[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[netCDF #FUM-547235]: NetCDF general questions



We have limited knowledge of IDL, so we may not be able to help much.
If there is some kind of IDL mailing list, I suggest you ask there.
Also, we maintain a page of useful external software that might be of some
help. See http://unidata.ucar.edu/software/netcdf/software.html

Also, the netcdf community has defined a set of conventions
called the CF conventions for specifying information about time, etc.
If there are relevant attributes in your netcdf file, you can check
the conventions to see if a definition is provided.
See http://cfconventions.org/

You write:
> Should it also be defined as "unlimited"?
Unlimited refers to a dimension size so the definition of time
as a dimension will probably be defined as having a size "unlimited".

Determining reasonable chunking sizes is difficult in the abstract.
You might see if these help:
http://www.unidata.ucar.edu/blogs/developer/en/tags/chunking
and
http://unidata.ucar.edu/software/netcdf/docs/netcdf_perf_chunking.html

BTW, thanks for the broken link pointer.


> Hello - We're relatively new to using data in the NetCDF format, as we
> developed and support CDF, but now have a need to work with Heliophysics
> data stored in the NetCDF format.
> A few questions thus far.
> 1) Are there additional NetCDF routines for IDL that support things like
> computing time given a base time and seconds or milliseconds, etc.?
> 2) Is there a standard way to specify time values?  It seems many use a
> base time in seconds and then define in the units attribute a string
> like, "seconds since 2000-01-01 12:00:00"
> 3) All of the data that we'll be dealing with will be time based, so
> thus time will be a dimension and a variable.  Should it also be defined
> as "unlimited"?
> 4) Do you have recommendations for the best way to compute the chunking
> size for use w/ by variable compression?
> 5) Do you have recommendations for computing the chunking size when
> using unlimited dimensioned variables?
> 
> Also, several links from your FAQ page are broken
> http://www.unidata.ucar.edu/software/netcdf/docs/faq.html
> e.g.: http://www.unidata.ucar.edu/software/netcdf/docs/software.html#NCO
> 
> Thanks,
> Tami Kovalick
> 
> --
> Tami Kovalick
> ADNET Systems
> GSFC/SPDF, Code 672
> Greenbelt, MD 20771
> Phone: 301 286-9422
> CDAWeb: http://cdaweb.gsfc.nasa.gov/
> SSCWeb: http://sscweb.gsfc.nasa.gov/
> 
> 

=Dennis Heimbigner
  Unidata


Ticket Details
===================
Ticket ID: FUM-547235
Department: Support netCDF
Priority: High
Status: Open
===================
NOTE: All email exchanges with Unidata User Support are recorded in the Unidata 
inquiry tracking system and then made publicly available through the web.  If 
you do not want to have your interactions made available in this way, you must 
let us know in each email you send to us.