[CF-metadata] attributes for min/max data values for visualization

[Steve Hankin]

Hi Jon,

Can you really get away with simple attributes to contain the guidance 
on extrema?  For example, if this is 3D data (has a Z axis) and you are 
interested in visualizations at different depths (heights), then the 
"recommended" contour ranges might well need to be different for each 
depth (illustrating why we have tended to back away from this problem 
for such a long time).

Might it make sense to think more in terms of min/max values stored in 
new variables and identified by standard names.  Here is a conceptual 
example for discussion (not a formal proposal, so please cut me slack):

    variables:
      float temperature(time,pres,lat,lon) ;
      float temp_min(pres) ;
        temp_min:parent = "temperature" ;
        temp_min:standard_name = "minimum_over_domain" ;
      float temp_max(pres) ;
        temp_max:parent = "temperature" ;
        temp_max:standard_name = "maximum_over_domain" ;

This approach offers a lot more flexibility.  Does the scope of the 
problem that needs to be solved require this flexibility?

    - Steve

==================================================

Jon Blower wrote:
> Dear Jonathan,
>
> OK, that sounds fine too.  How do we move forward to incorporate this
> into the CF standard?
>
> Thanks, Jon
>
> On 3/28/07, Jonathan Gregory <j.m.gregory at reading.ac.uk> wrote:
>   
>> Dear Jon and Phil
>>
>> I'd suggest actual_min and actual_max, because they would complement the
>> already defined (Unidata standard) valid_min and valid_max.
>>
>> Cheers
>>
>> Jonathan
>>
>>     
>
>
>   

-- 
Steve Hankin, NOAA/PMEL -- Steven.C.Hankin at noaa.gov
7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080, FAX (206) 526-6744

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