Hi John,
On Tue, 24 Apr 2001, John Caron wrote:
> Davies, Harvey wrote:
> > Firstly, I am having second thoughts about my suggested terms 'external' and
> > 'internal'. A respected
> > colleague thought they meant the opposite of what I meant. So how about
> > just 'disk value' and 'memory value?
> > Or 'physical value' and 'logical value'?
>
> Ive been using "external (packed)" and "internal (unpacked)". Does that
> disambiguate it for your colleague?
This seems reasonable. The User's Guide (UG) is consistent in using
"external" to refer to data in a netCDF file.
> > There are two cases.
> > _FillValue is a valid value if it is within a valid range defined by
> > valid_range, valid_min, valid_max.
> > If none of these three attributes are defined then it is assumed that
> > _FillValue is a missing value &
> > should be used to define one end of the valid range.
> >
> > So if you want to use _FillValue to initialize a variable to a valid value
> > 0, then you must define at
> > least one of valid_range, valid_min, valid_max.
>
> this seems reasonable to me. Does anyone have datasets where this
> algorithm would be wrong?
A dataset that was written with a _FillValue within a specified valid range
would not have that _FillValue treated as the valid default data value by
many existing applications, i.e., such a dataset would break most existing
applications. It's confusing to have _FillValue take on opposite meanings
depending on whether or not a valid range is defined. I'd prefer that your
interface didn't support this interpretation, especially since the UG
recommends against it.
Brian
-----------------------------------------------------------------
Brian Eaton | email: eaton@xxxxxxxx
Climate Modeling Section |
National Center for Atmospheric Research |
P.O. Box 3000, Boulder, CO 80307 |
