I also like "actual_min" and "actual_max": short and to the point.
One point Ill make is that I see a number of well thought out files
using valid_min and valid_max when they really mean actual_min and
actual_max. On first glance this may seem harmless, but it triggers (in
the netcdf-java library default behavior) a costly scan of the data
looking for invalid data, ie values outside that range.
So adding actual_min/max as recommended attributes should help users
from mistakenly using valid min/max. And its very useful for visualizers
to create color scales etc.
Julia Collins wrote:
> On Mon, 9 Jun 2008, Jon Blower wrote:
>
>> I have rediscovered this conversation in the depths of my inbox and
>> thought it might be worth resurrecting. To summarize the discussion
>> so far:
>> 1) I proposed two new standard optional CF attributes (called
>> something like minimum_data_value and maximum_data_value) that would
>> be attached to a variable in a NetCDF file, redundantly holding its
>> actual min and max values in that file. [...] As well as helping with data
>> mining applications, this would act as a hint to visualization
>> packages to provide a first attempt at automatically defining a colour
>> scale range for sensible portrayal. Note that this attribute pair is
>> distinct in purpose from valid_min and valid_max (which contains
>> theoretical extrema, beyond which data is considered invalid).
>>
>
> I support the idea of formalizing these sorts of attributes in some
> way. However, I would prefer a simpler name(s). For example: "actual_min"
> and "actual_max." Less typing :-), and more like the existing "valid_min"
> and "valid_max" attributes.
>
> Julia
> --
> Julia Collins
> National Snow and Ice Data Center
> CIRES, University of Colorado, Boulder
> 449 UCB
> Boulder, CO 80309-0449
> Voice: 303-492-6405
> E-mail: collinsj at nsidc.org
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Received on Mon Jun 09 2008 - 17:53:59 BST
