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

[Steve Emmerson]

Be careful.  I've seen lots of sea surface temperatures of 38 celsius 
and higher in my work as a research associate at the University of Miami.

Jon Blower wrote:
> Dear all,
> 
> As some of you know, we at Reading have developed an online,
> interactive visualization tool for CF-compliant NetCDF data
> (http://lovejoy.nerc-essc.ac.uk:8080/ncWMS/godiva2.html).  In order to
> create images of the data that are stored in the NetCDF files, the
> tool needs to know a sensible range of possible data values.  For
> example, for sea temperature a sensible range is -5 to 35 C.
> 
> Many data files specify the valid_min and valid_max attributes: these
> define the range of all possible values - outside this range, data are
> interpreted as missing values and are thus "hard" boundaries.  This
> range is often set very wide to ensure that no true data values are
> interpreted as missing.
> 
> I think it would be useful if there were a similar pair of attributes
> (say "suggested_min" and "suggested_max") that are interpreted by
> visualization tools as clues to generating a sensible colour scale,
> but values outside this range are not interpreted as missing.
> 
> Do others think this is sensible, and is there anything similar existing 
> in CF?
> 
> Thanks,
> Jon
>