Version: 9.12.0
Notes on the MED file format


The MED file format is a specialization of the HDF5 standard, and existed well before MEDCoupling. Take a look at the HDF5 Group website for more details on HDF5 itself. It focuses on (potentially) big amount of data, and the design philosophy was to facilitate a parallel usage.

The official documentation of the MED-file format is available on-line (in French) in your SALOME installation at:


Remember that the term "MED-file" denotes both:

  • a file format on disk (I/O)
  • a comprehensive low level C library to read/write MED files (now with a Python wrapping) and authored by Eric FAYOLLE (EdF R&D).

What does it look like?

The picture below shows an UML-like diagram of the MED file format. We see for example that the mesh name is the unique key linking a field to its supporting mesh.

Functional diagram of the MED file format