[Data Characterisation]: Spatial domain models comparison

[Andreas Wicenec]

Dear all,

I have a couple of immediate comments:

0.) The suggested column does not always give enough detail on how it would be 
done, e.g. Pat's way, Doug's way or yet another one?

1.) How will the astrometric accuracy of the spatial coverage be represented 
in a single floating point value? A real WCS contains many different 
parameters which all have their own error associated and they can be quite 
different. Moreover the parameters for the spatial coverage have different 
units (fill_factor and shape are dimensionless, fov is probably in degrees.

2.) What is a spatial sensitivity?? In my view the only way to represent 
something like this is a sensitivity map as Alberto mentioned. The parameters 
given in the table are certainly not representing anything like spatial 
sensitivity, but global flux sensitivities deducted (how?) from the overall 
FOV. The *how* is actually important here because if this is done differently 
the values are not comparable. Note that I'm not against these parameters in 
general I'm just saying that the name 'spatial sensitivity' should be 
changed.

3.) The concept name 'Photometric Accuracy' (first column) should also be 
changed to flux uncertainity to be more consistent with the other concept 
names in the same table.

Cheers,
Andreas

On Thursday 06 November 2003 22:25, Alberto Micol wrote:
> Dear All,
>
> I have tried to compare the spatial part (to start with) of the various
> coverage models I have seen so far.
>
>
> Notes:
>
>    1. Polarisation not included.
>    2. Probably too biased towards the optical regime; please, X, Radio,
>       Interferometry experts: intervene!
>    3. Bob, Pat, Doug: My apologies if I have missed something, please
>       send me any necessary corrections.
>    4. Suggested names are likely to change after similar work on other
>       axes is carried out (aim: uniform description of different axes).
>    5. I still have to read Arnold's STC Metadata document! It should
>       really be included in the comparison here. But since reading it
>       could take me a while, may I ask you
>       Arnold to help me filling the gap ? sorry ...
>
>
> Alberto
>
> http://archive.eso.org/~amicol/VO/DM/coverage/spatial_comparison.html
> <http://archive.eso.org/%7Eamicol/VO/DM/coverage/spatial_comparison.html>