Re: [thredds] GRIB variable name changes in 4.3

I have suggested a GRIB table registry in the past, not that I have gotten
much enthusiasm in response.

I still think the registry is essential, however, enthusiasm or not.

While you are correct that your name conversion is problematic, as users of
GRIB files we need to really solve the problem of what is in a particular
GRIB variable.  You could easily, for example, produce the wrong long_name
if you don't really know what is in the variable, which will mislead the
users.  And ultimately the user needs to know what is there, particularly
if it is hard to find out.

I know how hard it is to get GRIB variables right.  So I understand why you
want to change.  I just wonder if we can address the underlying problem.

Benno





On Mon, Feb 27, 2012 at 7:02 PM, John Caron <caron@xxxxxxxxxxxxxxxx> wrote:

> Hi Cathy:
>
>
> On 2/27/2012 4:36 PM, Cathy Smith wrote:
>
>> John
>> I believe users read from netCDF vs grib files both because reading from
>> grib is not easy and because netCDF provides
>> metadata that is human readable. Changing variable names to
>> VAR__.... is not human readable. Users doing a ncdump would be
>> forced to read through non-standard metadata attributes to see what the
>> variable
>> was (or refer to grib tables which would be different
>> for grib1 vs grib2).
>>
>
> A human readable name will be in the standard attribute "long_name" for
> each variable. Also, the NCEP "short name" is now also in the variable
> attributes when its available.
>
>
>  These grib tables wouldn't necessarily be handy to
>> most users. Users who have scripts now to get data
>> would have to change their scripts in a way that isn't straightforward
>> and also (to me) seems more subject to typos and similar errors.
>>
>
> Yes, scripts will have to be changed (once).
>
>
>
>> While I see that for some developers, the change might make things
>> easier, it would not be for all developers and it certainly would not
>> for most scientists and researchers using TDS files directly. They don't
>> have the time or patience to have to look these things up when they just
>> want to know about the contents of a file quickly, which IS possible now
>> via TDS.
>>
>
> Really, this isnt about who is convenienced. Its about very deep design
> differences between GRIB and netCDF that make this a hard, perhaps
> impossible, thing to do well. The current scheme doesnt work, and about 20%
> of NCEP/IDD names are simply wrong, and an unknown percentage of non-NCEP
> names are wrong. So some things must break. Following the advice to never
> waste a really bad crisis, the thinking is to break them all, but only once.
>
> John
>
>
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-- 
Dr. M. Benno Blumenthal          benno@xxxxxxxxxxxxxxxx
International Research Institute for climate and society
The Earth Institute at Columbia University
Lamont Campus, Palisades NY 10964-8000   (845) 680-4450