Symptom:
When Importing an ASEG-GDF using Database > Import > ASEG-GDF I get the following error:
The ***.dfn ASEG-GDF header file has an invalid NULL= Value section at line ###.
Resolution:
The error indicates that the input on line ### of the .dfn file is not what is expected for the "NULL =NULL".
For example: "DEFN 4 ST=RECD,RT=; locmethod: A89: NULL=NULL, NAME=Location Method".
There are two options to work around the problem:
1) Open the DNF file in a text editor and chang all "NULL=NULL" to "NULL=-999".
For example: "DEFN 4 ST=RECD,RT=; locmethod: A89: NULL=-999, NAME=Location Method"
Or
2) Remove the option all together
For example: "DEFN 4 ST=RECD,RT=;locmethod:A89,NAME=Location Method"
Once the edit to the file is completed, the import executes successfully.
Root Cause:
The import is expecting an integer not a string as a variable input for NULL. It appears that the ""NULL=" expression is not even needed for channel of "string" type.
Notes:
This issue has started as after an apparent change to the data formats on the Australian GADDS (Geophysical Archive Data Delivery System) data portal.