Why does the CF/ACDD compliance checker complain on my Conventions statement?

By steingod | Fri, 09/11/2020 - 14:28

The NorDataNet compliance checker tells me that I don’t have a Conventions attribute present that clarifies that it follows ACDD-1.3 standard, but I have a Conventions attribute containing "ACDD-1.3, CF-1.8"?

The reason for this issue is that the Conventions attribute is an attribute of both ACDD and CF.  It can be a bit confusing as:

  • acdd wants comma separated
  • cf wants either space (preferred) or comma separated

According to CF:

"It is possible for a netCDF file to adhere to more than one set of conventions, even when there is no inheritance relationship among the
conventions. In this case, the value of the Conventions attribute may be a single text string containing a list of the convention names separated by blank space (recommended) or commas (if a convention name contains blanks). This is the Unidata recommended syntax from NetCDF Users Guide, Appendix A. If the string contains any commas, it is assumed to be a comma-separated list."

Thus, you should format youyr Conventions attribute with comma as the separator.