1. Lessons learnt with Aladin and characterization experience for SIA2.0 F.Bonnarel, CDS (credit to Aladin developpers, CADC,ECF,ESAC, ESO VO people, DAL and DM IVOA WG)

2. SIA 1.0 (2002 !!!) Pros: –Solved the availabilty issue in a standard way for the first time. –Gave some rather unformal description/characterization of the images Limitations: –No mapping on datamodel –Ad hoc UCDS and no utypes –No structuration of the query response. –No staging

4. Query phase: extended ROI Extend ROI requests to all or a significant subset of stc AstroCoordArea –Use case: Draw a contour on top of a Preview or a wide field image and use it as a ROI. –Trick : drawn contours are on the image plane How to translate that in string stc in some given coordinate system….

6. SIA 2.0 Query interface: SSA 1.0 + ??? Requests by more characterization utypes (sampling in combination with resolution) More request by ranges (resolution and sampling) Add query by Observation/characterization utypes using « utype Extended » ADQL as it is proposed for TAP  (non redondant with parameter= value for level 3 or 4 queries)?

7. Query response: extended datamodel usage Use of Curation, Target, DatasetID and Characterization as in SSA. Extend SSA Characterization package towards full level 2 for resolutions and sampling for spatial and additional sampled axes ( spectral or whatever) Level 3 and Level 4 maybe available through DAL Extension mechanism (described in SSA): –Level 3 example : footprint description –Level 4 = PSF described as a link to a PSF service (eg TERAPIX qualityfits ) JPEG visualized in Aladin –Level 4 = Filter transmission curve available in Aladin

9. Query response: Dataset linkage Provenance: – instrumental (heavy stuff in FITS keywords) –Processing ( calibration --- links to unprocessed data, ancillary data) Access and views of complex or heterogeneous data (Linkage model) –Linkage to some simple derived datasets or excerpts of the main dataset (heterogeneous DAL protocols, generic dataset discovery) Parallel development of a provenance or dataset linkage datamodel by DM WG

12. Staging/Asynchronous access Individual images may need heavy statistical processing (Bayesian fusion, Markov multispectral segmentation) –as eg CDS/LSIIT collaboration has shown. Extremly faint source detection Image cleaning from cosmics … Nice to get staging facility to access results later from another aladin session replaying the original images sequences for comparison… –Idea: original query response give acref to process follow up page, – replaced by standard DAL (image, spectrum, table) query response when processing is completed –Interface has only to keep track of original acref ….