Cube/ImageDM - Comments on Observation-Dataset Overview diagram

[Louys Mireille]

Hi Mark , hi DMers,

Thanks for the update.
Here are my comments about the new diagram binding Dataset and Experiment:

- is there any reason why *ObsDataset *is 'slanted' , i.e is considered 
as an abstract class?

- relationship between Observation->observationID and 
ObsDataset->DataID-> observationID :
the text should clearly state that various situation may appear:
In the CTA project , the DM combines several Observation instances  to 
build up an ObsDataset:
  these two classes may have a N..M relationship in the IVOA Image DM to 
support the various use-cases.

-the *DataModel *Class:
this class was discussed in order to provide a kind of structured label 
for any document expressing the serialisation
of some metadata compliant to an IVOA data model.
I think it should not be hooked to any class , but present as a global 
object in any serialisation of any form
VOTable or XML or FITS .

-*Derived* Class
This is a fuzzy concept that represent the kind of things that can be 
computed from the data,  here SNR, VarAmpl, Redshift.
I understand we need it but cannot precisely these kinds of 
interpretation results.
*Derived *could be just a container with a variation of computed 
measures, SNR, VarAmpl, Redshift , etc...
then this can be re considered after some practical usage.

- composition of *Observation *with *BaseTarget*
I suggest to have two links of composition on AstroTarget and Target , 
with cardinality 0..1.

- *position *in a *Target*: an AstroCoordinate from STC DM  would be 
directly usable from an application.
an intermediate type does not seem useful to me here.

best wishes.
Mireille




  Le 10/05/2014 20:23, CresitelloDittmar, Mark a écrit :
> All,
>
> Another round of updates, nothing very significant.   Most stem from 
> feedback and/or STC review.
>
>   + ivoaTypes: added 'quantity' package to better reflect the vo-dml 
> native model.
>   + Dataset/Experiment:  I combined the diagrams into one, more 
> complete picture.
>   + Dataset Types:  added SED to DataProductType enumeration.  (held 
> off on LightCurve until we get the source reference.. or just decide 
> it should be added).
>   + STCMod: ErrorModel - added QualityCode from Spectral document.. 
> hanging off <Uncertainty> and used in Coordinates.
>   + STCMod:Coordinates - changed type of quality -> QualityCode; 
> sysError -> UncSymmetrical1D/UncRadius2D
>         since systematic errors are always symmetrical
>   + STCMod:RefFrame - made stdSpaceRefFrame abstract; show reference 
> to Frame from CoordRefFrame for clarity.
>   + STCMod:Types - update diagram with ivoaTypes change. corrected 
> ownership of CSize tree (s/b STC)
>
> Mark
>

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