netCDF

NetCDF

• started in 1989
• most used in geoscience community
• array-oriented
• self-describing
  • header, describe:
    • the layout of rest of the file
    • arbitrary file metadata in the form of name/value attributes
• machine-independent
  • endianness being addressed in the libraries

Formats

netCDF classic model


• classic format(default)
  • variables
    • types (char, byte, short, int, float, double)
  • dimensions
  • attributes
• 64-bit offset format
  • support large variables and sizes
• netCDF4/HDF5 format
  • HDF5 data format, with some restrictions

File parts

netCDF file parts


1. The header, containing information about dimensions, attributes, variables, and all attribute values.
2. The fixed-size data, containing data values for variables that don't have an unlimited dimension (if there are any)
3. The record data, containing data values for variables that have an unlimited dimension (if there are any)
   This format has some characteristics important for performance:

• no extra space in the header (by default) or fixed-size data part
• little storage overhead
• a file can grow efficiently only by appending records to the end, growing all record variables together