Hello Peter,
I was in Cambridge but not ADASS. I had like to participate to your discussion indeed. Anyway, just a few words about what you discussed during ADASS:
Le 30/09/2007 11:39, glemson écrivait :
...
>>> Ugo dicussed 3 levels of access:
>>> 1) low level data, the simulation data itself
>>> 2) certain sections or snapshots from the simulation (e.g. SNAP)
>>> 3) final products, this could be software telescope produced,
>>> catalogs produced from a simulation etc.etc.
>>> #3 is the obvious thing to concentrate on. We doubt 2, but especially
>>> 1, is of interest to observers. Real power and visibility comes from
>>> well selected examples in #3.
I fully agree with you that #3 products (called Level 2 in SNAP, an effect of Fortran vs C array indices certainly ;-) !) are undoubtly most interesting for observers. Amongst these products, mock images (eg projection or slices), data cubes, etc., everything that looks like an image or a spectrum in fact, should be accessible via other SxAP IVOA protocols. That's why, up to now, SNAP did not dealt with this kind of products.
Catalogues produced by a simulation are considered as Level 1 (#2) products since they are generated directly from a raw simulation and shared generally the same structure (3D space objects) as the snapshots (eg catalogues of halos are lists of masses,x,y,z,vx,vy,vz n-uple as particles in a snapshot, but with additional properties). This level of data could be also interesting for an observer. IN fact, any product obtained after some transformation of Level 0 data but keeping the same spatial structure is Level 1 (the definition given in the draft document is however better that this one... but this is just to be short).
Finally, to produce Level 2 (#3) products, a service could have to access at lower level data, as raw data or catalogues. That's also what SNAP is designed for.
So, I think that both Levels 1 and 2 (or #2 and #3) are of interest for an observer.
Best regards,
Herve
-- _______________________________________________________________ Herve WOZNIAK Centre de Recherche Astronomique de Lyon UMR 5574 Université Lyon 1 - CNRS - ENS-Lyon 9, avenue Charles Andre, F-69561 Saint Genis Laval cedex Phone: (+33) (0) 478 868 388 Fax: (+33) (0) 478 868 386 http://www-obs.univ-lyon1.fr/labo/perso/herve.wozniak/Received on 2007-09-30Z14:20:25