Hi, > If I want to reduce the data volume by representing floating point values > using 'compressed integer'(?), does netCDF have an API for that or would I > have to that myself before writing to the array to the netCDF4/HDF5 file? There is no API for packing floats or doubles in smaller integers in the netCDF C or Fortran libraries, but there is a convention http://www.unidata.ucar.edu/netcdf/docs/netcdf/Attribute-Conventions.html for using the "scale_factor" and "add_offset" attributes to implement packing. A detailed description of how to handle this convention is in the Best Practices document here: http://www.unidata.ucar.edu/netcdf/docs/BestPractices.html#Packed Data Values The netCDF-Java API implements packing and unpacking according to the above convention automatically. Also the NCO (NetCDF Operators) package implements packing according to that convention: http://nco.sourceforge.net/nco.html#Packed-data > Would it be the same for both classic & enhanced models? That simple packing convention will work for both classic and enhanced models, but it's not implemented in the C or Fortran libraries. The netCDF-4 library implements zlib compression as well, for both netCDF-4 and netCDF-4 classic-model formats, and that can sometimes achieve better compression than packing. --Russ > Thanks, > > > ------------------------------------------------------------------------ > Oh-ig Kwoun > > NASA/JPL, California Institute of Technology > 4800 Oak Grove Drive, MS-T264-867 > Pasadena, CA 91109-8099, USA > (Cell) (818) 399-6998 > Tel: (818) 354-3496 > Fax: (818) TBD > ------------------------------------------------------------------------ > Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: UPA-771360 Department: Support netCDF Priority: Normal Status: Closed
NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.