Re: RNetCDF -- R Interface to NetCDF Datasets

• To: "Pavel Michna" <michna@xxxxxxxxxxxxx>
• Subject: Re: RNetCDF -- R Interface to NetCDF Datasets
• From: "David Pierce" <dpierce@xxxxxxxx>
• Date: Mon, 2 Aug 2004 09:29:46 -0700 (PDT)

In the interests of avoiding possible confusion, I'd like to point out
that there are already existing R packages on CRAN that implement these
functions. The package "ncdf" interfaces to the netCDF library, and
"udunits" interfaces to the udunits library. (Disclaimer: I'm the author
of both those packages.) These packages have been available for a year or
so, and I update them when I get bug reports. I presume the new RNetCDF
package is not compatible with either of the existing packages, so I
suggest people not try to mix calls to them.

Regards,

--Dave

---------------------------------------------------------------
David W. Pierce        / Climate Research Division
Scripps Inst. Oceanog. / (858) 534-8276 (voice)
dpierce@xxxxxxxx       / (858) 534-8561 (fax)
---------------------------------------------------------------

Pavel Michna said:
> Dear all,
>
> I just released version 1.0 of the RNetCDF R package on CRAN
> (Comprehensive R Archive Network, http://cran.at.r-project.org/)
> under the terms of the GNU General Public License (GPL).
>
> This package provides an interface to Unidata's NetCDF library functions
> (version 3) and furthermore access to Unidata's udunits calendar
> conversions. The routines and the documentation follow the NetCDF and
> udunits C interface, so the corresponding manuals can be consulted for
> more detailed information.
>
> The main aims of this package are:
> - to provide full read/write access to all NetCDF datasets (supporting
>   all external NetCDF data types)
> - to provide a low level interface which allows the user to write his
>   own (customized) NetCDF read/write functions in a simple way
>
> This package requires Unidata's NetCDF and the undunits library already
> installed on the system.
>
>
> Feedback is greatly appreciated.
>
> Pavel
>
>
> I would like to thank Juerg Schmidli for his excellent comments and
> suggestions during the development process of this package and This
> Rutishauser for testing the package from the user's perspective.
>
>
> ------------------------------------------------------------------------
>
> Pavel Michna (PhD Student)                  Tel:     +41 (0)31 631 85 42
> Climatology and Meteorology (KLIMET)        Fax:     +41 (0)31 631 85 11
> Institute of Geography                      E-Mail: michna@xxxxxxxxxxxxx
> University of Bern
> Hallerstrasse 12
> CH-3012 Bern/Switzerland
>
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------
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>
>



>From owner-netcdfgroup@xxxxxxxxxxxxxxxx Tue 3  2004 Aug 00:51:01
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Date: Tue,  3 Aug 2004 00:51:01 +0200
From: Pavel Michna <michna@xxxxxxxxxxxxx>
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To: dpierce@xxxxxxxx
Subject: Re: RNetCDF -- R Interface to NetCDF Datasets
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Reply-To: Pavel Michna <michna@xxxxxxxxxxxxx>

Quoting David Pierce <dpierce@xxxxxxxx>:

> In the interests of avoiding possible confusion, I'd like to point out
> that there are already existing R packages on CRAN that implement these
> functions. The package "ncdf" interfaces to the netCDF library, and
> "udunits" interfaces to the udunits library. (Disclaimer: I'm the author
> of both those packages.) These packages have been available for a year or
> so, and I update them when I get bug reports. I presume the new RNetCDF
> package is not compatible with either of the existing packages, so I
> suggest people not try to mix calls to them.

That's correct. I'm sorry that I forgot to mention this. However both packages 
(ncdf and netCDF) are acknowledged in the manual. 

Of course the new package is not compatible with the existing two -- otherwise 
it wouldn't make sense to create a new one.

To avoid more confusion, I just want to point out the important differences:
- The "RNetCDF" package starts strightforward from the NetCDF C interface,
  whereas the "ncdf" package goes a more object-oriented way.
- All external data types are covered for variables and attributes in the
  "RNetCDF" package, whereas the "ncdf" package does at least not support
  attributes of type NC_BYTE for read/write. To my knowledge, the "netCDF"
  package does not support NC_BYTE at all.
- The new package contains functions for renaming, copying and deleting
  attributes and for renaming dimensions and variables, which is not covered
  by the two other packages.
- Regarding the "udunits" package: I just implemented the calendar conversions
  because that is often needed. All other udunits functionality is covered
  exclusively by the "udunits" package.


Regards,
Pavel

------------------------------------------------------------------------

Pavel Michna (PhD Student)                  Tel:     +41 (0)31 631 85 42
Climatology and Meteorology (KLIMET)        Fax:     +41 (0)31 631 85 11
Institute of Geography                      E-Mail: michna@xxxxxxxxxxxxx
University of Bern
Hallerstrasse 12
CH-3012 Bern/Switzerland

------------------------------------------------------------------------



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• References:
  • RNetCDF -- R Interface to NetCDF Datasets
    • From: Pavel Michna