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Obscore DM v 1.1 Mireille Louys, Doug Tody, Patrick Dowler, Daniel Durand, Laurent Michel, François Bonnarel, Alberto Micol and the IVOA DataModel working group Sydney Interop Meeting, Oct 2015
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Points for the current update 1. Dimensions of the axes along which data are spanned s_dim1 Spatial s_dim2 em_dim Spectral t_dim Temporal pol_dim Polarization 2. Wording for these quantities: samples, elements, bins, ? 3. How to accomodate dimensions for an event list : number of events? 4. Previous intermediate version had Utypes strings fixed
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More use-cases asked in Sesto (1) Use case 3.10 Show me a list of all data, For a selected list of SDSS objects that satisfies: 1.DataType=Cube with 3 dimensionsdataproduct_type = cube 2.Axes includes WAVEem_ucd=em.wl 3.Axes includes more than 200 pixels along each spatial axis s_dim1 and s_dim2 > 200 4.Spatial resolution better than 2 arcsecs_resolution <2 Appendix A. in the ObsCore specification
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More use-cases asked in Sesto (2) Use case 4.3 Show me a list of all data matching a particular event (e.g. gamma ray burst) in time interval and space: 1.DataType=time series 2.RA includes 16.00 hours 3.DEC includes +41.00 4.Time start > MJD 54221 and Time stop < MJD 55800 5.Number of time slots > 1000 Tested in TapHandle on ObsTAP services SELECT TOP 100 ivoa.ObsCore.access_url,ivoa.ObsCore.obs_id FROM ivoa.ObsCore WHERE (CONTAINS(POINT('ICRS', ivoa.ObsCore.s_ra, ivoa.ObsCore.s_dec), CIRCLE('ICRS', 10.684667, +41.268750, 0.016666666666666666)) = 1) AND ivoa.ObsCore.dataproduct_type = 'timeseries' AND ivoa.ObsCore.t_resolution > 60 AND ivoa.ObsCore.t_min > 54221 AND ivoa.ObsCore.t_max 1000
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Event list use-cases Show me a list of all event lists observed in the XMM data collection within the region covered by a particular image of GALEX data collection. 1.DataType = event list 2.Region contains polygon P1 extracted from the foot print of a particular GALEX image 3.Data collection= XMM 4.Instrument name=EPN SELECT xmm.access_url,xmm.obs_id FROM ivoa.ObsCore AS xmm JOIN ivoa.ObsCore as galex ON (CONTAINS(REGION(galex.s_region), REGION(xmm.s_region)) = 1) WHERE xmm.dataproduct_type = 'eventlist' AND galex.facility_name = ‘GALEX’ AND galex.dataproduct_type = 'image' AND xmm.facility_name = ‘XMM’ AND xmm.instrument_name = ‘EPN’
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Data content search All characterisation axes are supported s, em, t, pol More dedicated parameters Detection limit SNR Nb of sources in an image field Number of Events … are not part of Obscore Data Model
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How to advertise use-case and working examples ?An example Web page attached to TapHandle? ? An implementation note? ? Other
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Document release schedule Update from this discussion Will be uploaded on ivoa.net/Documents Will be circulated on dm mailing list Discussion page at http://wiki.ivoa.net/twiki/bin/view/IVOA/ObsCoreDMvOnedotOne By 10 November 2015
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Nature of the spectral axis How can I expose radio data in frequencies? How can I expose velocity cubes in km/s? em_ucd : em.wl, em.freq, em.dopplerVeloc.opt, em.dopplerVeloc.rel, … em_unit : any spectral unit following VOUnits spec ObsTAP constraints: Restricted units for spectral range in data discovery Data link services can bind the adequate description
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Redshift ObsCore DM fields DOPPLER CHARACTERISATION (RedShift) d_ucdChar.DopplerAxis.ucdunitlessstringNature of the Doppler axisNO d_unit Char.DopplerAxis.unitunitlessstringUnits along the Doppler axisNO d_calib_statusChar.DopplerAxis.calibrationStat us unitlessenumType of Doppler coord calibrationNO d_reference_posit ion Char.DopplerAxis.ReferencePosit ion unitlessenumPhase space origin for Doppler velocity, also named Reference Position in STC REC, Section 4.4.1.1.1 YES d_definitionChar.DopplerAxis.definitionunitlessenumDoppler velocity definition: RADIO, OPTICAL, RELATIVISTIC, as in STC REC, Section 4.4.1.4.2 YES d_minChar.DopplerAxis.Coverage.Boun ds.Limits.LoLimit km/s (def) doubleStart in Doppler coordinatesYES d_maxChar.DopplerAxis.Coverage.Boun ds.Limits.HiLimit km/sdoubleStop in Doppler coordinatesYES d_res_powerChar.DopplerAxis.Resolution.Res olPower.refval unitlessdoubleValue of the resolving power along the Doppler axis. (Reference) YES d_res_power_minChar.DopplerAxis.Resolution.Res olPower.LoLimit unitlessdoubleResolving power min value on Doppler axisNO d_res_power_maxChar.DopplerAxis.Resolution.Res olPower.HiLimit unitlessdoubleResolving power max value on Doppler axisNO d_resolutionChar.DopplerAxis.Resolution.refv al.value km/sdoubleValue of Resolution along the Doppler axisNO d_stat_errorChar.DopplerAxis.Accuracy.StatE rror.refval.value km/sdoubleDoppler Coord statistical errorNO
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Articulation of current data models ObsCore DM Discovery oriented Dataset DM Abstract view on generic datasets Two views on a common set of metadata Take the benefit of each Recognise the historical progression : Obscore has been an efficient test bed for assessing the benefits of a common description accross archives to foster interoperability. How to homogeneise ? Obscore:Observation Obscore:Dataset like in DatasetDM
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