> So adding actual_min/max as recommended attributes should help users > from mistakenly using valid min/max.
Yes, I agree. I've seen this problem lots of times too. I think in general it's quite hard to decide what to put in valid_min and valid_max so people just (incorrectly) use the actual min/max. Jon On Tue, Jun 10, 2008 at 12:53 AM, John Caron <[EMAIL PROTECTED]> wrote: > 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: [EMAIL PROTECTED] >> _______________________________________________ >> CF-metadata mailing list >> [email protected] >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > -- -------------------------------------------------------------- Dr Jon Blower Tel: +44 118 378 5213 (direct line) Technical Director Tel: +44 118 378 8741 (ESSC) Reading e-Science Centre Fax: +44 118 378 6413 ESSC Email: [EMAIL PROTECTED] University of Reading 3 Earley Gate Reading RG6 6AL, UK -------------------------------------------------------------- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
