Importing aseg-gdf2 files into the GSPy Survey

You can directly import aseg-gdf2 files with a .dat and .dfn file. Pratt, D. A. (2003). ASEG-GDF2 A Standard for Point Located Data Exchange. Australian Society of Exploration Geophysicists, 4(0), 1-34. https://www.aseg.org.au/sites/default/files/pdf/ASEG-GDF2-REV4.pdf

We do not handle importing .des or .met files that seem to be deprecated.

Mapping the DFN to the CF metadata convention

The following is an example of a dfn metadata entry

DEFN 9 ST=RECD,RT=;Latitude:f12.7:UNIT=deg:NULL=-99.9999999,NAME=Latitude

which we map to the CF metadata attributes standard_name, long_name, units, and null_value as follows.

Latitude becomes the standard_name, and is converted to all lower case. UNIT becomes units, NULL becomes null_value. NAME becomes the longer description call long_name

The dfn file also contains a fortran format entry, e.g, f12.7, i5, a16, etc. We maintain that fortran format in the GSPy metadata in case a user wants to export a GSPy dataset to ASEG-GDF2 files.

If entries are not provided for NAME, UNIT, NULL, we simply enter “not_defined” in the GSPy file. It is upto the user then to complete the metadata entry.

When importing aseg_gdf2 files into GSPy, you can provide additional metadata via either json or yml files. See our examples section for more info. The entries in the yml file will overwrite the dfn file entries.