1. The need for a stronger IVOA review process An SDM+SSA correctness assessment Bruno Rino, Nov. 8 2009

2. I am here today… Not as IVOADoc, but As a Data Provider (@ESO) – Doing an audit to ESO’s SSA Two reference documents – Spectrum Data Model (SDM), Oct 2007 – Simple Spectral Access (SSA), Feb 2008 I will show you inconsistencies – Not on the text itself, but from tables: where there is no place to interpretation

3. Huh? But… how is it possible? In SSA: “In this document we refer to the underlying data model interchangeably as the SSA data model or the Spectrum or spectral data model. The data model used in SSA is described in (McDowell, Tody, et.al, 2007).” “UTYPEs of standard fields are required for identification of interface elements and must be given and must comply with the SSA protocol (this document) and the Spectrum data model (McDowell, Tody, et. al. 2007).” But the SSA document repeats the SDM – Convenient, but error prone… and fallacious And also tries to fix the SDM – But with a wrong approach: the SDM should reflect the fixes!

4. Sources of information Spectrum Data Model (SDM) – Fields (3.6) – FITS serialization (9) Simple Spectral Access (SSA) – Query Response (4.2) – Data Model Summary (Appendix D)

5. General notes utype names – In the SDM, all utypes are prefixed by "Spectrum". – In the SSA, this prefix is dropped on most cases (on purpose!), except for the "Dataset" category, where "Spectrum" is replaced by "Dataset”. Often, a utype or a UCD have a “*” – What does it mean? Does it mean anything? A common typo in UCDs is extra whitespace

6. How to read the “merged table” utype SSA: Query Response SSA: Appendix SDM: Fields SDM: FITS serialization UCD utype notes: When utypes are inconsistent UCD notes: When UCDs are inconsistent FITS

7. Conclusion SSA and SDM are – Plenty of typos Mostly SDM? – Inconsistent within themselves – Inconsistent about the metadata requirements SSA is in general more lax than SDM, on purpose (but the reasoning would imply a more requirements, not less!): “When a generic data model is applied in a specific context, the requirements for what is required, what is optional, and flexibility in what is permitted will vary depending upon how the data model is being used. Hence when data model attributes are indicated as mandatory or recommended in this document, this overrides any similar requirements specified in the Spectrum data model document.”