Version 5.1.0 of the netCDF Operators (NCO) has been released. NCO is an Open Source package that consists of a dozen standalone, command-line programs that take netCDF files as input, then operate (e.g., derive new data, average, print, hyperslab, manipulate metadata) and output the results to screen or files in text, binary, or netCDF formats.
The NCO project is coordinated by Professor Charlie Zender of the Department of Earth System Science, University of California, Irvine. More information about the project, along with binary and source downloads, are available on the SourceForge project page.
From the release message:
Version 5.1.0 supports the new netCDF 4.9.0 features for filters and
quantization. This is a significant new feature that justifies the
version bump from 5.0.7 to 5.1.0. There is also an ncremap fix for
sub-sub-gridscale regridding, e.g., landunit-specific regridding.
Users of sub-SGS regridding, and anyone interested is using modern
compression or quantization algorithms such as Bzip2, Zstandard,
Granular BitGroom, and BitRound.
New Features
-
All numeric NCO operators support new compression features
when linked to a default installation of the latest netCDF, 4.9.0.
These features and how to access and tune them are extensively
documented in the manual. Suffice it to say that all NCO users
now have transparent access to modern lossless (Bzip2, Zstandard)
and lossy (BitRound, Granular BitRound) compression algorithms.
Codecs from the netCDF C-library, the Community Codec Repository
(CCR), and from user-installed HDF5 filters may all be used.
The commands will look something like this:
ncks --cmp='granularbr,3|shuffle|zstandard,3' ... # Long-names ncks --cmp='gbr,3|shf|zst,3' ... # Abbreviations and levels ncks --cmp='gbr|shf|zst' ... # Default levels ncks --cmp='f32|gbr|shf|bz2|dfl|zst' ... # Multiple codecs ncwa --cmp='gbr|shf|zst' ... # Other operators... ncbo --cmp='gbr|shf|zst' ... # All numeric operators, in fact ncclimo --cmp='btr\|shf\|zstd' ... # Climo generator ncremap --cmp='btr\|shf\|zstd' ... # Regridder
Full documentation (including figures) is at http://nco.sf.net/nco.html#compression
Thanks to Ed Hartnett (NOAA) and Dennis Heimbigner (Unidata) for guiding the addition of these features into the CCR and netCDF.
Additional details are available in the ChangeLog.
