[QUANTITY] Requirements and apology

[Alberto Micol]

>
>
>Dave -
>
>If we are talking about data values, WCS, data quality, etc., then we
>are modeling an entire dataset, not a quantity.  We need to address both
>issues but they are at opposite ends of the spectrum.  Quantity needs
>to be a low level concept (about the same level as a UCD) or it is being
>confused with something else.
>
>	- Doug
>
David,

I was also confused ... It's easy to get confused when words are too 
generic.
Quality means many different  things, eg:

Quality Flag: a flag image to indicate bad pixels and the like
              aka Data Quality

Image Quality: the seeing for an optical image from the ground

Quality of calibration: the accuracy of the astro-spectro-photometric 
calibration


So it is probably better not to call it Quality,
and use instead Quality_Flag (isn't that what you had in mind ?)

>QUALITY - gives a set of flags and/or enumerated values for each value in
>the DATA component.
>
>  
>

But, as Doug suggests, in that case we are not speaking of Quantity
anymore.

Alberto

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