cf2cf

cf2cf
A CF-netCDF to CF-netCDF file converter with aggregation

Description

Convert CF-netCDF files to a single CF-netCDF file.

Variables in the input netCDF files are aggregated into as few multidimensional netCDF variables as possible using the CF aggregation rules based on the CF data model at version 1.5 of the CF conventions.

In particular, differing netCDF variables' units, dimension order and dimension direction are accounted for in the aggregation process.

The conversion is carried out internally using the python cf package, which must be installed.

Man page

cf2cf man page (plain text, html or pdf)

Examples

>> man cf2cf

>> cf2cf −o output.nc file*.nc

>> cf2cf −f NETCDF4_CLASSIC −i −u −v file.nc file[a−z].nc

Installation

cf2cf is bundled with, and depends on, the cf-python package (version 0.9.4 or later). The cf-python package itself also has dependencies.

During installation of cf-python, the cf2cf script is automatically placed in a location in the environment's PATH, but its man page (scripts/man1/cf2cf.1) needs to be moved by hand to a location in the environment's MANPATH.

Issues

I would be very pleased to hear about bugs or suggested improvements. All of the following are currently being investigated:

More than ~1000 input files may cause problems.
Writing large files with many variables in netCDF-3 classic format can be very slow. (NetCDF-4 formats are ok.) This is currently being addressed.
Fields with coordinates containing formula_terms transforms are not aggregatable currently.
Fields with attributes ancillary_variables, flag_values, flag_masks and flag_meanings are not aggregatable currently.

Contact:
E-mail: d.c.hassell@reading.ac.uk

David Hassell
National Centre for Atmospheric Science (NCAS)
Department of Meteorology, University of Reading,
Earley Gate, PO Box 243,
Reading RG6 6BB,
U.K.