NCAS Data Standards

If given a file to check where the file name starts with ncas-, as in the start of an NCAS instrument name, and no template or specs are specified, then checksit will attempt to find specs to check the file against depending on which NCAS Data Standard is being used.

NCAS-GENERAL

Automatic use of spec files

If the file is a netCDF file with the Conventions global attribute containing one of NCAS-GENERAL, NCAS-AMOF or NCAS-AMF it its value, the file is identified as needing to conform to the NCAS-GENERAL data standard. checksit then identifies which version of the standard is being used, using the numbers that follow the standard identifier in the Conventions attribute. The data product and deployment mode are obtained from the file, and specs for product and deployment are added to specs for global attributes and file naming for that version of the standard.

Downloading of new versions

If specs for the version of the standard do not exist within specs/groups, checksit will attempt to download the vocabs for that version and create the spec files using the make_amof_specs function within checksit/make_specs.py. However, if checksit cannot find the vocabs for that version, or does not have permission to write into the specs/groups folder, then an error is raised.

NCAS-Radar

Similarly to the NCAS-GENERAL standard above, if NCAS-Radar is in the Conventions global attribute of a netCDF file, then checksit will use specs defined for the identifed version of the NCAS-Radar data standard.

NCAS-IMAGE

If instead of a netCDF file checksit is checking an image file, based on the file extension being one of png, jpg or jpeg (or uppercase versions), and the file has the XMP-photoshop:Instructions metadata tag with a value mentioning the NCAS Image Standard, then checksit will find specs related to NCAS-IMAGE. The version of the standard is identified using the Instructions tag, and specs relating to either the photo or plot data product are selected depending on the file name. The data product spec is combined with a global tags spec file that covers tags required by the standard regardless of which data product is used.