Dear Jonathan and list,
Just to re-start this debate. The original question was whether there
was (or could be) a pair of CF attributes to identify the min and max
data values in a CF dataset for the purposes of aiding visualization
tools to choose sensible colour scales. Previous posts on this topic
have encompassed suggestions to have "actual" data min and max (for a
particular variable in a file), and also "recommended" min and max
(for visualization hints only) for a particular standard_name (e.g. a
sensible range for sea_water_potential_temperature might be -5 to 40
degC or something like that).
I can see that the "recommended" range might be a contentious issue
and the subject of some debate, so I shall put that aside for the
moment. I still think it would be a very good idea to have a pair of
standard, optional attributes that identify the *actual* min and max
data values in a particular variable in a particular file. This is
redundant information but would be useful for data mining as well as
for visualization.
For an aggregated variable (spanning a number of related netcdf
files), the min and max for the whole dataset would be easy to
calculate, simply by examining the min and max attributes in each
file.
These attributes would be optional, but easy to add to existing
datasets, either through editing the NetCDF files or through other
decorators such as NcML, CDML etc.
I propose calling these attributes value_min and value_max.
What do others think? Is this a sensible addition to CF?
Jon
On 1/10/07, Jonathan Gregory <j.m.gregory at reading.ac.uk> wrote:
> Dear John
>
> > I wonder if we want to promote characterizing whole datasets inside every constituent of the set. Does CF do this in other contexts?
>
> No, because CF does not have a concept of "dataset" yet i.e. there are no
> specific conventions for linking files.
>
> Cheers
>
> Jonathan
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>
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Received on Wed Mar 28 2007 - 07:00:02 BST
