Standardising units and formats (and ref frames?) in transmission

[Alberto Micol]

> On 15 May 2009, at 21:28, Patrick Dowler wrote:
>
> On Friday 15 May 2009 11:10:19 Alberto Micol wrote:
> > I really hope to hear more (public) voices on this (old) idea of
> > standardising units and formats
> > --if not even reference frames-- for the most common and relevant things
> > that travels onto the wire
> > (not what is presented to the Users).
> ...
> > The approach here proposed (again) is just a transport mechanism, an
> > infrastractural standard,
> > nothing for humans to see, to interpret, or to be affectively 
> attached to.
>
> It seems rather inconsistent to say that astronomers will build their 
> own tools and at the same time these standardised units and formats 
> will not be "seen" by the users.

Obviously users will not see the internal units/formats unless they
become developers. And when they will develop it will be clearer what to 
do if they'll
see standard units/formats.

>
> I agree that users need to be able to write their own task-specific 
> tools - that would be great and a sure sign that the VO works! My 
> feeling is this will happen when someone does enough of the (hard) 
> work and content is uniform enough for users to succeed. I don't think 
> we can mandate that data providers do that work, but we can encourage 
> them, make it easy for them, and maybe in some cases someone else will 
> do it for them (eg. make a service with the same content but with 
> extra computed columns in standard frames/systems/units/whatever... 
> value-added web 2.something goodness).
>
> Or they could all use STIL and Mark will have to do all the hard 
> work.. sounds like plan B :-)
>
> Seriously, I think first we need to make the content available in a 
> more technically uniform fashion (IVOA service standards). Then we can 
> see about more uniform content.
>
Also the technically uniform standard services will benefit by such 
decision.

In some cases only the data providers have the full knowledge to be able 
to perform the
correct translation from their format to anyhting else, while a client 
(even STIL) might
have to take (sometimes wrong) assumptions. Take the Infrared Space 
Observatory time:
it was an on-board very spacecraft specific time. How can a client 
translate that to UTC?
Only the provider can do that. But if the VO does not mandate that, 
chances are
that such things won't be done. If the original ISO time is also needed 
for comparisons,
that can also be transmitted.

Most of all, if the users could start building their own tools then the 
boost to the VO
would be enormous.

Again, I'm only talking of the most common quantities. A limited set, 
should be
easily feasible for all providers. It is "only" matter of agreeing on 
such set.

A nice weekend to everyone,
Alberto