Re: [Plastic-devs] spectrum load message

[Isa B. <Isa...@sc...>]

Dear Mark,

I agree with the approach about defining additional arguments in the 
message related more to the type of object (spectrum) than to the 
format  of this object (votable, fits..). In fact, this is what we tried 
to do when we defined the first SSAP definition.
During the process of implementation of VOSpec, we found that only a few 
parameters are needed to manipulate most of the spectra formats. Of 
course, not all the possible spectra serializations can be used in 
VOSpec, but that collection of parameters allows our application to 
display thousand of spectra in different formats from ~15 different 
projects.

List of parameters:  C: compulsory - O: Optional
------------------------------------------------------------------------------------------------------------------------------------------- 

Title - <title> - C - e.g. "ISO SWS01  Spectrum Target: M31_BULGE"
URL - <url> - C - e.g.   
"http://pma.i....../jsp/product.jsp?obsno=40001501"
ServerTitle - <server_title> - O - e.g. "ISO Data Archive"
WaveLengthColumnName - <wave_column_name> - C - e.g. SWAAWAVE
FluxColumnName - <flux_column_name> - C - e.g. SWAAFLUX
WaveUnitsScaleq  - <wave_units_scaleq>  - C - e.g. 1.E-6
WaveUnitsDimeq  - <wave_units_dimeq>  - C - e.g.  L
FluxUnitsScaleq    - <flux_units_scaleq>    - C - e.g. 1.E-23
FluxUnitsDimeq    - <flux_units_dimeq>    - C - e.g. MT-2
Ra   - <ra> - O - e.g 10.691809995
Dec - <dec> - O - e.g    41.27003
Format - <format> - C - e.g spectrum/fits 
--------------------------------------------------------------------------------------------------------------------------------------------- 


Our proposal is to have (at least) all the compulsory fields in the 
message, so VOSpec (as message consumer) and e.g. Aladin and Astroscope 
(as message senders) could be immediately updated to load spectra using it.
Note that all the information requested is already present in the 
existing SSAP services, and it is going to be included (perhaps with 
some minimal syntax changes) in the next SSAP specification.

I would like to have your opinion about this and hopefully discuss it in 
Moscow, if some of you are coming.

Cheers,
Isa



Mark Taylor wrote:

>Plastic Pals,
>
>I have documented a new proposed message for loading spectra at
>
>   http://eurovotech.org/twiki/bin/view/VOTech/PlasticMessagesProposal
>
>I had discussions with various people at Strasbourg about this;
>it is unlike the votable/loadFromURL and fits/image/loadFromURL
>messages in that it relates to the semantic content (it's a spectrum)
>rather than the data format (it's a FITS file) of the resource
>at the URL.  The reason for this is that there is a very wide range
>of possible serializations of a spectrum/SED (FITS 1-d array, FITS
>binary or ascii table, VOTable, FITS or VOTable serialisations of
>DM spectral data model as described at
>http://www.ivoa.net/internal/IVOA/IvoaDataModel/spec98c.pdf, ...),
>trying to cope with all possibilities could lead to an explosion
>in the number of messages.
>
>There are arguments for and against doing it this way, but on pragmatic
>grounds I think this is the most workable solution.  If you disagree,
>feel free to continue the debate here.
>
>Mark
>
>  
>