Re: ncdigest V1 #682

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: Re: ncdigest V1 #682
• From: martin.schultz@xxxxxxx
• Date: Tue, 4 Mar 2003 10:21:27 +0100

Topics:
ncrcat
using NCO commands to create climatologies

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Leticia,

     first of all, you should try to understand what a record
dimension is -- this is a synonym for "unlimited" dimension, and it
has a special meaning in netcdf files, because it is the only
dimension in the file, which you can change in size (without having to
create a new file). Typically, the record dimension is used for time
variables. 

     ncrcat will attempt to concatenate files "along" this record
dimension, but for this, it must be present. Please ask the provider
of that file to include a record dimension - since you talk about a
climatology, that sounds like there should be some time information.

     With ncecat it should have worked - but perhaps you specified
your variables with wrong case (netcdf is case-sensitive!). 


Hope this helps,

Martin Schultz

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Cathy,

    I have been through the same, and I would strongly support this
idea. The question is, however, how it can be realized in a generic
way. At a minimum, one will have to agree on a (set of) units for the
time variable (and the name of the time variable), so that an operator
could "understand" the data set. This probably means a change in
philosophy, because until now, the NCOs are completely generic,
i.e. they don't require any knowledge about what is stored in the
files. On the other hand, I would argue that probably 99% of all
netcdf files contain a time variable in one format or the other, so
that "time variable processing" would be very valuable. Another useful
feature would be a conversion between different time units,
e.g. change "days since 1900-01-01" to "days since 1990-06-01
12:00:00" or perhaps even to "days as %Y%m%d.%f".

Regards,

Martin Schultz



-- 
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[
[[ Dr. Martin Schultz   Max-Planck-Institut fuer Meteorologie    [[
[[                      Bundesstr. 55, 20146 Hamburg             [[
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[[ martin.schultz@xxxxxxx                                        [[
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