Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
NetCDF is a great, portable data format but the resulting files are _not_ small. This has lead many groups to try different ways to reduce the file size that complicates netCDFs simple data access methods (scale and offsets, data masks). Others just gzip up the data files and uncompress them when necessary. This usually yeilds a 70-90% reduction in file size but makes makes access cumbersome, especially if you are reading large files off cdroms. It would be nice to access these compressed files directly. I have written a set of modifications to the netCDF library source that allow exactly that. This makes a drop in replacement that will allow transparent access to both compressed and uncompressed netCDF files. You just have to relink against the znetcdf library. Creating compressed netCDF files requires a small change to the flags in the nccreate routine. There is a page with a more complete explanation, the source changes, instructions on how to patch the netcdf-3.3.1 source, and some perfomance numbers: http://snow.cit.cornell.edu/noon/z_netcdf.html This has been used on the following platforms with not problems: dUNIX, MacOS, linux, IRIX, Solaris, AIX, openstep, Rhapsody. If folks want, and contribute, I will collect precompiled libraries on this link as well. Try it out and send me your comments. --Bill Noon Northeast Regional Climate Center Cornell University
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