Proposal for SODA test implementations

[Mark Allen]

Dear François,

I would strongly endorse your proposal to have demonstrations of real implementations of the multi-d data standards. 

From the CSP point of view we absolutely need to converge on this first set of multi-d data standards and show that they work.

The minimal requirements were set from the scientific priorities for multi-dimensional data access, and this led to a set of standards that needed to be developed to address those requirements. This has been an important way of ensuring that those standards do what is needed and the requirements were used to keep the scope under control.  This worked well for the SIAv2.0, ObsCore and DataLink standards and even though the process has been long, the emergence of serious implementations of these for data cube access is an important success. 

I would hope that the Access Data now SODA standard, whose role with respect to the minimal requirements is to enable simple cut-outs, would have the same level of management applied to make it converge. Especially after all of the many difficult and hard won compromises and agreements. As new ideas are proposed, I would expect these to be put into a future version and any features outside the minimal requirements should not impact the process.  These standards must really be allowed to be finalised.

regards,
Mark Allen



On 3 Mar 2016, at 16:45, François Bonnarel <francois.bonnarel at astro.unistra.fr> wrote:

> Last of my three emails of today,
> 
>   Let me make a proposal to the DAL community and to data providers willing to expose data  Cubes (dim >= 3) in the VO.
> 
>     The idea is to try to realize the basic scenario described in the CSP requirement by using SIAV2 or OBstap implementations, as well as  DataLink and the current version of SODA spec. This should be operated on real cubes ( 2D images or spectra would not be considered as good validation) and it's not necessary to demonstrate additional (more sophisticated ) server side operations. Additional specifications for Domain metadata or subtilities in pathes to SODA or DataLink use can be added  and should be described but the prototyping should clarify what they really add to the use case realisation. 
>     Demonstrations of implementations or prototypes should occur in DAL session at Cape Town. Contact me if you want to participate and make a demo in Cape Town.
> 
>     The CSP requirements can be found below.
>         I consider that CADC new SODA version is the first of those test implementations for Cape Town 
>          
> 
> Cheers
> François 
> 
> CSP requirements 
> 
> a ) Data Discovery (Query) 
> A service shall return to the client a list of observations, and 
> the corresponding metadata for each observation, meeting the 
> user imposed constraints. In the event that the user places no 
> constraints, the entire list of observations, and the correspondin 
> metadata for each data set, shall be returned. In the event that no 
> data meet the user's constraints, the service shall indicate the 
> absence of any matches. 
> 
> 
> b ) Data Access 
> * Once a user has the list of observations that satisfy the 
> constraints, they select all or a subset of the observations and: 
> * Download the complete science data for each of the 
> selected observations (the service shall return the complete 
>  multidimensional science data and metadata for each selected 
> observation) or; 
> * Download simple cutouts of the science data for each of the 
> selected observations (the service shall be able to extract and 
> return a user specified subset of the complet 
> e multidimensional 
> science data and metadata for each selected observation). 
> 
> 
> Simple Cutout 
> * For a simple cutout, the user specified subset is restricted to 
> be a contiguous interval within each dimension of the multidimensional science data. 
> The user should *not* be allowed to specify subsets with "gaps" or resampling or anything like that. 
> * Spatial: a circle (a coordinate and a radius) 
> * Energy: one interval (from energy1 to energy2) 
> * Time: one interval (from time1 to time2) 
> * Polarization: a list 
> 
> -- 
> =====================================================================
> François   Bonnarel           Observatoire Astronomique de Strasbourg 
> CDS (Centre de données        UMR 7550 CNRS / Université de Strasbourg
> astronomiques de Strasbourg)  11, rue de l'Université
>                               F--67000 Strasbourg (France)
>     
> Tel: +33-(0)3 68 85 24 11     WWW: http://cdsweb.u-strasbg.fr/people/fb.html
> Fax: +33-(0)3 68 85 24 25     E-mail: francois.bonnarel at astro.unistra.fr
> ---------------------------------------------------------------------
> 
> 

Mark Allen
mark.allen at astro.unistra.fr

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