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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
The netCDF Operators NCO version 4.4.3 are ready. http://nco.sf.net (Homepage) http://dust.ess.uci.edu/nco (Homepage "mirror") This release is mainly a bugfix and stability release. The new features may interest those using hierarchical group files, those needing Python wrappers for NCO, and those accessing strided data over DAP. Downstream NCO builders will notice many fewer regressions when building NCO on "old" (pre 4.3.1) netCDF libraries. Work on NCO 4.4.4 is underway, still focused on stability and speed. There will be more netCDF4 mop-up, improved group broadcasting algorithms, and, possibly, improved HDF4 support, and new chunking features. Enjoy, Charlie "New stuff" in 4.4.3 summary (full details always in ChangeLog): NEW FEATURES: A. Group broadcasting works with ensembles. Now files containing ensembles (sets of replicated experiments where all ensemble members stored in groups residing under a common group) may be used in binary operations (i.e., ncbo) with "scalar files", i.e., files with the same variables but without ensembles. This is useful, for example, in comparing multiple model results to a single set of observations. ncbo cmip5.nc obs.nc -p ~/nco/data ~/foo.nc http://nco.sf.net/nco.html#grp_brd A. Contributed Python wrappers: Check-out NCOpy by Joe Hamman http://nco.sf.net#python BUG FIXES: A. NCO now employs a much faster access method for hyperslabs. The new method dramatically speeds-up access to strided hyperslabs across DAP connections. Thanks to Rich Signell, Jeff Whittaker, and Anil for help identifying the problem and the solution. B. ncwa and ncpdq could sometimes process (i.e., average, permute or pack) over dimensions besides those specified by the user. This only occurred if the specified dimension name was a proper subset of the name of another dimension. In that case, both would be processed. Reported by Marie-Alice Foujols. C. Fix a problem where cell_methods could be written multiple times in ensemble datasets. D. Segregate regression tests so there are fewer failures on older netCDF libraries. KNOWN ISSUES NOT YET FIXED: This section of ANNOUNCE reports and reminds users of the existence and severity of known, not yet fixed, problems. These problems occur with NCO 4.4.3 built/tested with netCDF 4.3.2-rc1 on top of HDF5 hdf5-1.8.12 with these methods: cd ~/nco;./configure --enable-netcdf4 # Configure mechanism -or- cd ~/nco/bld;make dir;make allinone # Old Makefile mechanism A. NOT YET FIXED (NCO problem)Correctly read arrays of NC_STRING with embedded delimiters in ncatted arguments
Demonstration:ncatted -D 5 -O -a new_string_att,att_var,c,sng,"list","of","str,ings" ~/nco/data/in_4.nc ~/foo.nc
ncks -m -C -v att_var ~/foo.nc 20130724: Verified problem still exists TODO nco1102 Cause: NCO parsing of ncatted arguments is not sophisticated enough to handle arrays of NC_STRINGS with embedded delimiters. B. NOT YET FIXED (netCDF library problem) Probe hidden attributes (chunking, compression) of HDF4 files Demonstration: ncdump -h -s ~/nco/data/hdf.hdf # (dies) ncks -m ~/nco/data/hdf.hdf # (works by avoiding fatal calls) 20131230: Verified problem still exists Cause: some libnetCDF library functions fail on HDF4 file inquiries.Bug report filed: netCDF #HZY-708311 ncdump/netCDF4 segfaults probing HDF4 file
Tracking tickets NCF-272, NCF-273 C. NOT YET FIXED (would require DAP protocol change?) Unable to retrieve contents of variables including period '.' in name Periods are legal characters in netCDF variable names. Metadata are returned successfully, data are not. DAP non-transparency: Works locally, fails through DAP server. Demonstration:ncks -O -C -D 3 -v var_nm.dot -p http://thredds-test.ucar.edu/thredds/dodsC/testdods in.nc # Fails to find variable
20130724: Verified problem still exists. Stopped testing because inclusion of var_nm.dot broke all test scripts.NB: Hard to fix since DAP interprets '.' as structure delimiter in HTTP query string.
Bug report filed: https://www.unidata.ucar.edu/jira/browse/NCF-47 D. NOT YET FIXED (would require DAP protocol change) Correctly read scalar characters over DAP. DAP non-transparency: Works locally, fails through DAP server. Problem, IMHO, is with DAP definition/protocol Demonstration:ncks -O -D 1 -H -C -m --md5_dgs -v md5_a -p http://thredds-test.ucar.edu/thredds/dodsC/testdods in.nc
20120801: Verified problem still exists Bug report not filed Cause: DAP translates scalar characters into 64-element (this dimension is user-configurable, but still...), NUL-terminated strings so MD5 agreement fails "Sticky" reminders: A. Pre-built, up-to-date Debian Sid & Ubuntu packages: http://nco.sf.net#debian B. Pre-built Fedora and CentOS RPMs: http://nco.sf.net#rpm C. Pre-built Windows (native) and Cygwin binaries: http://nco.sf.net#windows D. Pre-built AIX binaries: http://nco.sf.net#aix E. NCO support for netCDF4 features is tracked at http://nco.sf.net/nco.html#nco4NCO supports netCDF4 atomic data types, compression, chunking, and groups.
F. Reminder that NCO works on most HDF4 and HDF5 datasets, e.g., HDF4: AMSR MERRA MODIS ... HDF5: GLAS ICESat Mabel SBUV ... HDF-EOS5: AURA HIRDLS OMI ... -- Charlie Zender, Earth System Sci. & Computer Sci. University of California, Irvine 949-891-2429 )'(
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