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

[Anita M. S. Richards]

On Mon, 18 May 2009, Alberto Micol wrote:

> On 18 May 2009, at 11:58, Anita M. S. Richards wrote:
>
>> For example, I publish data in Galactic coordinates. If someone wants to 
>> search in RA and Dec then a rough conversion is quite quick, as long as 
>> they don;t mind getting back a region which may be slightly larger than 
>> they asked for. But, we have had repeated complaints from users in the past 
>> who want to search Galactic plane surveys in Galactic coordinates, since a 
>> simple box (from an image or catalogue) will give them what they want, but 
>> in RA and Dec it is horrid.
> As Francois puts it, a galactic search box is nothing else than
> a equatorial box plus an angle. Not that horrid.

It is not practical for images! And it is very non-linear for large 
regions, taking sky curvature into account.

>> Or, I want data with a certain spectral resolution which I specify in 
>> wavelength unts, but the data are in frequency units with a non-linear 
>> conversion - i.e., the spectal resolution at one end of the bandpass is 
>> different from that at the other, if the units are changed.
> I'm asking for unification of units and formats: wavelengths always in 
> meters, frequencies always in Hz. I was not pushing to have frequencies 
> always in keV.  No complex conversions, no re-gridding, nothing subject
> to interpretation, nothing that can corrupt the original piece of 
> information.

Ah, that is better - sorry I missed that!

But why is it so difficult for us to apply SI prefixes, either?

Thanks very much Alberto,

a