netCDF version 4 has many features not found in earlier versions of the library and is implemented on top of HDF5. This module can read and write files in both the new netCDF 4 and the old netCDF 3 format, and can create files that are readable by HDF5 clients. The API modelled after Scientific.IO.NetCDF, and should be familiar to users of that module. Many new features of netCDF 4 are implemented, such as multiple unlimited dimensions, groups and zlib data compression. All the new primitive data types (such as 64 bit and unsigned integer types) are implemented, except variable-length strings (NC_STRING). User defined data types (compound, vlen, enum etc.) are not supported. WWW: http://code.google.com/p/netcdf4-python/