SED data model v0.92

[Ed Shaya]

Jonathan,
    I am just beginning to look at theSED document.  I do not see where 
one can place an error on each individual point.  Have I missed it?   
This would be needed if there is a complex procedure by which the SED is 
produced (say dozens of  partially overlapping spectra are combined to 
produce a grand SED) and one does not wish to reproduce the procedure to 
get an error bar on a particular point.  In fact, one can easily imagine 
that SEDs will often be exactly this, cause otherwise one may be better 
off with a simpler set of spectra.

Secondly, you have for upper limit information:

"If the data provider has only upper limit information, it should be 
represented by setting the flux value and the lower error value equal to 
the limit. "

But what about the postiiveError limit?  Is it then set to zero?
Also, the lower error value should be called the negativeError value 
since it can be lower or  greater  than the positiveError limit.

Finally, for now, I think redshiftError and redshiftConfidence should be 
children of redshift (in the XML Schema), as all good quantities should.

Ed



Jonathan McDowell wrote:

>A group led by myself and Doug Tody have been working on
>the data model and data formats for the Simple Spectral Access Protocol,
>which represents 1D spectra, time series and spectral energy distributions.
>The document is still at a draft stage but has now reached a level
>of maturity that it may be interesting for people to look at.
>You can find it at
> http://hea-www.harvard.edu/~jcm/vo/docs/spec.html
>and I'll put it on the twiki in the next few days.
>   Jonathan
>
>  
>