WD-SIA-2.0, going forward

[Patrick Dowler]

This sounds exactly like the scope of AccessData, where the caller 
decides on the operations they want performed. So I will ask the 
question again in a different way:

Is the purpose of this "mode" parameter at the query stage to cause the 
result to only include records where a specific access data operation is 
available? And to pre-compute and include the access data URL directly 
in the query result?

If so, this is an optimisation of the general case that comes at the 
cost of coupling this mode parameter in the query capability to the 
operations available in the access data capability.

Pat

On 07/01/14 12:18, Douglas Tody wrote:
> The main thing missing at this point is a "mode" parameter of some sort,
> to give the client control over automated virtual data generation.  Also
> possibly some clarity on the use of POS to define the ROI for image
> generation, and a description of the AVDG capability at the registry /
> VOSI level so that a client can determine if a service has this
> capability.
 >
> For mode, what I had before was "archival" (whole images), "cutout" (do
> not interpolate or otherwise recompute pixels), and "match" (do
> everthing the service can do to match the ideal image, e.g.,
> reprojection, mosaicing, etc.).
>
> We don't want to just always do AVDG as it is expensive and will slow
> down the query, so a mode parameter or some such is needed to enable the
> feature.  Whether or not new pixels are computed is critical or
> irrelevant depending upon the client application, so control is needed.
>
> Other than that we appear to have the critical elements, since virtual
> images can be described in the query response and the provided acref can
> point to AccessData to generate the image.  DataID.CreationType, which
> we already have in the data model, can tell whether the described image
> is archival, a cutout, etc.
>
> Most of this logic applies to Spectra and TimeSeries as well, and
> would want to be included in a future version of these services.

-- 

Patrick Dowler
Canadian Astronomy Data Centre
National Research Council Canada
5071 West Saanich Road
Victoria, BC V9E 2M7

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