit=deg& axis2.ucd=pos&axis1.calibrationStatus=1&axis1.unit=deg& axis2.coverage.location.Coord.Position2D.Value2.c1=180/270& axis2.coverage.location.Coord.Position2D.Value2.c1=180/270& axis2.coverage.location.Coord.Position2D.Value2.c2=88/90& axis2.coverage.location.Coord.Position2D.Value2.c2=88/90& axis2.resolution.refval=0.001/& axis2.resolution.refval=0.001/& axis3.ucd=phot&axis3.calibrationStatus=1 axis3.ucd=phot&axis3.calibrationStatus=1

6. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Example 3: 3D data (IFU, Fabry-Perot,…) 3D spectra: give me all the flux calibrated data from the archive with the central wavelength between 4500A and 4900A, having FWHM spectral resolution between 1A and 2A, located at the area with the right ascension of the centre between 12h and 18h, and declination of the centre >+88 deg, having FWHM spatial resolution not less than 1.8 arcsec http://my-vo.org/finddata? ?axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& ?axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& axis1.coverage.location.Coord.Spectral.value=0.45/0.49& axis1.coverage.location.Coord.Spectral.value=0.45/0.49& axis1.coverage.bounds.limits.LoLimit=/0.42& axis1.coverage.bounds.limits.LoLimit=/0.42& axis1.coverage.bounds.limits.HiLimit=0.6/& axis1.coverage.bounds.limits.HiLimit=0.6/& axis1.resolution.refval=0.0001/0.0002& axis1.resolution.refval=0.0001/0.0002& axis2.ucd=pos&axis1.calibrationStatus=1&axis1.unit=deg& axis2.ucd=pos&axis1.calibrationStatus=1&axis1.unit=deg& axis2.coverage.location.Position2D.Value2.c1=180/270& axis2.coverage.location.Position2D.Value2.c1=180/270& axis2.coverage.location.Position2D.Value2.c2=88/90& axis2.coverage.location.Position2D.Value2.c2=88/90& axis2.resolution.refval=0.001/& axis2.resolution.refval=0.001/& axis3.ucd=phot&axis3.calibrationStatus=1 axis3.ucd=phot&axis3.calibrationStatus=1

7. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Example 4: Atomic Lines spectral lines: give me all spectral lines of Hydrogen (ssp.atomicNumber), between 900A and 1500A with the final energy level between 13.5 and 13.7 eV (get Lyman series). “ssp” means Service-Specific Parameter http://my-vo.org/finddata? ?axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& ?axis1.ucd=em&axis1.calibrationStatus=1&axis1.unit=um& axis1.coverage.location.Coord.value=0.09/0.13& axis1.coverage.location.Coord.value=0.09/0.13& axis2.ucd=phys.energy%3Bphys.atom.final%3Bphys.atom.level& axis2.ucd=phys.energy%3Bphys.atom.final%3Bphys.atom.level& axis2.unit=eV&axis2.calibrationStatus=1& axis2.unit=eV&axis2.calibrationStatus=1& axis2.coverage.location.Coord.value=13.5/13.7& axis2.coverage.location.Coord.value=13.5/13.7& ssp.atomicNumber=1 ssp.atomicNumber=1

8. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006Caveats UCD 1+ may contain “;” that is equivalent to “&” in the HTTP_GET Query length may exceed 4096 bytes allowed for HTTP_GET Upper/lower case issue: parameters are case- sensitive for HTTP_GET, but UTYPEs are case- insensitive

9. IVOA Interoperability Meeting – Victoria, BC – 18 May 2006 Useful Features Easy conversion into XQuery Logical extension: use ADQL/x instead of http-get query No more discussions on the names of the parameters!